Drive Motor Circuit; Temperature Sensing Circuit; The Heating Circuit - GE DSXH47EG Technical Service Manual

Drive Motor Circuit:

When power is connected to the dryer, line 1 is applied
through the thermal limiter (a non-resettable fuse
mounted on the rear wall of the dryer) to the COM terminal
of the door switch.
When the door is closed the COM terminal is connected
to terminal NO of the door switch. From terminal NO
power is applied to terminal J4-2 of the motor relay RL
1 on the control board. When the control board closes
relay RL 1 power is applied through terminal J4-1 to
terminal M4 of the drive motor.
Terminal M4 is connected inside the motor to one side
of the thermal overload. (The thermal overload protects
the motor from being damaged by overheating.) The
other side of the thermal overload is connected to one
end of both the run winding and the start winding of the
drive motor. When the motor is not turning, the other
end of the start winding is connected internally to
terminal M5 of the motor through the NC contact of the
motor centrifugal switch. The other end of the run
winding is also connected internally to terminal M5,
which is connected to neutral.
When the motor is not turning, the start winding and
the run winding are connected in parallel. When the
contacts of relay RL 1 are closed, with the dryer door
closed, line 1 and neutral voltage is applied across both
the start and run windings of the drive motor. With power
applied to both the start and run windings, the motor
starts to turn.
When the speed of the motor reaches about 80% of
it's normal run speed, the contacts of the centrifugal
switch remove power from the start winding thus removing
the start winding from the circuit.
The drive motor preforms two tasks in the dryer. A pulley
attached to one end of the motor shaft uses a belt to
drive the dryer drum. The blower wheel is attached to the
other end of the motor shaft to pull the air through the
clothes and force it out the exhaust vent.

Temperature Sensing Circuit:

The temperature in the dryer is controlled by the control
thermistor and the electronic control board. The control
thermistor, mounted in the blower fan housing, is a
negative coefficient thermistor that decreases in
resistance as the temperature increases.
The electronic control board reads the resistance of
the thermistor and converts it to temperature. It compares
the reading from the thermistor to the temperature setting
for the cycle.

The Heating Circuit:

The electronic control board applies power to the
heating circuit through the contacts of heater relay RL
2. When the electronic control senses the temperature
in the drum is below the programmed temperature, it
closes the contact of RL 2. This applies line 1 power to
the high limit thermostat mounted on the heating
element assembly.
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