Your equipment’s specifications
Motors with the same HP or kW rating can cost different amounts to rewind. Speed and winding design affect the materials and work required.
- Power (HP or kW). Horsepower and kilowatts are two units for the same thing: the motor’s rated power. Give either one. They are not separate charges.
- Speed (RPM). How fast the motor is designed to turn, in revolutions per minute. It depends on how the motor is wound.
- The rest of the nameplate. Voltage, phase, frame size and other details.
Learn more: why speed matters
A motor’s rated speed is set by how its windings are arranged (the number of poles) and by the frequency of the power supply. At the same power, a slower motor has to turn with more force (torque), so it is often built larger. In one manufacturer’s range of large motors, for example, the slower 6-pole versions were usually heavier than faster versions of the same power. This is a tendency, not a rule: some slower motors use the same frame size as faster ones.
Running a motor slowly with a variable-speed drive does not change its winding. For a rewind, what counts is how the motor itself was designed, as shown on its nameplate.
So the price does not simply rise or fall with power or speed. Each quote is based on the actual equipment and the work it needs.
Sources: US Department of Energy motor sourcebook; EASA on torque and speed; ABB motor data. See thesources page.
