CounterTop – 1300 Series Service Manual
4
MAIN FAN CIRCUIT
Electrical power is permanently supplied through the Control Box Hi-Limit to terminal one (1) of the 20-
Minute Timer. When the DPST Fan Switch is closed, the timer is enabled. This energizes terminal two
(2) of timer, which supplies power to the Coil of the Fan Relay and the Cooling Fan Motor. The normally
open contacts of the Fan Relay now close energizing the Main Fan Motor. Closing the Main Fan Switch
also supplies power to the Conveyor, Control Transformer, and the Electronic Temperature Control
Board.
TEMPERATURE CONTROL CIRCUIT
Closing the Main Fan Switch supplies power to the Temperature Control Board. The Temperature
Control Potentiometer is adjusted to the desired temperature. Power is then supplied through the
normally closed High Limit Thermostat and the Main Fan Air Switch to the Coil of heating element relay.
When the contacts of the heating element relay are closed, power is then applied to the 5600W Heating
Element. The Thermocouple provides varying millivolts to the Temperature Control Board. The
temperature control board supplies voltage to the Coil of the heating element relay at intermittent
intervals to maintain desired temperature.
CONVEYOR DRIVE
Closing the Main Fan Switch supplies voltage to the primary of the Transformer, the secondary of the
Transformer then supplies 24 VAC to the Conveyor Control Board. AC voltage is converted to DC
voltage and is supplied to the Drive Motor at terminals J3(-) and J2(+). Adjustment of the Speed Control
Potentiometer will change resistance at terminals P1, P2, and P3 varying the DC voltage to the motor.
The speed of the conveyor motor will increase or decrease as the DC voltage from the board increases
or decreases respectively.
NOTE: The conveyor control uses a sensor and magnet mounted on the conveyor motor that senses
the motor speed. Any change in motor load (± RPM) is detected by the sensor and the voltage to the
motor is adjusted accordingly.
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