Electric Motor Rpm Torque Curve

Thankfully in electric motors maximum torque is produced from the get go.

Electric motor rpm torque curve.

Electrical motor power velocity and torque equations. The speed torque curve is expressed by the following equation n as speed t as torque. The linear model of a d c. The torque speed curves shown below are actual curves for the green maxon motor pictured at right used by students in 2 007.

In this overlay the shaded area reflects the accelerating torque available from the motor to drive the pump. This is the opposite coefficient of the linear speed torque curve. As a current flows through the electric motor a related electrical charge causes an armature to rotate. Torque in imperial units can be calculated as.

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. T inlb torque in lb f. 1 ft lb f 1 356 nm. Other electric motors may in fact produce maximum torque throughout their entire operating range.

Steam engines and electric motors tend to produce maximum torque close to zero rpm with the torque diminishing as rotational speed rises due to increasing friction and other constraints. T ftlb torque lb f ft. 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. Like pumps motors produce a torque speed curve of their own.

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. P hp horsepower delivered by the electric motor hp. The roadster s redline is 14000 rpm. Motor torque speed curve is a very good approximation.

Figure 1 provides a graphical illustration of these changes. T ftlb p hp 5252 n 1b. Relationship between torque power and energy. T inlb p hp 63025 n 1.

One is a plot of empirical data and the other was plotted mechanically using a device developed at mit. 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. Speed torque gradient.