Jenn-Air JB36NXFXLW00, Technical Education

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3-3
COMPRESSOR
The main control board supplies a 5 vdc, peak-
to-peak square wave, at 54 to 150 Hz, to the
inverter board. A standard VOM will read ap-
proximately 2.5 vdc. The inverter board sup-
plies the variable capacity compressor with
three-phase 230 vac. Varying the voltage and
frequency to the inverter board changes the
speed of the compressor. The compressor can
run at speeds of 1620 to 4500 rpm.
NOTE: It is not necessary, nor is it recommend-
ed, to test the output of the inverter board.
While the compressor is running, its speed is
continuously updated. Speed is determined
after analyzing two factors:
The difference between the actual tempera- •
ture and the selected temperature settings.
The rate of temperature change.
•
Minimum compressor speed is based on the
freezer’s selected temperature setting, as
shown in the following chart.
The compressor generally cycles on and off
according to the cut-in and cut-out tempera-
tures of the freezer, however, the refrigerator
can turn on the compressor if the evaporator
fan is at maximum speed and the refrigerator
temperatures are not dropping.
COMPRESSOR PROTECTION
To protect the compressor and maintain ef-
ficiency, minimum compressor off time is pro -
grammed into the main control board. When the
compressor turns off, a minimum of 7 minutes
must elapse before allowing a restart.
At the end of the 7-minute period, the condenser
fan motor starts, and the main control board
sends the compressor speed signal to the
inverter. The inverter utilizes a current-limiting
device and thermal protection that eliminates
the need for a compressor-mounted thermal
protector.
EVAPORATOR FAN MOTOR
The evaporator fan motor is a 12 vdc, variable
speed motor. The motor has four wires:
A blue wire that is not used. •
A red wire provides a constant 12 vdc. •
A yellow wire provides a variable voltage •
of between 5 vdc and 17 vdc to control the
motor speed from 2000 to 3000 rpm.
A white wire provides a common return.
•
EVAPORATOR FAN & AIR DOOR DELAY
After defrost, an evaporator fan delay avoids
unnecessary movement of warm, moist air
through the refrigerator by chilling the evapora-
tor prior to starting the fan. Immediately after
defrost drip time, the compressor starts at
4500 rpm, but the evaporator fan is delayed
for 2 minutes.
Freezer Temperature Compressor
Setting (
°
F)
Minimum Speed
6 to –2 1620 rpm
–3 1800 rpm
–4 2000 rpm
–5 2200 rpm