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3) 24 VAC Transformer
The 24 VAC transformer consists of fuse 1 (F1) and fuse 2 (F2) which is the primary fusing for the
transformer. For the proper rating of these fuses refer to the specific electric diagram. The transformer
is located in the right hand electrical cabinet.
Dryer models with an optional Sprinkler System have an energizing stop relay which will disable the
dryer functions (shut the dryer down) in the event of a fire. IF THE SPRINKLER SYSTEM IS
NOT ENERGIZED (POWERED) THE DRYER WILL NOT OPERATE. The Energizing Stop
Push Button is located on the front right electrical panel. On 2-Door models this Energizing Stop
Push Button is located on the right rear side of the electrical panel (when viewed from the rear).
On dryer models manufactured for 208 volt or 240 volt electric service, the step down voltage for the
Phase 5 microprocessor controller (computer) and the Programmable Logic Controller (PLC) is supplied
from the primary side of the 24 VAC transformer. On dryers that are manufactured for 380 volts and
higher, there is an additional secondary 240 VAC on the transformer that is used to supply the voltage
required to operate the Phase 5 microprocessor controller (computer) and the Programmable Logic
Controller (PLC) through fuse 4 (F4), (and fuse 5 [F5] for low voltage applications).
4) 24 VAC Control Circuit
The secondary side of the 24 VAC transformer supplies 24 VAC to various control circuits through
fuse 3 (F3) and a 20-amp fuse or an 8-amp fuse (fuse amperage [rating] is dependent on the voltage
that the dryer was manufactured with).
The first circuit is the control voltage on/off. Control voltage ( 24 VAC) goes through the "Master
Off" (normally closed) switch and supplies voltage to the "Master On" (normally open) switch. When
the "Master On" switch is momentarily engaged, the master control relay (MCR) engages. This
closes the MCR-A contactor (which is in parallel with the "Master On" switch) which will keep the
MCR enabled. If the power is interrupted or the "Master Off" switch is pressed the MCR will
disengage. The MCR-B contactor supplies power to the rest of the 24 VAC circuits.
For dryers manufactured with Automatic Doors - the purpose of the supply air is to relieve pressure
on the automatic door pistons when an emergency
stop is engaged.
5) Safety Circuits
The following circuit branches are to verify various safeties, if ALL conditions are met ...
a) The first two (2) items are the Auxiliary Contact located on the blower (squirrel cage fan) motor
and the Tumbler (basket) Motor Overload. If either of these devices trip, it will open up the safety
circuit thereby preventing the dryer from operating.
b) Dryer Level Switches circuit branch ...
(1) On 1-way tilt models, this switch is in series with the dry enable.
(2) On 2-way tilt models ...one (1) pole of each of the two (2) level switches (LS1-A and LS2-A)
are in series with the dryer level relay and the other pole is in series with the opposite piston.
IF THE OPPOSITE SIDE IS NOT LEVEL, THE DRYER WILL NOT TILT.