Electric Motor Torque Rpm Curve

Figure 1 provides a graphical illustration of these changes.

Electric motor torque rpm curve.

The honda s2000 on the other hand has decent power 265 whp but low torque at just 163 lb ft. One is a plot of empirical data and the other was plotted mechanically using a device developed at mit. N revolution per minute rpm alternatively. The shunt motor also has a linear torque speed characteristic and similarly shaped power curve.

Like pumps motors produce a torque speed curve of their own. T ftlb torque lb f ft. The engine is designed to make peak power and peak torque at very high rpm above 8 000 versus zero. In this overlay the shaded area reflects the accelerating torque available from the motor to drive the pump.

The roadster s redline is 14000 rpm. Introduction of a vfd when the speed of an ac motor is controlled by a vfd hp or torque will change depending on the change in frequency. P hp horsepower delivered by the electric motor hp. Full load torque is developed with the motor operating at rated voltage frequency and load.

Other electric motors may in fact produce maximum torque throughout their entire operating range. 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. T inlb torque in lb f. At full load torque the speed of the electric motor is slightly less than the synchronous speed as shown in the curve above.

That is why the shaft and frame of a 900 rpm motor are usually larger than those of an 1 800 rpm motor of the same hp. 1 ft lb f 1 356 nm. The dc motor has a linear torque speed characteristic and power peaks at about half the maximum rpm. Motor torque speed curve is a very good approximation.

As a current flows through the electric motor a related electrical charge causes an armature to rotate. For example the ac motor found in the tesla roadster 2008 produces near constant maximum torque from 0 to about 6000 rpm while maximum power occurs at about 10000 rpm long after torque begins to drop off. The linear model of a d c. Torque in imperial units can be calculated as.

The torque speed curves shown below are actual curves for the green maxon motor pictured at right used by students in 2 007. In practice a shunt motor cannot run at its peak power or torque as the currents involved are too large. Full load torque flt the torque required to produce rated power at full load speed. T inlb p hp 63025 n 1.