What is explosion proof electric motor?

Question

What is explosion proof electric motor?

Answer 1

An explosion proof motor is approved for use in an area that has an explosion hazard due to combustible gas, vapor or dust. That means that the exterior surface temperature must not exceed limits set for the type of atmosphere for which it is approved. If gas, vapor or dust enters the motor and is ignited, the flame must be confined to the interior of the motor so that nothing is ignited in the exterior area. That requires that all joints in the housing of the motor and the conduit access must be sufficiently strong and tight and must have sufficient surface area contact in the joint. The motor may require temperature monitoring devices such as thermocouples, thermostats or resistive temperature detectors that will de-energize the motor if the interior temperature exceeds a certain limit. Depending on jurisdiction, the motor may require testing, approval and labelling by an independent testing organization. Approval labels would include temperature limits and/or codes indicating in what type of atmosphere the motor may be used.

Answer 2

It is built in such a way that no spark can come out of it in an explosive atmosphere like Hydogen, or in a enclosed environment.