Instruction Leaflet
30-470 (E)
Page 10
Plant Exerciser (as used in Robonic Transfer Switches)
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.
The micro switch has one normally open and one normally closed
contact.
Application in Robonic Transfer Switches
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° 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 the 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 be used 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.
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2. It may be used to start an engine-generator set at selected intervals,
at least once per week, but without causing the transfer switch to
operate and transfer the load to the generator supply. At the end of
the interval it will cause the engine-generator to shut down.
Instructions To operate the engine for an interval once
each week, with or without operation of the transfer switch.
1. Extend the tabs of Dial A outwards, except those representing the time
of day for the running of the engine or operation of the transfer switch.
2. Determine the day of the week for this testing. Install the six brass
pins (called skip pins) in the spokes of Dial B representing the other
six days of the week.
3. Turn Dial A counterclockwise until the special tab at 12:00 midnight
advances Dial B. Turn Dial B until the present day of the week is
opposite the copper arrow. Turn Dial A counterclockwise until the
correct time of day (or night) is opposite the arrow on the name plate.
4. If the interval of running the engine is desired more than one day
per week but at the same time of day, remove the skip pin from the
appropriate spoke of Dial B.
Caution
DO NOT insert skip pins in any spoke when that spoke is pointing
toward the copper arrow.