Section C - Electrical Circuits; The Compressor/Evaporator Fan Motor Circuit - Electrolux FROST- FREE Service Manual

SECTION C - ELECTRICAL CIRCUITS

There are (5) electrical circuits in the frost-free freezer:
1. The Compressor/Evaporator Fan Motor
Circuit.
This circuit is made up of the cold control, contacts
1 and 2 of the defrost timer, compressor, and
evaporator fan motor.
When power is applied to the freezer, line 1 is
connected to the cold control. The cold control is an
hydraulically operated switch that senses the
temperature in the freezer. When the temperature in
the freezer raises above the cold control setting the
contacts close applying power to terminal (1) of the
defrost timer.
The defrost timer is a single pole double throw switch
that is operated by a motorized cam. The cam
turns one revolution every (12) hours that power is
supplied to the motor. The contacts between
terminals (1) and (4), of the defrost timer, are closed
for 11 hours and 30 minutes of the 12 hour cycle
providing power to the compressor and evaporator
fan motor circuits.
The compressor motor and the evaporator fan motor
are connected electrically in parallel. Power from
terminal (4) of the defrost timer is applied to the over
load protector of the compressor. The overload
L1
DEFROST
TIMER
1 4
COLD
CONTROL
C
OVERLOAD
COMP. MOTOR
protector is a thermal device that senses a
temperature of the compressor shell and prevents
damage to compressor motor by removing power if
the compressor overheats.
The overload protector is connected to pin the "C" of
the compressor. Pin "C" of the compressor is
connected internally in the compressor to the end of
the start and run windings of the compressor motor.
The other end of the run winding is internally
connected to pin "M" of the compressor, while the
other end of the start winding is internally connected
to pin "S" of the compressor.
The compressor start relay is pushed on over
compressor pins "M" and "S". The start relay is
a current sensitive relay, made up of a coil and a set
of contacts. The coil of the relay is connected
between pin "M" of the compressor and terminal (2)
of the relay, which in turn is connected to neutral.
The contacts of the relay are connected between
terminal "S" of the compressor and terminal (2) of
the relay.
The evaporator fan motor is connected between the
defrost timer terminal (4) and neutral. This puts
evaporator fan motor electrically in parallel with the
overload protector, compressor and start relay.
Electrical Current Flow
When the contacts of the cold control close, powers
is applied to terminal one of the defrost timer. If the
S
START
M
RUN
EVAP. FAN
MOTOR
19
RUN CAPACITOR
IF APPLICABLE
S
M
COIL
START
RELAY
N
2