Instruction Leaflet
30-471 (E)
Page 4
General Description | Mechanical Component Identification |
CSA Standard C22.2 No. 178-1978 defines an automatic transfer switch as, “self acting equipment for transferring one or more load conductor connections from one power source to another.” The same Standard also gives definitions for type A and type B automatic transfer switches. “Transfer” switch type A means an automatic transfer switch that does not employ integral overcurrent devices.” “Transfer switch, type B means an automatic transfer switch that (does) employ integral overcurrent protection”. Westinghouse Robonics in type A are equipped with special instantaneous magnetic only interrupter. The trip settings of these special interrupter are set (and fixed) at higher than standard values. They are intended to trip only if the upstream protective device fails to clear a fault. Incorporating these special magnetic only interrupter, a type A Robonic operates in exactly the same way as a transfer switch not having this feature. In the event that both devices trip, the Robonics control circuitry will automatically initiate transfer to the alternate source. The transfer operation will reset the “tripped” magnetic only interrupter. Information on instantaneous trip value, interrupting, closing and withstand ratings, and recommen- dations for maximum upstream protective devices for type A Robonics, are given in tables 1, 2, 3 on page 7. The information given in these tables is necessary for proper application. Type B “Robonics” are equipped with standard thermal-magnetic breakers which will provide the required overload and short circuit protection. Type B Robonics can also be built using Seltronic or SCB breakers which could include ground fault tripping as well as overload and short circuit protection. For application information or assistance with type B Robonics, refer to Westinghouse.
The Robonic II provides automatic transfer of an electrical load to a stand-by power supply in the event of drop or loss of voltage of any or all phases of the normal power supply. Upon the restoration of the normal supply, the electrical load is automatically re-transferred to the normal power supply.
The transfer motor utilizes the power from the source to which the electrical load is being transferred. The mechanism is also designed to leave both breakers trip free in the closed position, permitting incorpo- ration of the thermal and short-circuit protection in either or both breakers. In the higher ampacity models, type RO and PRO, an alarm switch contact is supplied. This contact is connected in the transfer motor circuit to lock the motor circuit out of operation when the breaker(s) trip on an overload or short-circuit condition. Then the breaker has to be manually reset. Instructions for the reset procedure are located on the front of the operating mechanism.
All of the control modules are plug-in units which are easily replaced.
Type RO
Type LRO