Specifiers must ensure that conditions have not changed since the original installation, requiring a different choice. If the duty cycle is currently intermittent, specifiers can upgrade to continuous, not the reverse. This is usually sleeve or ball, and it should be matched so that axial and rotational loads are properly considered for the type of equipment driven. This provides protection against failure to start or overload. The specification must be matched, especially on equipment with automatic start cycles and where difficult access conditions are encountered.
Some applications require a manual restart if potential danger of sudden, automatic restarts exists.
While proper specification is essential in selecting the right motor for the application at hand, attention to installation and preventive maintenance will extend the useful life of motors. Managers and specifiers should consider these issues during specification to guarantee they can be provided once the application is in place and running. Try the circuit with a continuity tester to make sure it is de-energized. Even after the switch was de-energized, a person has been badly injured because another circuit, bypassing the switch, remained connected to the same motor. A good principle to follow is that if you didn't install it, don't assume it is to code.