# Motor Torque Speed Curve

The torque increases as we are applying more power and the speed is decreasing. Mechanical time constant: The time it takes the unloaded motor to reach 63% of its no load speed under a constant voltage, starting from rest. The site does a nice job in explaining torque/speed curves, and how the graph of torque vs angular speed is essentially linear for DC motors. A Nidec Group Company. Motors have changed. Performance curve. At an elevated motor temperature, the slope of the DC motor curve increases as a result of an increase in no-load speed and a decrease in locked rotor torque (sometimes referred to as stall torque). Torque - speed curves are generated by plotting motor speed, armature current, mechanical output power, and efficiency as functions of the motor torque. Its value remains almost the same or ‘flat’ across most of the engine speed range (2500-4000 rpm). torque speed curve of crusher cone crusher versus motor speed. Rated torque and rated speed are useful terms regarding the application’s torque and torque curve. An ECU is programmed to meet the torque needs stated by the manufacturer, with many engines set up to form as flat a torque curve as possible for even distribution across the rev range. Hence, in the normal working region of the motor, the value of the slip is small. ; The starting torque in the split phase motor is directly proportional. 1 Motor speed-torque curve Refer to Figure 2. The maximum torque required by the motor is typically the sum of torque during acceleration, torque due to the load, and torque to overcome friction. Motor Calculations • Calculating Mechanical Power Requirements • Torque - Speed Curves • Numerical Calculation • Sample Calculation • Thermal Calculations Calculating Mechanical Power Requirements Physically, power is defined as the rate of doing work. Diesels seem so quick because they have relatively flat torque curves. On the integral-horsepower curves, consider how the AC induction-motor curve past 60 Hz falls off asymptotically to the X axis: Although it outputs constant torque to 60 Hz (and typically outputs. 5 (7 ratings) Course Ratings are calculated from individual students’ ratings and a variety of other signals, like age of rating and reliability, to ensure that they reflect course quality fairly and accurately. Black Bruin, LSHT Motors are the perfect fit for any wheel or drum application. The only part of the curve, which is almost linear, is good for operation. The rotation region that provides maximum or high torque varies depending on the electric resistance, so changing the cage materials or geometry makes it possible to study the motor characteristics that most closely meet the goals of the design. This is the dynamometer GUI created by the Motor Torque Test Bench Team at UTD. For example in the curves below the speed torque curve for the CVK245AKCVK245BK stepper driver indicates that 24VDC is applied to the motor windings while the curve for the RKS545 stepper driver was created with 162VDC being applied to the windings. We later found through our lab experiments that K1 = 1432. This type of switching is obtained using a mechanical spring-loaded centrifugal switch. For every motor, there is a specific Torque/Speed curve and Power curve. Axis Name Here; Motor Parameters; Speed vs Torque. Figure 3 shows a Thevenin's equivalent of the stator. Rated torque and rated speed are useful terms regarding the application’s torque and torque curve. Also shown is a desired speed+torque operating point for the motor+gearbox combination, showing that only the G = 4 gearbox meets our specification. g)What are the advantages of single phase,25KV,50 hz transmission line for locomotive train. As you can see from the graph speed and current are linear functions of torque so you might need only two measurements to draw these graphs. Title: msd 101 Subject: Motors and Actuators Created Date:. ©2019 Nidec Motor Corporation. The torque/speed curves shown below are actual curves for the green maxon motor (pictured at right) used by students in 2. Limited starting torque even below electric motor nominal torque. 6 6 9 15 18 30 36 60 90 120 180 200 The normal torque is that the motor and gearhead are directly coupled. (The engine was held to 5,400-RPM with the MIRAGE and to 4,700-RPM with the REVOLUTION4. Solid torque curves represent thrust, and dashed torque curves represent output power. As a general rule, the application determines the drive. It can be seen that drop in speed with increased load is much more prominent in series motor. It is found from above that when speed is high, torque is low and vice-versa. All motors have a "torque vs speed" characteristic. Torque Equation of DC Motor. 14 shows how the motor torque-speed curve would change if rotor resistance is increased and all other parameters in the motor equivalent circuit stay the same. NEMA 17 Rotary Stepper Motor Drawing. Motor speed-torque curve Pull-out, breakdown or maximum torque, obtainable over the entire speed range. N/Ta Characteristic (Mechanical) N/Ta Characteristic. The advantage of this type of inferred torque calculation is that no electrical or mechanical measurements, which may be quite costly, are needed. Torque Speed Curve For Johnson KC 613L Motors. The motors’ have achieved the IP69 water protection rating and encapsulated winding enable the motors to last much longer than general purpose products in tough washdown conditions. That said, when operating a self-cooled motor at reduced speeds, temperature rise must be factored in. 8 Torque-speed characteristics for a single phase full converter drive. Drives however, typically limit the maximum available torque to 70% of Tmax. The single-step response character- istics of a stepper motor is shown in figure 11. On the integral-horsepower curves, consider how the AC induction-motor curve past 60 Hz falls off asymptotically to the X axis: Although it outputs constant torque to 60 Hz (and typically outputs. The motor’s back electromagnetic field (EMF) can be measured to acquire its torque-versus-speed curve when driven by a voltage. The intersection of the two curves is highlighted to show the operating point for each set of parameters, that is, the torque and the speed at which the fan-motor assembly turns for different rotor resistances and power supply conditions. Plot manufacturer’s torque-speed curves (based on the manufacturer’s electrical data). The load demand is achieved by changing the speed of the motor driving the system. An AC motor settles at an equilibrium speed when the motor output to the torque equals the load torque. Motors have changed. TRANSIENTS: At t=0, the motor is connected to a three-phase 460V AC grid, and the motor shaft speed is zero. Hence series motor is not suitable for applications requiring constant speed. VSD (Inverter) only provides speed change and the current to drive the motor. For the motor. Rated torque and rated speed are useful terms regarding the application’s torque and torque curve. Section: 2. Why RMS torque is important for motor sizing. The advantage of this type of inferred torque calculation is that no electrical or mechanical measurements, which may be quite costly, are needed. Dutro May 18, 1995 GMK30. One is a plot of … Mill Charge Load Calculation – Stone Crusher Machine in India …. A typical engine performance curve is shown below: Fig. The frequency range below the nominal frequency is called a constant flux range. It is possible that in such cases the T,, may be the highest torque developed by the motor in the entire speed range (Figure 2. Determine of the torque-speed curves for a DC motor 2. Performance curve. In other words, there is a tradeoff between how much torque a motor delivers, and how fast the output shaft spins. Whenever a current is supplied by means of a DC source, flux is produced which in turn interacts with the armature flux to produce a unidirectional torque. The motor load determines the operating point on the torque curve. For example in the curves below the speed torque curve for the CVK245AKCVK245BK stepper driver indicates that 24VDC is applied to the motor windings while the curve for the RKS545 stepper driver was created with 162VDC being applied to the windings. 6L V-8 to a clean-sheet, GM-built, Allison-branded 10-speed gearbox. The data is taken from the VEX wiki and the technique from this web page. T m = minimum, pull-in or pull-up torque. Each drive task requires a drive motor. A fan blade requires torque inan amount proportional to the square of the speed. zero at 0% speed, and. Note that both motoring and generating regions are plotted. The speed of the motor comes to zero, when the slip reaches to 1. The quadratic mechanical damping term produces a quadratic torque-speed curve. As we have already discussed the torque of the induction motor in the topic Torque Equation of an Induction motor. Torque Speed Curve of Series Motor. Continuous Power is defined as the product of the motor's continuous torque times the maximum rotational speed at that continuous torque. Variable voltage control 2. 76A of current. Performance curve. The required motor voltage v is read from the intersection of the prop and motor torque curves, and all the other motor parameters follow. The curve is for the wormgear output of the motor (the motor output shaft has a special wormgear pinion and carrier). The rotation region that provides maximum or high torque varies depending on the electric resistance, so changing the cage materials or geometry makes it possible to study the motor characteristics that most closely meet the goals of the design. Text: Slip speed varying according to the characteristic torque curve of the load Adjustable target , Figure 3. This would imply that torque is, if voltage is proportional to frequency, meaning constant applied ux, dependent only on absolute slip. The speed – torque curves are created by spinning a step motor up to a known speed and then gradually applying torque to the output shaft with a brake and measured with a torque transducer. These motors are designed for adjustable speed applications where up to 1000:1 constant torque speed range may be required. It was the couple’s Jaguar E-Type Zero, a classic E-type body fitted with a. 30, find the transfer function, G(s)-01(s)/ Ea(s). The normal running position is on the downward slope. Like pumps, motors produce a torque-speed curve of their own. The vector diagram for the split phase induction motor is shown in the Figure B. Power is speed times force (torque) if speed is low, power is low. It can be seen from figures 3 and 4 that the ratio of torque increase declines with increased current. 11 is typical of the simplest of control systems. If the overload or blockage is removed, the drive will resume its normal torque and speed. 4 is half the maximum speed, the torque-to-speed ratio is 2:1. 220; % Stator. Common features of interest are noted and discussed below. The graph above shows a torque/speed curve of a typical D. For example, if the minimum speed represented by point A on the power curve in Fig. standard designs with different torque–speed curves. for good load sharing of loads between motors, the torque-speed curve should have high regulation, Why ? f)Mention some of the drawback of conventional Ward-Leonard scheme over static Ward-Leonard scheme. Performance Curve. 2012912-The graph above shows a torque/speed curve of a typical D. Axis Name Here; Motor Parameters; Speed vs Torque. The drive starts and accelerates the motor smoothly as frequency and voltage are gradually increased to the desired speed. Actual rotation speed is 2~15% less than synchronous. High starting torque enables, even a small series motor to start a heavy load. Since the torque produced by a stepper motor decreases as speed increases, you will need to look at the speed-torque curve to determine if the stepper motor will work at that speed or not. Variable torque Must meet amperage rating of motor Constant torque Obtain the highest peak current readings under the worst conditions Check motor full-load amps (FLA) to see if the motor is already overloaded Starting torque modes High overload is 150% torque for one minute Breakaway torque allows 180% torque for 0. Peak or Obtainable Torque from small (FHP) Gearmotors and Motors It can get confusing when we discuss “Peak” or “Obtainable ” torque for small (fractional HP = less than 1HP/746W) gearmotors and motors because terminology and definitions sometimes change between AC and DC motors, gearmotors, or when a motor speed control is used. The maximum starting torque for constant volts-per-Hertz operation may actually be much less than full-load torque. AS2021-0D00. We later found through our lab experiments that K1 = 1432. of torque from 3,000 rpm to 6,000 rpm and over 375 lbs. Hi Duncan: An ideal DC motor's RPM is directly proportional to applied voltage. The total resistance is now 24 Ω and with a 12 VDC power supply, the motor will only get 0. The real motor curves are displayed two slides later (Note:Motor Horsepower (hp) = Torque x RPM) Torque - Speed Curve V/F curve In the figure the voltage and the frequency are varied at a constant ratio up to the base speed. Both devices are linked with a shaft so the speed is always identical. The type of connection decides the permissible loading at constant torque or constant power. Matthew DeBord/Insider The top speed is limited at 125 mph, and the 0-60mph run, according to Polaris and confirmed by yours truly, is about five seconds. Raising Voltage will raise the Watts a motor will produce but will not raise the current or amps that it can handle or flow through it. The simulink model used to get torque speed characteristic for a single phase half wave converter is shown in figure11. This curve can be superimposed onto the load speed torque curve, and provided the torque developed at all speeds exceeds the load torque, the motor will accelerate to full speed. The Shunt Motor also has a linear torque-speed characteristic and similarly-shaped power curve. The magnetization current IM flowing in the motor’s equivalent circuit (Fig. The driver generates torque action as a result of the difference between motor voltage and driver voltage, or incoming line voltage. Basically, in a series motor, the field winding is connected in series to the armature winding. I cannot find torque control with sensor lab in motorware from lab12a. Were it me, I would just use a VFD to change the speed with Vector Control to get the high torque capability out of a motor selected for the desired torque. The torque-speed curves for a stepper motor are developed with a specific motor-drive combination, operating voltage, and driving method. We later found through our lab experiments that K1 = 1432. This can also be described as the maximum speed of the motor. Brushed DC motor speed-torque curve (Kevin Lynch) Northwestern Robotics. Speed/torque gradient: A representation of the slope of the speed-torque curve (see graph below), approximately equal to the no load speed divided by the stall torque. This is the dynamometer GUI created by the Motor Torque Test Bench Team at UTD. At 60 hertz (base motor speed), both HP and torque are at 100 percent. ) plot the torque-speed curve for the motor. This is the stall torque—the maximum torque when the motor is running at nominal voltage. The motor toque T in N. Thanks to their flat design and high speed, these motors are particularly suitable for applications in the semiconductor industry or in laboratory analysis. armature current and (iii) Speed vs. Reason for this curve being defined with a (M 0 100K) to rated speed (M N 100K)with (M 0 100K) > (M N 100K) is that as the continuous operating speed of the motor would rise from zero rom to rated speed and beyond the continuous torque available decreases due to friction (bearings) and stator losses (mainly eddy currents) within the servo motor. This is the poster presented to the professor and peers summarize the experimental results of the project to replicate the Motor Torque-Speed Curve of an Arbitrary motor. 7 shows the. The most popular squirrel cage induction motor is of a 4-pole design. This is the dynamometer GUI created by the Motor Torque Test Bench Team at UTD. Squirrel cage motors are termed 'constant speed' because their steep characteristic in the operating region around full load results in large excursions in torque demand being accomodated by small variations of motor speed. BLDC motor is considered to be a high performance motor and is capable of providing large amounts of torque over a vast speed range. % First, initialize the values needed in this program. As the motor temperature rises, the no-load speed also increases. Figure 3-19 indicates a compound wound DC motor, with an associated speed/torque curve. If you look at your car's torque curve, you'll see that peak torque is held from 1700rpm to 5200rpm. On a hide speed cart you would want it less because it runs much faster. As the motor cools down, the speed will return to normal. At the synchronous speed slip (S)=0. Real-life motors have armature resistance and losses, which causes variation. Two fine motor options are available here: 2. Comparing this against a 300 Hp GM small V8 engine that makes 300 Hp at 5,000 and 375 Lb-Ft torque at 3200 rpm, this is a considerable difference. manufacturers publish motor data in the form of performance curves that show motor torque versus motor speed and motor torque versus current. If the load operates at 90% of maximum speed then the load will be 0. torque speed curve of crusher cone crusher versus motor speed. The curve for the output power of the motor is deduced from the graph of. 17H2049 Speed Torque Curve. torque [N · m] This Demonstration shows superimposed plots of the torque curves of a three-phase induction motor and that of a connected ventilation fan. The constant-speed unbalanced hoisting system operates in quadrants 1 and 4. Max power is 2. Figure 1 provides a graphical illustration of these changes. COURSE# - 18. armature current, (ii) Speed vs. Following this overview of the steps. Why RMS torque is important for motor sizing. 23H2045 Speed Torque Curve. A typical motor speed torque curve is shown in Figure 1. HomePRODUCTSArticles impact crusher torque speed curve hammer crusher speed chart cost cost of concrete crusher cost fuel crusher speed torque curve of crusher and motor - Gold Ore Crusher. Usually in rpm/V. For example in the curves below the speed torque curve for the CVK245AKCVK245BK stepper driver indicates that 24VDC is applied to the motor windings while the curve for the RKS545 stepper driver was created with 162VDC being applied to the windings. A servo motor torque curve depicts the amount of torque the motor can produce over its range of operating speeds. The main requirements for electric motors drives in EV, HEV and FCEV are wide speed range operation, high torque and fast speed response in low speeds and constant power in high speeds [1, 2, 4]. Since the torque produced by a stepper motor decreases as speed increases, you will need to look at the speed-torque curve to determine if the stepper motor will work at that speed or not. The slope of this straight line depends mainly on the rotor resistance. The motor speed for AC motors can be caculated with the Motor speed calculator. Below 35-40mph, you are torque limited. The high-speed DC Brushless motor can operate at 3200RPM, can generate up to 300 oz-in of continuous torque, and deliver as much as 700W, with the BLY34MDA4 offering. An AC motor settles at an equilibrium speed when the motor output to the torque equals the load torque. The torque-speed curves for a stepper motor are developed with a specific motor-drive combination, operating voltage, and driving method. The dotted lines on the torque/speed curve represent the portion of the curve not used by the drive. 17H2035 Speed Torque Curve. Title: msd 101 Subject: Motors and Actuators Created Date:. When the motor is started, the initial torque is about 250% of the rated torque. The torque-speed curve is similar for all centrifugal pumps due to simple math: the pump torque varies as the square of its speed. 14 shows how the motor torque-speed curve would change if rotor resistance is increased and all other parameters in the motor equivalent circuit stay the same. Depending on the motor design the maximum torque-to-. output torque Mx1 is permissible at a ratio of ix1. 11 is typical of the simplest of control systems. I’ve never seen anyone post the torque-speed curves the VEX motors so I thought I would take a shot at this even though it’s a bit out of my area of expertise. For simplicity, the fan torque curve is adjusted using a quadratic fit starting at. We went to Miramas, France to experience the 2016 7 Series and its latest technology. A Stepper motor has. At that point, the motor provides just enough current output to deliver the required torque. A motor is spun at free speed. But the motor torque is reduced as frequency increases. 23H2055 Speed Torque Curve. The speed-torque curve of an induction motor can be modified by an armature winding reconnected to give different sets of poles. Normal operation is to the right of the maximum torque (s < spo). That is generally the performance provided by many hobby motor-controller combinations. If not removed,. The flux φ produced by the stator is proportional to stator emf E 1. Model: VEC200 Voltage:48V/72V/96V Rated continuous current:80A Maximum phase current: 200A Motor control mode:FOC Driving method:Direct torque control Dimensions: 170mm(L) x 120mm(W) x 50mm(H) Weight:1. pdf), Text File (. The speed/torque curve shown in Figure 3-30 indicates the breakdown torque for a typical induction motor to be about 270% of the rated load torque. The 10L1000 comes with a list of. In some specially designed rotors, however, to achieve a high starting torque sometimes the pull-out torque Tpo may not be available on the speed-torque curve. Lego motor data can be found here:. 2-volt lithium cells. Motors have changed. The torque vs rpm curve for a motor is linear; with no load, the motor spins near Kv*V rpm. Figure 7–26 shows typical torque–speed curves for the four standard NEMAdesign classes. ” A large series resistance on the generator will. The operating point of a system is the intersection point of the torque-speed curve of drive and machine. RPM=K1*V where K1 is a constant, and V is applied volts. This is a better judge of the motor's performance as it's the motor's torque at speed. As we have already discussed the torque of the induction motor in the topic Torque Equation of an Induction motor. Current IM and hence Bnet are propor- tional to E1. regulation (speed stability) under a given load. That is generally the performance provided by many hobby motor-controller combinations. INDUCTION MOTOR TORQUE-SPEED CHARACTERISTICS Figure 6. View Profile. Here we have the typical speed-torque curve of the DC motor. To choose a motor that can meet the application requirements, it's important to ensure the application runs within the continuous duty zone during normal operation and does not exceed the intermittent duty zone when peak torque is required. Power determines the efficiency of. Then as speed continues to increase, the torque increases until it peaks at the breakdown torque, sometimes called the pull out torque. This type of motor is used whenever speed regulation cannot be obtained from either a series or shunt wound motor. So, how does Tesla changes them? Do we have any curves (like rpm/power/torque) that describe it? View attachment 220188. The speed-torque requirements for three fan blades are shown drawn on top of the motor speed-torque curve. We used dynamometer with hysteresis brake to load the motor. At 60 hz (base motor speed), both HP and torque are at 100%. The total resistance is now 24 Ω and with a 12 VDC power supply, the motor will only get 0. The pull-out (maximum torque) decreases to about 40% of its original value, and the motor develops no starting torque at all. This graph indicates that when the engine speed reduces to 60%, the engine torque increases 140% and when the engine speed reduces to 40%, the engine torque increases 160%. Torque-speed curve implied by an equivalent circuit Based on the torque equations developed in the previous section for the single cage and double cage motor models, torque-speed curves can be constructed from the equivalent circuit by calculating the torque at each point on the full range of motor speeds (i. The objective is to provide torque vs speed curves as shown below. The maximum starting torque for constant volts-per-Hertz operation may actually be much less than full-load torque. If you have a 10,000 RPM spindle motor and the torque drops from it's constant peak at 8200 RPM, then 8200 RPM would be the. Torque-Slip Characteristics The curve drawn between torque and slip from start (s=1) to Synchronous speed (s=0) is called torque slip characteristics of the induction motor Torque Equation Input voltage is constant (E2=C) Kongunadu college of Engineering & Technology Three phase Induction Motor – Torque slip characteristics. These motors are designed for adjustable speed applications where up to 1000:1 constant torque speed range may be required. As discussed earlier, in a BLDC motor, the torque remains constant for a speed range up to the rated speed. It is shown that the current will vary differently from the first power of the voltage; and the torque differently from the square of the voltage. Servo motor torque curves are relatively flat up to the motor's maximum speed, unlike stepper motors, whose torque drops sharply beyond a certain operating speed. In the first Cartesian dial are shown the Torque, in [Nm] (X axis), the rotation speed, in [Rpm] (Y1 axis), the current consumption in [A] (Y2 axis), the efficiency (Y3 axis). values will determine the output torque, motor speed, and the resulting output power at any point on the motor curve at a given terminal voltage, as well as the overall slope of the motor curve. The speed-torque curve for other driven equipment's such as pumps, fan, blowers will also follow the same below rules only. The Synchronous Speed of an AC Motor Is the Speed of the Rotating Magnetic Field Set up by the Stator Winding Synchronous Speed (RPM) = (120 X Frequency) Divided by the Number of Poles. Most automotive engines produce useful torque output within a narrow band of the engine's entire speed range. Air drag is even worse, proportional to the square of the speed. Figure 1 - Torque typical curves. It is combined with a seven-speed, automatic. The speed-torque curve for other driven equipment's such as pumps, fan, blowers will also follow the same below rules only. The speed-torque curve is expressed by the following equation (N as speed, T as torque):. Variable torque Must meet amperage rating of motor Constant torque Obtain the highest peak current readings under the worst conditions Check motor full-load amps (FLA) to see if the motor is already overloaded Starting torque modes High overload is 150% torque for one minute Breakaway torque allows 180% torque for 0. In an actual application, this curve has to be shifted to account for the load inertia. The full-load torque of the 1765 RPM 30 HP motor is 89. The torque slip curve for an induction motor gives us the information about the variation of torque with the slip. Torque and speed of rotation The torque generated by the motor, and its speed of rotation, are dependent on each other. attached to the bacterial body. The only part of the curve, which is almost linear, is good for operation. While these motors may work for a given application, a little homework maybe needed to verify whether the motor will work in reduced voltage mode. speed curve shown below. More complex control systems sometimes introduce electronic resonances that act to increase the available torque above the motor's low-speed torque. In this site, you will find a listing of products offered by the participating companies. The blue dot in this curve represents the torque required at the speed required for our example application. Of course the electric motor speed should approximate the maximum running speed of the load. At lower speeds, such as might happen when load is added, motor torque is higher than load torque and the motor will accelerate back to the point of equilibrium. Variable Frequency Drives (VFD's) • Popular speed control devices used in industrial, commercial Torque-Speed Curve • Amount of Torque produced by motors varies with Speed. Figure 1 showed a plot of induction motor torque vs speed from zero to synchronous speed. Can it be considered a constant speed machine?. The speed-torque curve for other driven equipment's such as pumps, fan, blowers will also follow the same below rules only. As I know, there is no gearbox on Model S and the ratio in the gear unit is constant. As the motor accelerates, the torque output reduces until it hits the pull up torque. the torque required at low speed is very low but the torque required at high speed is very high. The Induction Motor torque-speed curve is typical of this type of motor having a low starting torque, and a peak torque just below synchronous speed. Notice that the single phase curve, unlike its three phase cousin, consists of only one wave form. MATHEMATICAL MODELING AND SPEED TORQUE ANALYSIS OF THREE PHASE SQUIRREL CAGE INDUCTION MOTOR USING MATLAB SIMULINK FOR ELECTRICAL MACHINES LABORATORY N (8) Where Ns = synchronous speed of motor f = Supply frequency = 50 Hz p = no. Figure 12 shows the typical torque-speed curves of a three-phase motor when it is running normally and when it is single. Load Torque: For a fixed voltage, the speed of the motor is inversely affected by the load. Explore the many sources of news, expert opinion and customer perspectives from the largest company in the world dedicated to industrial automation and information. Synchronous Motor Torque-Speed Characteristic Curve Synchronous motor provides power to such loads that operate at constant speed and system. The maximum torque will come at a point where the combination of. This is created by running through breakdown to locked rotor and then back to full speed in a very controlled manner. Rated torque is the maximum torque a motor can produce continuously and rated speed is the top. So let's take that, and it's torque curve puts it at 6. So we can say that in order to understand the running behavior and implications of any type of torque DC motor we must deeply look at the torque equation of a DC motor. We used the following equation for Torque. That is generally the performance provided by many hobby motor-controller combinations. AKM Performance Curve Generator Request Quote. The curves were recorded with "open loop" controlled operation and "vector control" field-oriented control. is 1000 rpm; – current at rated speed is. look at the tesla torque and power curve. The image shows a typical motor torque curve and a hypothetical load torque curve superimposed. As we have already discussed the torque of the induction motor in the topic Torque Equation of an Induction motor. After all, its HP that will determine the "Torque" at the rear wheels at any vehicle speed. Figure 1 provides a graphical illustration of these changes. One of the main variables that sends a torque curve descending after its peak is the difficulty of forcing air into the engine. These are explained below for each type of DC motor. We used the following equation for Torque. The pull-in torque curve shows the maximum friction torque with which the motor can start, at different stepping rates, without losing any steps. DC motor electrical and mechanical power in the speed-torque plane (Kevin Lynch) Motor Torque, Speed and Current. You must observe that as the RPM increases, both the curve become steeper. Normally an induction motor operates at 90-97% of the synchronous. The torque slip curve for an induction motor gives us the information about the variation of torque with the slip. It is actually the slope of our torque curve. So, how does Tesla changes them? Do we have any curves (like rpm/power/torque) that describe it? View attachment 220188. It contained 2 poles per phase for a total of six. 05 X Percent Torque. Note that speeds correspond to slip values greater than 1, and speeds greater than 1500 rpm correspond to negative slip. The curves are valid for a brushless DC (BLDC) motor to the extent that the BLDC motor controller makes the motor perform like a brushed motor. The torque on the motor is then dependent on how loaded the motor is. Curve Descriptions: Motor(1) Test 1 Run 208V 60 Hz 4P Filtered Data SPEED vs TORQUE SPEED vs WATTS SPEED vs ILine 10 20 30 40 50 60 70 80 90 Oz-Ft 400 800 1200 1600 2000 2400 2800 3200 3600 WATTS 2. The motor then drives the blower at constant speed and just delivers the torque required by the load. Torque -Speed curve. Once you hit max power, the motor continues to spin faster, but the torque decays exponentially. Performance Curve. While for 160V starts at. But the motor torque is reduced as frequency increases. (A stepper motor on the other hand can have a significant ramp where the torque drops off considerably as the speed gets higher. 0% for standard Design B torque curve induction motors. 350 SBC bored 30 over, aluminum heads, Holley 650 Double pumper carb, fully rollerized motor with 3 hours on it. The readout was something like 500amps stall. If you have a 10,000 RPM spindle motor and the torque drops from it's constant peak at 8200 RPM, then 8200 RPM would be the. The speed-torque curve is expressed by the following equation (N as speed, T as torque):. over the entire speed range under different loads are the basis for the curve progression of torque, output and specific fuel consumption. Experiment 7 Series DC Motor (I) Objectives • To determine the torque-speed characteristic curve. The term (sX 20) 2 becomes large. I can't see the point of having lots of torque below this or a sudden peak at say 4000 rpm. 1tl_d1ml10122 37 6 380 50. Note that both motoring and generating regions are plotted. T = -K1*w + K2. energy savers Improving industrial productivity through energy-efficient advancements In addition to the running torque power/speed relationships just discussed, consideration must also be given to torque/power re quire-ments for start-up and acceleration of these loads. Nidec Motor Corporation trademarks followed by the ® symbol are registered with the U. The figure below shows the motor characteristic curves of a typical DC motor (brushed!). The 'shaft' torque, which is the usable output torque of the motor, will always be less than the electromagnetic torque due losses in the system. Performance Curve. Therefore maximum torque formula for induction motor is as follows: The above expression indicates that. The speed-torque curve is expressed by the following equation (N as speed, T as torque):. The correct sizing of the variable frequency drive (VFD) system depends on the knowledge of the behavior of the load type, that is, how the load is related with speed and consequently how much torque is demanded on the motor shaft. The Induction Motor torque-speed curve is typical of this type of motor having a low starting torque, and a peak torque just below synchronous speed. In the legend the speed values will be displayed. The motor speed for AC motors can be caculated with the Motor speed calculator. We later found through our lab experiments that K1 = 1432. Table 1: General requirements for a PMSM used in EMB application in Automotives Parameter Units Value Peak stall torque Nm 3. Motor characteristic curves of a brushed DC motor. In a ideal system with no friction, the torque to maintain 10 m/s and 1000 m/s is the same, but the power required to produce that torque at the higher speed is 100 times more. PolyU - BSE Induction Motors - Principle Operation and Torque-speed Curve. If load torque exceeds the breakdown torque, the motor will stall. Let's look at a typical torque speed curve for an AC induction motor. Both devices are linked with a shaft so the speed is always identical. It will be in stand still This curve also gives maximum torque the motor can develo. The Synchronous Speed of an AC Motor Is the Speed of the Rotating Magnetic Field Set up by the Stator Winding Synchronous Speed (RPM) = (120 X Frequency) Divided by the Number of Poles. The torque supplied by the motor also varies during starting. The current that goes along with this toruqe is the current that would align with any given torque on a motor speed vs torque curve and speed vs current curve. If the drive lowers frequency it is lowering voltage, and if the power consumption/torque doesn't drop proportionally for some reason, the current draw will increase For example, lowering the frequency of the drive will lower the voltage, but if the motor is not synchronized it will force the amperage draw to. Torque - speed curves are generated by plotting motor speed, armature current, mechanical output power, and efficiency as functions of the motor torque. Torque Speed Curve For Johnson KC 613L Motors. If the motor is run outside of this curve, it will stall. Horsepower = speed (RPM) x torque (ft-lbs) / 5252. At that point, the motor provides just enough current output to deliver the required torque. Above the corner speed, motor current is limited by the motor’s inductive reactance. cone crusher torque speed curve cone crusher versus motor speed the crusher, induction motor for crusher load hp series cone crusher while a full gyratory. 48V800W Length: 165 mm 88 kgs. With a shunt motor, the speed doesn't change much when the load changes. torque speed curve of crusher cone crusher versus motor speed. Motor speed (n): Motor speed in RPM. txt) or view presentation slides online. The speed, torque and controllability of each motor must fulfill the requirements of the task. The engine delivers 302 horsepower and 273 lb-ft of torque and an automatic start/stop system for shutting down the engine to optimize fuel economy. Using hall sensor feedback, the DC Brushless controller operates in a constant velocity mode. This motor has a starting torque of 0,60 pu and a pull out torque of 2,33 pu. This curve can be superimposed onto the load speed torque curve, and provided the torque developed at all speeds exceeds the load torque, the motor will accelerate to full speed. Torque Slip Characteristics of Three Phase Induction Motor. Mechanical designers frequently create systems designed to use stepper motors at relatively high rpm based on the maximum motor speed rating (often 3000 rpm) and the motor torque vs. Once the maximum torque current and advance angle are determined the torque-speed characteristic and some other important parameters of the Prius motor can be obtained using the D-Q Analysis of MotorAnalysis-PM. Power (hp)=[ Motor Speed(rpm) × Torque (lb-ft) ] ÷ 5252 We could learn that a bigger power could have a bigger motor speed and torque, but a bigger motor speed not implies a bigger torque. A fan blade requires torque inan amount proportional to the square of the speed. It can be seen from figures 3 and 4 that the ratio of torque increase declines with increased current. An important characteristic of most induction motors is speed- or slip-torque curve. The number of torque changes based on a given speed of the load. Generate Curve. Introduction A series dc motor is a motor whose filed windings consists of a relatively few turns connected in series with the armature circuit. That is generally the performance provided by many hobby motor-controller combinations. As the motor picks up speed, torque decreases slightly to the lowest point shown on the curve above. • High Speed Capabilities up to 7500 rpm on some models. Estimate of the armature resistance (Ra), torque constant (ka) and back EMF constant (kb) for the motor from your measurements 3. The breakaway torqueis required to start a load from rest (to overcome the. The required motor voltage v is read from the intersection of the prop and motor torque curves, and all the other motor parameters follow. From this diagram you can see that the speed of the shunt motor stays fairly constant throughout its load range and drops slightly when it is drawing the largest current. Lets take a look at the motor stator that utilizes this power source. Operating a motor overloaded for an extended period of time will cause an excessive heat buildup in the motor and may eventually burn up the motor windings. The speed-torque requirements for three fan blades are shown drawn on top of the motor speed-torque curve. For example: Max. Abstract: This study presents analysis and effects of rotor faults in squirrel cage induction motor on the torque-speed curve. For an arbitrarily selected single-phase induction motor, a curve of speed at breakdown torque as a function of r 2 /X is also included for the purposes of illustration and understanding. In petrol engines, it characteristically starts at around 1000-1200 rpm and reaching a peak in the range of 2,500-4,000 rpm. Figure 3-19 indicates a compound wound DC motor, with an associated speed/torque curve. surplusjohn. To increase torque by 20%, increase. Figure 4 illustrates the linear nature of the torque-versus-speed. This point is called peak power. Slip in this motor is the amount the motor runs slower than the actual frequency would normally drive the motor. Neglect the stator resistance and rotational losses. 12, “Constant Horsepower Winders” for more detailed description of this type of operation. of poles of motor = 4 After this we measure the speed of rotor at each load by using stroboscope explained. A torque/speed curve plots the torque of a motor against the speed the motor is going at. Both X13 and variable speed motors are DC (or alternating DC if you prefer), 3 phase, permanent magnet rotor motors that use back EMF to determine motor torque and adjust to load conditions. The hybrid stepper motor combines the best features of both the PM and VR type stepper. The speed torque curve of an induction motor is a plot of speed on the x-axis and torque on the y-axis. Let's look at a typical torque speed curve for an AC induction motor. Any motor torque load above the breakdown torque. From these curves, it is clear that, beyond the point of maximum torque, the increased load on the motor results in a decrease in torque developed. Artificial Lift Chemical, Oil & Gas Industries. The upper curve represents the maximum torque which the motor can develop at a given pulse rate or alternately, the maximum rate to which a given load can be accelerated (pull-out). So if the voltage is changed the speed-torque curve is also changed but remains parallel to the initial curve before the voltage was changed. Derive thx1 x2 k2 k1 m1 m2 c1. 7) creates the net magnetic field Bnet. By itself, an induction motor has a predictable torque curve, but this curve is not suitable when a specific speed and torque are required. Speed Torque Curves For Stepper Motors. If the motor is run outside of this curve, it will stall. An 1800 rpm motor can be run safely up to 120 Hz or 200% of its rated speed but…as the accompanying graph indicates, at double speed, the motor can only operate with 25%. As a general rule, the application determines the drive. The torque slip curve for an induction motor gives us the information about the variation of torque with the slip. Typically, selecting a motor based on the total required torque and max required speed is a safe bet even though the motor may not need that torque at its. At the point of equilibrium, the torque produced by the motor is equal to the amount of torque required to turn the load at a constant speed. Curve Descriptions: Motor(1) Test 1 Run 208V 60 Hz 4P Filtered Data SPEED vs TORQUE SPEED vs WATTS SPEED vs ILine 10 20 30 40 50 60 70 80 90 Oz-Ft 400 800 1200 1600 2000 2400 2800 3200 3600 WATTS 2. Only two parameters related to break-down torque and break-down slip are regarded as input parameters. Thus, it may be assumed that the motor will average. full load rating, and or rated speed. One example is the large ball mill used in minerals processing. Press release - Market Industry Reports - Electric Power Assisted Steering (EPAS) Market 2019 Share, Trend, Segmentation and Forecast to 2030 - Robert Bosch, JTEKT, DENSO - published on openPR. Not suitable for constant-torque load. So the torque vs. ) repeat (b) with 75% reduction from rated. The step time t is the time it takes the motor shaft to rotate one step angle once the first step pulse is applied. Motor speed (n): Motor speed in RPM. Unit-7- Control of Slip Ring Induction Motor, Topic -: Effect of Rotor Resistance of Induction Motor on Torque Speed Curve #RTU #videolecturenotes #aryacollege #aryagroup #maincampus #. rms, line-line. Generally, three characteristic curves are considered important for DC motors which are, (i) Torque vs. Below a certain speed, called the corner speed, current would rise above the motor's rated current, ultimately to destructive levels as the motor's speed is reduced further. 3 shows that the torque/speed curve shifts to the right as frequency and voltage are increased. The torque slip curve is a straight line. The optimum torque and speed are half the Ts and Wn respectively. Speed Torque Curves For Stepper Motors. a motor, the output speed is proportional to the flow through the unit. The Universal Motor torque-speed characteristic follows 1/x^2 relationship. The relationship of torque and horsepower to speed on "variable torque" loads are shown in Figure 2. 1 Motor speed-torque curve Refer to Figure 2. Figure 3 shows a Thevenin's equivalent of the stator. heavy industry is specialized in the design,. At 60 hertz (base motor speed), both HP and torque are at 100 percent. While these motors may work for a given application, a little homework maybe needed to verify whether the motor will work in reduced voltage mode. Motor Calculations • Calculating Mechanical Power Requirements • Torque - Speed Curves • Numerical Calculation • Sample Calculation • Thermal Calculations Calculating Mechanical Power Requirements Physically, power is defined as the rate of doing work. These motor data are best thought of as theoretical performance curves, because they are produced from calculations of motor input (current), motor efficiencies, and other. The variations in the motor Speed, Torque and Power at no load torque and full load torque have been analysed. 6L V-8 to a clean-sheet, GM-built, Allison-branded 10-speed gearbox. Soft starters also precisely control the starting and stopping of IE3 motors, offering control over acceleration and deceleration to cater for motors with tough torque curves. Speed Torque Curves All speed / torque curves below are generated using 8:1 microstepping setting on driver. By changing the machine's inputs or its parameters, we can influence its behavior. If load torque is larger than this the machine can not accelerate. The full-load torque of the 1765 RPM 30 HP motor is 89. Mathematically, the torque requirement is a function of the speed squared and the horsepower is a function of the speed cubed. OUTPUT SHAFT With Sprocket To Drive Chain: Medium speed high torque brushless motor High energy efficiency Light weight Voltage:36V-60V Power Rate:500W-1000W. Figure 1 provides a graphical illustration of these changes. We used dynamometer with hysteresis brake to load the motor. Air drag is even worse, proportional to the square of the speed. zero at 0% speed, and. For example in the curves below the speed torque curve for the CVK245AKCVK245BK stepper driver indicates that 24VDC is applied to the motor windings while the curve for the RKS545 stepper driver was created with 162VDC being applied to the windings. Quickly optimize your frameless motor option by adjusting current, voltage, ambient temperature and winding factors for best performance to match your needs. BLDC Motor for Electric trikes : 48V500W Length: 98 mm 6 kgs. Characteristic torque and speed curves For the design of your application. Servo motors generally have a relatively flat speed torque curve in that the amount of torque the motor has available stays relatively constant up until you reach the maximum speed of the motor. Therefore K1 can be defined as the coefficient of proportionality. 6 liters/100 kilometers (36 mpg US). As a general rule, the application determines the drive. Rated torque and rated speed are useful terms regarding the application’s torque and torque curve. Mostly this motor is connected with large power systems so these power systems behaves like large infinity bus bars for motor and the variation in motor has no effect on these bus bars. For example, if the minimum speed represented by point A on the power curve in Fig. surplusjohn. What's special about the wound-rotor motor? This type of 3-phase induction motor has high starting torque, which makes it ideal for applications where standard NEMA design motors fall short. S curve function S curve can improving the impact during the start and stop processing, it is very useful in crane, elevator application. This simulation generates the speed-torque curve for a 3 HP 460V AC Induction Motor. These curves are generated by plotting motor speed, consumed current, and efficiency as functions of the motor torque. From this diagram you can see that the speed of the shunt motor stays fairly constant throughout its load range and drops slightly when it is drawing the largest current. Free running : During this period the motor develops enough torque to overcome the friction and wind resistance and hence the locomotive runs at constant speed. Torque/Speed Characteristic Under Load As stated earlier, stable operation of an induction motor lies over the linear portion of its torque/ speed curve. Text: Slip speed varying according to the characteristic torque curve of the load Adjustable target , Figure 3. speed curve will be pushed out at higher speeds. % Get the magnetization curve. In this case, the relatively large starting torque is achieved with realistic current values. As was mentioned earlier, the speed - torque characteristics are determined by the stepper motor and driver combination. The required motor voltage v is read from the intersection of the prop and motor torque curves, and all the other motor parameters follow. The stepper motor is a decent solution, with almost constant torque in low speed (don;t forget max speed is just 0. Motor torque /Speed characteristic are very important, because the motor provides the torque that the load requires and not the VSD. 350 SBC bored 30 over, aluminum heads, Holley 650 Double pumper carb, fully rollerized motor with 3 hours on it. The pull-in torque curve shows the maximum friction torque with which the motor can start, at different stepping rates, without losing any steps. 5 kW from the motor (the motor's rated power) at its rated speed. As the slip increases, the speed of the motor decreases with the increase in load. This curve can be superimposed onto the load speed torque curve, and provided the torque developed at all speeds exceeds the load torque, the motor will accelerate to full speed. 8° Step Angle. T = -K1*w + K2. The correct sizing of the variable frequency drive (VFD) system depends on the knowledge of the behavior of the load type, that is, how the load is related with speed and consequently how much torque is demanded on the motor shaft. Better yet, the powertrain warms up quickly so it can operate at peak efficiency. When the motor is started, the initial torque is about 250% of the rated torque. Common features of interest are noted and discussed below. The ZD Series of Stepper Motor Controllers can be run using a range of external inputs, offers 25600 potential positions (on a standard 200 step stepper motor) and can be programmed to do virtually anything! However, as the above torque speed graph highlights, an increase in speed leads directly to a drop off in the torque available from the motor and controller. FIGURE 1 Induction motor torque-speed characteristic curves. For example in the curves below the speed torque curve for the CVK245AKCVK245BK stepper driver indicates that 24VDC is applied to the motor windings while the curve for the RKS545 stepper driver was created with 162VDC being applied to the windings. A torque/speed curve plots the torque of a motor against the speed the motor is going at. * Note: the actual characteristics will vary depending on the test stepper drive. 1981 Chevrolet Camaro z28 Original 4 speed car, floors and trunk all original and solid New carpet, seats, SS rims original powder coated, new competition clutch, new mini high torque starter. INDUCTION MOTOR TORQUE-SPEED CHARACTERISTICS Figure 6. On a hide speed cart you would want it less because it runs much faster. However, when the pump is at rest—0% full load speed—the full load torque is never also 0%. Why RMS torque is important for motor sizing. LMC Poised for Major Growth. Diesels seem so quick because they have relatively flat torque curves. the output power versus speed curve of the motor in Problem 7-7. As the load increase beyond the capability of the induction motor, the slip increases and you move up the torque curve. The motor can be run up to the maximum speed, which can be up to 150% of the rated speed, but the torque starts dropping off. Hence the characteristic is straight line from point A to point B. All of these parameters are to be computed at 120 V. I’ve never seen anyone post the torque-speed curves the VEX motors so I thought I would take a shot at this even though it’s a bit out of my area of expertise. from standtill to synchronous speed). Looking closely, we can see an interesting phenomenon with the hot motor curve. INDUCTION MOTOR TORQUE-SPEED CHARACTERISTICS. 23H2045 Speed Torque Curve. Target audience: Engineers, mechanics, winders and sales persons with. torque [N · m] This Demonstration shows superimposed plots of the torque curves of a three-phase induction motor and that of a connected ventilation fan. (2) In SI units, the motor torque and back emf constants are equal, that is, ; therefore, we will use to represent both the motor torque constant and the back emf constant. The data is taken from the VEX wiki and the technique from this web page. Base RPM is 1800, if torque is constant, then the torque/speed curve is a straight line. Jul 27 2015One tool for servo motor selection is the torque-speed curve which depicts the motor's continuous and intermittent operating zones Because the servo amplifier can limit the motor's peak speed and torque it's important to note that torque-speed curves are often based on specific motor and amplifier combinations. If the overload or blockage is removed, the drive will resume its normal torque and speed. VEX Robotics motor curves were developed experimentally using a "down-up" dyno test. For example in the curves below the speed torque curve for the CVK245AKCVK245BK stepper driver indicates that 24VDC is applied to the motor windings while the curve for the RKS545 stepper driver was created with 162VDC being applied to the windings. Motor rated torque: 98. - For completeness, only in this graph, is represented also the output power curve in[W] (Y4 axis). A Nidec Group Company. Why RMS torque is important for motor sizing. Thermal limits can also be altered by changing the motor environment or adding passive or active cooling to the motor housing. Insert the denominator of reduction ratio in of gearhead model name. The VFD starts the motor at a frequency at which the motor provides about 150% of rated torque using only the solid-line part of the torque speed curve. This can also be described as the maximum speed of the motor. To each Torque value corresponds a value of current and speed. For the motor. Under the hood of the 2020 Chevy Silverado 2500 LTZ, General Motors matched its Duramax L5P 6. DC motor electrical and mechanical power in the speed-torque plane (Kevin Lynch) Motor Torque, Speed and Current. The motor load determines the operating point on the torque curve. The following discussion will describe the construction of a set of torque - speed curves for a typical DC motor from a series of raw data measurements. include two-speed motors, adjustable speed drives, and load management strategies that maintain loads within an acceptable range. Soft starters also precisely control the starting and stopping of IE3 motors, offering control over acceleration and deceleration to cater for motors with tough torque curves. The load torque should be between 75%-100% of the rated motor toque with 95% being an ideal choice. Continuous stall torque is the motor's continuous torque at 0 speed (at stall). Asynchronous motors are the most widely used electrical motors due to their reliability, low cost, ruggedness and robustness. For a distinctive induction motor, the pull-out torque on the curve will be TWO hundred % of the evaluated torque at full load of the motor, and the starting torque of motor will be one fifty %. Rated torque is the maximum torque a motor can produce continuously and rated speed is the top. The linear region of operation for 240V approximately starts at TL = 30 N. The maximum generated torque ranges from 250% to 350% of the rated torque (see Figure 9 for torque-speed curve). speed curve shown below. SureServo Systems DO NOT provide maximum torque AT maximum speed - select a motor/gearbox combination (above) to see the specific torque/speed curve. zero at 0% speed, and. For the above graph, peak power occurs at 1500 rpm and 5 ft-lbs of torque; 1. So let's take that, and it's torque curve puts it at 6. The difference, or "slip," between actual and synchronous speed varies from about 0. Baldor Products Improve Reliability. 3 - Typical torque-speed and current-speed curves (a - standard motor, b - high torque motor (6 per cent slip)) The curves in Fig. What does the torque / speed curves look like on them? I would also likely need to replace the bearings on the spindle, additional cost. Evaluate the possibility of liquid cooling option to improve continuous torque capabilities. 0L EcoBoost engine providing 250 hp and 280 lb. A servo motor offers an additional time-dependent peak torque rating, a more flexible speed curve, and higher performance but a properly sized stepper motor could help you realize a better cost savings over a servo. include two-speed motors, adjustable speed drives, and load management strategies that maintain loads within an acceptable range. As you can see from the graph speed and current are linear functions of torque so you might need only two measurements to draw these graphs. Figure 12 shows the typical torque-speed curves of a three-phase motor when it is running normally and when it is single. It was the couple’s Jaguar E-Type Zero, a classic E-type body fitted with a. The torque curve and power curve for a constant-torque spindle. torque speed curve of crusher cone crusher versus motor speed. The motor load determines the operating point on the torque curve. A 24 VDC generator (actually just another DC motor) is used as the mechanical “load. BLDC motor is considered to be a high performance motor and is capable of providing large amounts of torque over a vast speed range. The torque slip curve for an induction motor gives us the information about the variation of torque with the slip. This webinar covers: Starting torque Breakdown torque Full load torque Speed current curve Load torque curve Impact of reduced voltage start (autotransformer, PWS, wye-delta) Slot combination problems (noise, torque cusp, cogging) It is very important to understand speed torque curves and how they impact motor operation. This is because the flow of magnetic flux changes, as seen in figures 1 and 2. revolutions per minute [rpm], foot-pounds of torque and amperes). Working amicably with a seven-speed automatic transmission and aided by the electric motor, response is sharper than the GLC 300 and 0-60 takes about 5. What does the torque / speed curves look like on them? I would also likely need to replace the bearings on the spindle, additional cost. most it should be operating at torque and speed of maximum power. The Torque speed curves with variable stator voltage [3] control are shown in Fig 3. The X axis is motor speed from 0 to 120 hertz. By reading the curve, you can confirm that the motor will provide enough torque over the speed range in your application. The speed-torque curve of an induction motor can be modified by an armature winding reconnected to give different sets of poles. Mechanical designers frequently create systems designed to use stepper motors at relatively high rpm based on the maximum motor speed rating (often 3000 rpm) and the motor torque vs. Known variables: Weight (lbs), Linear Velocity (ft/min), Speed of Driving Motor (RPM), Change in Speed (RPM), and Time to Accelerate Total System (sec) In addition to the torque required to drive the load at a steady speed, torque is required to accelerate the load. Motor speed-torque curve Pull-out, breakdown or maximum torque, obtainable over the entire speed range.