Prior to the advent of the adjustable-speed drive (ASD), the polyphase induction motor operated as a constant-speed motor. Figure 1 shows the well-known torque and current curves versus speed for the ...

If the motor produced 350 lb-ft of torque at 2,000 rpm (an impressive amount given the minimal engine speed), this would correspond to a horsepower output (at 2,000 rpm) of 133.28hp. The formula ...

While the 533 lb-ft of torque is an impressive number, it is nowhere near as important as the fact that the torque curve exceeded 500 lb-ft from 3,100 rpm to 5,800 rpm. Even down at 2,500 rpm, the ...

2. Outlining performance, ac-induction motors generate enough torque via constant ac excitation. Nonlinear torque and speed performance accelerates when drive is a constant voltage and frequency ...

Speed, torque, and horsepower are three inter-related parameters in motor control. The speed of a motor, measured in revolutions per minute ... The AC squirrel cage induction motor is essentially a ...

Changing this ratio changes motor torque. For instance, an induction motor connected to a 460-V, 60-Hz source has a ratio of 7.67. As long as this ratio stays constant, the motor develops rated ...

Variable torque: Motors have a speed torque characteristic that varies as the square of the speed. For example, an 1,800/900-rpm motor that develops 10 hp at 1,800 rpm produces 2.5 hp at 900 rpm.

Figure 2: Current versus speed and Power versus speed curve of a traction motor. It is evident that a high current is needed to overload the motor resulting in more Ohmic (or copper losses).

When there is a request for a change in the speed of the motor, the V/Hz control method adjusts the VFD’s output voltage and frequency curve, which in turn serves as an input to the motor. This method ...