The MS-2 test set, from Macey's Electrical , is used by several thousand utility companies, industrial plants and electrical service organisations.
Using the new technology, Model MS-2 is a self-contained test set that incorporates a variable high-current output and appropriate control circuitry and instrumentation for testing thermal, magnetic or solid-state motor overload relays; moulded-case circuit breakers and ground-fault trip devices.
Model MS-2 is capable of testing the time-delay characteristics of motor overload relays and moulded-case circuit breakers rated up to 125 amperes, when following the recommended test procedure of testing the time delay of these devices at three times their rating.
Higher currents are available for the short durations required to test an instantaneous trip element.
For example, the test set will provide a maximum short duration output of 750 amperes through a typical, 125 ampere, moulded-case circuit breaker.
Additional applications include verifying the ratio of current transformers and testing panel-board ammeters and voltmeters.