TM 5-3610-285-14
2-3.4 Electrical system. Consists of six subcircuits. Description of each is as follows:
a. Contactor K1 Power Circuits. With power applied to the flip-top platemaker, contactor K1 (main power
contactor) will energize, provided the lower cabinet door is closed, activating proximity switch PX1. Contacts C1 and C2
of contactor K1 being closed will then apply power to the transient suppressor (TS1) which is used to suppress voltage
spikes. Power is also made available to the master circuit breaker (CB1), the vacuum pump circuits, and via contacts of
K2, the autoformer
(XT1).
b. Master Power Switch Circuits. Power is applied to the master power switch (S1) from the master circuit
breaker (CB1). Master power switch applies power to the following components:
(1) Relay K3, used to route power in the vacuum pump circuits.
(2) Fan Motors (M1 and M2), cooling fans for the 3kW power supply.
(3)
Blower Motor (BM), used to cool exposure lamp and cabinet interior.
(4) Pilot Lamp (L1), indicates main power switch is on.
(5) Exposure control circuits.
(6)
Filament Transformer (FLT1), used to supply 12 V ac to control circuit board.
c. Vacuum Pump Circuits. Power for the circuits comes from contactor K1 (main power contactor) contacts.
Power is routed through fuses F1 and F2, contacts C1 and C2 of relay K3 (vacuum pumps relay), then through the
appropriate vacuum pump switch (S3 or S4), to the vacuum pump. Relay K3 is energized when the master power switch
(S1) is on.
d. Exposure Control Circuits. The exposure control circuits are used to energize relay K2 (autoformer relay),
which energizes the autoformer. Relay K2 can be energized manually or automatically. For manual operations, power
from the master power switch (S1) is routed to the manual switch (S2). With the manual switch closed, power is routed
through two overtemperature switches (THS1 and THS2) and the glass frame proximity switch (PX2) to energize relay
K2. Overtemperature switches are set at 200°F (93.3°C) and are mounted next to the strike transformers in the power
supply circuits. They open in the event that the temperature around the strike transformers reaches 200°F (93.3°C). The
glass frame proximity switch is closed when the vacuum frame is locked in its horizontal position. For automatic
operation, relay K2 is energized in the same manner as in manual operation. Instead of power coming through switch S2
to THS2, power comes from the electronic circuits. These circuits are comprised of the following components:
(1)
Photodetector Assembly (PE1). Used to detect the intensity of the exposure lamp. It is wired into the control
circuit board. The more intense the light, the less resistance applied, which affects exposure time.
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