A squirrel-cage motor is the most common type of industrial AC motor. Its rotor consists of a cylinder of steel laminations with embedded aluminum or copper bars connected at both ends by conductive rings, resembling a cage. When alternating current flows through the stator, it induces a current in these shorted bars, creating an opposing magnetic field that forces the rotor to turn. They are rugged, require no brushes, and run at a speed slightly below the rotating magnetic field.
We need to swap out the old brushed DC drive for a 50 horsepower squirrel-cage motor and a variable frequency drive.
These motors draw a massive inrush current when started directly across the line, often requiring soft starters or wye-delta contactors to prevent voltage dips on the local grid.
Also heard as
- squirrel-cage induction motor
Related terms
Induction motor
An alternating current motor where the rotor current is induced by the magnetic field of the stator.
Slip
Shortfall between the speed of an induction motor's rotating field and the actual speed of its rotor.
Squirrel
Control-room shorthand for an animal-caused fault, typically a squirrel or bird bridging live parts.