Westinghouse Switch warranty Type RO

General Description

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.”

“Transfer” switch type A means an automatic transfer switch that

does not employ integral overcurrent devices”. ‘Transfer switch, type B

Type LRO

means an automatic switch that (does) employ integral overcurrent

protection”. Westinghouse Robonic automatic transfer switches are

available in both types. Robonics in type A are equipped with special

instantaneous magnetic only breakers. The trip settings of these

special breakers are set (and fixed) at higher than standard values so

that they will trip only if the upstream circuit protective device trips.

Incorporating these special magnetic only breakers, 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 upstream protective

device and the magnetic only breaker in the Robonic) the Robonics

control circuitry will automatically initiate transfer to the alternate

source. The transfer operation will reset the “tripped” magnetic only

breaker.

Information on interrupting, closing and withstand ratings, and

recommendations for maximum upstream protective devices for type

A Robonics, are given in tables 1, 2 and 3, on page 7.

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. For application information or assistance with type B

Robonics, refer to Westinghouse.

The Robonic provides automatic transfer of an electrical load to a

Type RO

standby 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 retransferred to the

normal power supply.

The transfer motor utilizes the power from the source to which the

electrical load is being transferred. The mechanism provides a positive

mechanical interlock to prevent both breakers being closed at the

same time. The mechanism is also designed to leave both breakers trip

free in the closed position, permitting incorporation of 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.

Most of the control components are plug-in units which are easily

replaced.

5. Control Panel

Type PRO