Programming instructions

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IL 30-471 (E)
MECHANICAL COMPONENT IDENTIFICATIONGENERAL 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.” The same Standard also gives defini-
tions 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.” “Trans-
fer switch, type B means an automatic transfer 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 interrupter. The
trip settings of these special interrupters 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 interrupters, 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 Robonic’s control circuitry will auto-
matically initiate transfer to the alternate source. The trans-
fer operation will reset the “tripped” magnetic only inter-
rupter. Information on Interrupting, Closing and Withstand
ratings, for type A Robonics, are given in table 1 on page
5. Type B ‘Robonics’ are equipped with standard thermal-
magnetic breakers which will provide the required over-
load and short circuit protection. Type B Robonics can
also be built using electronic 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 Cutler-Hammer.
The Robonic provides automatic transfer of an electrical
load to a 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 mecha-
nism provides a positive mechanical interlock to prevent
both breakers being closed at the same time. The mecha-
nism 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, type B ‘Robonics’ models, type RO and
SPB type an alarm switch contact is supplied. This con-
tact 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 proce-
dure are located on the front of the operating mechanism.
All of the control modules in the Solid State Logic Control
Panel are plug-in units which are easily replaced.
Type RO
Type LRO