Lock Motor And Latch Circuit - LG LRG30855S Series Training Manual

LOCK MOTOR and LATCH SWITCH CIRCUIT
The lock motor circuit and the door latch switch circuit control the locking and
unlocking of the door.
The lock motor is energized when the SELF CLEAN cycle is initiated with the
door closed. The lock motor circuit applies voltage (120 V
This circuit is from the motor door lock relay (MDL location on ERC), to the
lock motor, through the door switch to neutral.
For this circuit to be complete, the lock motor circuit must be energized by the
ERC and the door must be closed. An open oven door results in LOCKED
flashing in the display and alarm sounding after the control has been
programmed for clean and START has been selected.
The door latch switch circuit signals the control if the lock motor is in the
unlocked or locked position or somewhere in between (transition). There are two
latch switches operated by the cam located below the lock motor.
The door latch switch circuit is from the ERC, through one of the latch switches
(switch 1 for unlocked or switch 2 for locked) back to the ERC. If neither switch is
closed, and the oven temperature is below 450°F (232°C) the ERC will energize
the lock motor circuit until the correct switch closes to complete the circuit. (If
circuit to the correct switch is open, the lock motor will run continuously with the
oven below 450°F (232°C).
The cam on the motor performs two functions:
• Positions the lock hook in the door to prevent opening during the
CLEAN operation.
• Operates the latch switches which tell the control if the door is unlocked
or locked and ready for CLEAN operation.
Note! When the door is either being locked or unlocked, both latch
switches will be in the open position.
The movement of the cam has also closed lock switch 2 which signals the control
that the door is locked. The control then removes power from the lock motor
circuit by de-energizing the lock relay. The lock motor stops and lock switch 2 is
held closed by the cam through the clean cycle. The word LOCKED stops
flashing and remains illuminated in the display. The word ON remains illuminated
in the display. During the Clean Cycle, the oven will cycle to maintain an average
clean temperature of 815° F (435° C).
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) to the lock motor.
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