Westinghouse 30-471 (E) Transformer Modules, Plant Exerciser Option# 23A, 23B, 23C, Description

Instruction Leaflet

30-471 (E)

Page 10

This time delay relay is an octual plug-in, sychronous motor type. It is complete with clutch and mechanical load switch giving one instantane- ously operated normally open contact and a timed single pole double throw contact in a dust-tight grey capsule. The mechanism is con- structed to operate for the time set on the indicating dial and then disconnect itself when the timing cycle is complete. A red pilot light on the face plate indicates that the relay is timing to operate its contacts. When de-energized, the relay requires a reset time of at least 0.5 seconds. Time delay begins immediately upon energizing the coil.

When the timing cycle is complete, a mechanical latch holds the contacts in position and the coil is de-energized.

Transformer Modules

Modules include all necessary control, voltage sensing and logic transformers.

Two versions are available. The standard module has three phase monitoring of the normal source and one phase monitoring of the emergency source. The optimal module has three phase monitoring on both the normal and emergency sources.

Plant Exerciser Option# 23A, 23B, 23C

Ratings - Input voltage 120 volts

Contact rating 20 Amps at 120 volts resistive S.P.D.T.

Description

Dial A is divided into a 24 hour day and night scale, and has tabs around the periphery which may be adjusted to operate the micro switch within intervals each 24 hours. Each tab represents a 15 minute interval. Dial B has 7 spokes and advances one position for each revolution of Dial A. Each spoke has provision to add a pin to operate the micro switch. These pins represent days of the week and their function is to prevent operation of the micro switches on selected days.

Application

The plant Exerciser is a Program Time Switch which functions to start and stop the engine-generator set and transfer switch automatically at pre-selected intervals or times. It consists of a synchronous electric motor and a gear assembly to rotate a dial 360°C each day for a week (168 hours). On the periphery of the dial there are levers or tabs which can be set to operate a mechanical load switch as dial rotates. These levers can be selected to operate the switch at specific times of the day daily or specific days of the week. The cycle repeats weekly. The Plant Exerciser may be used in two different ways as an accessory for transfer switches.

1.It may to simulate an interruption in the normal source of supply at selected intervals, at least once per week, causing the transfer switch components to function, including start-up of the engine- generator set and transfer of load to the generator supply. At the end of the interval it will initiate the transfer back to normal supply and shut down the engine-generator.