Electric Motor Torque Speed Curve

The torque available at this point is called pull up torque.

Electric motor torque speed curve.

Normally at it s top at operating speed. The linear model of a d c. The torque is the twisting force that makes the motor running and the torque is active from 0 to 100 operating speed. Note that the characteristic torque speed curve for this motor is quite linear.

As seen full load speed is 1728 rpm and full load torque is 45 n m point a whereas breakdown torque is 150 n m and locked rotor torque is 75 n m. Common features of interest are noted and discussed below. One is a plot of empirical data and the other was plotted mechanically using a device developed at mit. We can derive an equation from the equivalent circuit that allows the calculation of the torque for a given value of slip.

Zero at 0 speed and. Figure 1 showed a plot of induction motor torque vs speed from zero to synchronous speed. Note that both motoring and generating regions are plotted. Like pumps motors produce a torque speed curve of their own.

Torque speed plots in the motoring region. For every motor there is a specific torque speed curve and power curve. Motor torque speed curve is a very good approximation. The servomotor is a controlled servomotor with a maximum torque of 0 25 nm.

Note that torque is inversely proportioal to the speed of the output shaft. The motoring region of the induction machine torque speed curve is the region of greatest interest. The full torque from zero speed is a major advantage for electric vehicles. In other words there is a tradeoff between how much torque a motor delivers and how fast the output shaft spins.

The y axis is the percent of hp and torque. The plots below show a number of different torque speed curves due to differences in the motor designs. As the motor picks up speed torque decreases slightly to the lowest point shown on the curve above. 34 23 a shows the torque speed curve of an 11 kw 440 v 60 hz 3 f scim.

The x axis is motor speed from 0 to 120 hertz. This curve is called the torque speed characteristic curve. By overlaying the torque speed curve of a pump and a motor one can verify that the motor is producing enough accelerating torque to drive the pump to full speed as shown below. When the vfd reduces frequency and motor speed it also reduces voltage to keep the volts hertz ratio constant.

Figure 1 induction motor torque speed characteristic curves. Pull up torque put this term is used for the lowest point on the torque speed curve for an electric motor which is accelerating a load up to full speed. 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. At 60 hertz base motor speed both hp and torque are at 100 percent.