Lincoln 1921, 1922 service manual Dual Technology Finisher

SEQUENCE OF OPERATION

DUAL TECHNOLOGY FINISHER

1921	208VAC	60 HZ.	3 PHASE
1922	240VAC	60 HZ.	3 PHASE
POWER SUPPLY	Electrical power to be supplied to the oven by a four conductor service for three phase.
	Black conductor is hot.
	Red conductor is hot.
	Orange conductor is hot
	Green conductor is ground.
MAIN FAN CIRCUIT	Power is permanently supplied through the 10 amp fuses, through the normally closed
	oven cavity hi-limit thermostat, to the normally open main power switch and to terminal
	number 1 of the 30 minute cool down timer. Closing the main power switch enables the
	30 minute cool down timer. The 30 minute cool down timer supplies line voltage to the
	coil of the main fan relay, its contacts now close, supplying 208/240VAC to the main fan
	motor. Voltage is also supplied to the primary of the control transformer, the conveyor
	motor, the oven control and the infrared heater switch.
	NOTE: Model 1922 ovens use a 240VAC to 208VAC step down transformer for the
	main fan motor
TEMPERATURE CONTROL	Closing the main power switch supplies 208/240VAC to the primary of the control
	transformer. Secondary voltage, 24VAC, is supplied to the oven control. The oven
	control is set to desired temperature. The thermocouple will provide varying millivolts to
	the oven control. The oven control supplies 208/240VAC to the coil of the heater relay at
	intermittent intervals to maintain the desired temperature. The display on the oven
	control will indicate when the main heater relay is energized.
	NOTE: The display also indicates oven temperature.
INFRARED HEAT	Closing the infrared heater switch supplies line voltage to the coil of the infrared heater
	relay, its contacts now close, supplying 208/240VAC to the infrared heaters.
CONVEYOR DRIVE	Closing the main power switch supplies 208/240VAC to the primary of the control
	transformer and, through the air pressure switch, the Infrared heater switch, to the
	conveyor motor. Secondary voltage, 24VAC, is supplied to the oven control. Setting the
	oven control to the desired time outputs voltage, through a reversing switch and
	capacitor, to the conveyor motor.
	NOTE: The conveyor system uses a hall effect sensor and magnet to prove operation of
	the conveyor motor. If the conveyor motor is not running, “BELT JAM” is indicated on
	the display.
AUTOMATIC COOL DOWN	When the machine is started, the time delay relay timing circuit is enabled, permitting
	the main fan to operate for approximately 30 minutes after the machine is shut off, to
	cool the machine. The 30-minute time delay relay will keep the coil of the main fan relay
	energized, maintaining operation of the main fan motor for 30 minutes.

2 DTF – 1920 Series Service Manual