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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.