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M-6023 AUTOMATIC RECYCLE UNIT
THEORY OF OPERATION
General
The unit is designed to provide a low voltage source for pilot
lights and interlock circuits.
In addition, with the transmitter
wired properly,
it provides a lock- in function on overloads for
maximum indication of source of trouble.
This lock- in feature
can be reset manually at the transmitter or at a remote point.
The third function of the unit makes recycling possible when an
overload occurs and the " tune- operate"
switch is switched to
"operate" position.
An R/C circuit operating an auxiliary relay
provides three complete recycles during a 10 second interval.
NOTE:
The above number of recycles can be changed by adjusting
a potentiometer to almost any desired number within a certain
time period.
Also,
the total recycle time can be changed by
inserting another time delay relay of the desired type.
When
using a 10 second time delay and the transmitter has overloaded,
the following will occur.
If,
during the 10 second interval,
the transmitter overload has not corrected itself,
the trans-
mitter overload at fault will lock out and remain locked out
until manually reset.
If the
transmitter experiences one or
two overloads and then clears itself,
the recycle unit will
again be ready for three more complete recycles after approxi-
mately 15 seconds.
Circuit Description
The time constant which determines the
-
p ulse interval for
recycling is the 50 K 2 W. potentiometer, R1,
and the capacity
of CIA.
When the voltage on the positive terminal of ClA
equals the voltage necessary to close the relay Ki,
this occurs
causing the capacitor to discharge through R3,
100 ohm to ground.
The discharge time constant is cnosen to allow sufficient time
for the high voltage contactor to close prior to the reopening
of relay Kl.
This discharge interval must not be sufficiently long to allfw
damage to the transmitter in an overloaded condition,
The second set of contacts on relay K2,
a slave relay,
switches the heavier currents involved in closing the
high voltage contactor and also breaking the 1Y) volts D.C.
which locks in the overload relays.
Therefore, recycling of
the reset occurs just prior to the closing of the high voltage
contactor.
The time delay relay K4 is activated the instant
that K3 ener-
gizes which occurs when an overload relay locks down.
After
an elapsed time of ten seconds or three recycle periods, K4
1/27/61.
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M-6023
Automatic Recycle Unit
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