Made-in-China Insulated bearings for electric machines

Electric machine:

Type - Induction motor

Speed range - 2000 to 6000 rpm

Max torque = 50 Nm

A pulley is attached to drive-end which drives the load.

Length of shaft 210 mm

Shaft diameter 25 mm

Question: Is it necessary to use insulated bearings in this case?

In general, do we use insulated bearings for ALL electric machines?

Answer: The bearings in induction motors can benefit from insulated bearings where shaft currents are high and use the bearings as a route to earth. This I am sure you are aware. Most induction motors do not suffer with this problem however, those fed with variable frequency drives VFD can and do. If you feel that your application would benefit from some form of protection, there are other solutions which have proven to be cheaper and more effective than insulated bearings and can be fitted with no requirement to remove the armature from the machine casing (and even the load). We have a very informative website and proven success in almost any application.
For shaft sizes less than 50mm they recommend only one ring need be fitted and the rings lasts the lifetime of
the motor (Non wearing).