Guide
How do I cross reference an induction motor?
An induction motor turns because the stator windings create a rotating magnetic field, which induces a current in the rotor, which then tries to catch up. It never quite does, and that difference is called slip. Nothing touches, nothing wears except the bearings, which is why they run for decades.
Also called: AC motor, squirrel cage motor, three phase motor, asynchronous motor, TEFC motor, electric motor, IE3 motor, premium efficiency motor, gearmotor, brake motor, XP motor, ex proof motor, inverter motor, VFD motor
How it works
Speed is set by the supply frequency and the number of poles. A four pole motor on 60 Hz runs near 1800 rpm. The same motor on 50 Hz runs near 1500. That is why frequency matters so much on an import.
What to check before you buy
- HP or kW, and the poles or rated rpm.
- Frame size. NEMA T frames and IEC metric frames are not interchangeable without an adapter base. The foot pattern, shaft height and shaft diameter all differ.
- Mounting: foot, C face, D flange.
- Enclosure: ODP, TEFC, TENV, or washdown.
- Voltage and frequency together. North America runs 460 or 575 V at 60 Hz. Much of the world builds 415 V at 50 Hz.
- Duty cycle. S1 is continuous. S3, S4 and S5 are intermittent and matter enormously on cranes, hoists and elevators.
- Service factor and insulation class.
- Efficiency class. IE2 and IE3 are measured to IEC, NEMA Premium to a different standard. They overlap but do not translate directly.
- Hazardous area rating and, critically, which body certified it.
Published free, no form. If a supplier will not answer one of these in writing, that is worth knowing before you order.
Common confusion
Send us the nameplate photo. HP, rpm, frame, voltage, enclosure and service factor are usually all on it, and that is enough for us to come back with the closest equivalent and a written note on what differs.
What we supply in this category
- MT-0001 Standard Motors
- MT-0002 Flame Proof Motors
- MT-0003 Flameproof Brake Motors
- MT-0004 High Efficiency Flame Proof Motors
- MT-0005 Energy Efficient IE2 / IE3 Motors
- MT-0006 Inverter Duty Motors
- MT-0007 Crane and Hoist Duty Motors
- MT-0008 Geared Motors
- MT-0009 Geared Brake Motors
- MT-0010 Cooling Tower Motors
- MT-0011 Low Vibration Motors
- MT-0012 Vibrator Motors
- MT-0013 Loom Motors / Textile Motors
- MT-0014 Multi Speed Motors
- MT-0015 Lift and Elevator Duty Motors
- MT-0016 S.S. Shaft Motors
- MT-0017 Torque Motors
- MT-0018 Stator and Rotor Sets
- MT-0019 Special Application Motors