Lincoln Series 1200, Series 1000 service manual TRANSFORMER12.6V

	oven start and cool down relay. Its normally open contacts close, supplying 220 VAC
	to the Burner Switch and enabling the 20-minute Time Delay module. The 20-minute
	Time Delay module supplies 120 VAC to the oven fan motor relay, these normally
	open contacts now close, supplying 220 VAC to the Oven Fan Motor.
TRANSFORMER(12.6V	Upon closure of the Fan Switch, 120 VAC is supplied to the primary of the 12.6 VAC
AC)	Transformer. The Transformer steps the voltage down to 12.6 VAC (normally 13 to 14
	VAC) with a center tap, and supplies power to the Time/Temp Display. The voltage
	from each leg of the Transformer©s secondary to the center tap should be one half of
	the secondary voltage.
BURNER CIRCUIT	Closing the normally open burner switch supplies 220 VAC through the oven air
	pressure switch, the gas inlet pressure switch, the normally closed high limit
	thermostat (opens at 368°C) to the ignition control. The combustion motor is now
	energized. The normally open burner blower air pressure switch closes upon sensing
	air pressure. After a pre-purge period of 30-60 seconds, the main gas valve and the
	spark generator are energized. Ignition should now occur. After proving the pilot
	flame, and a 30 second delay, the gas control relay and the burner indicator lamp are
	energized.
TEMPERATURE	Closing the Fan Switch supplies (through the Step Down Transformer) 120 VAC to
CONTROL	the Temperature Control Board. The Temperature Potentiometer is adjusted to
	desired temperature. The Thermocouple will provide varying millivolts to the
	Temperature Controller. The Temperature Controller supplies 120 VAC to the
	Solenoid Valve at intermittent intervals to maintain desired temperature. (An
	electronic flame monitor proves main flame operation in the 1033-1034 models)
CONVEYOR DRIVE	Closing the Oven Fan Switch supplies 120 VAC, through the Power Transformer, to
	the normally open Conveyor Switch. Closing the Conveyor Switch supplies 120 VAC,
	through a 3 AMP Fuse, to the primary of the Conveyor Control Transformer. The
	secondary of this Transformer supplies 10 VAC and 29 VAC to the Conveyor Control.
	The conveyor control supplies voltage pulses to the Conveyor Control. The Conveyor
	Control Potentiometer varies the frequency of these pulses. The motor speed will
	increase or decrease, as the frequency of the pulses increase or decrease
	respectively.
TIME TEMP DISPLAY	Closing the Oven Fan Switch supplies 120 VAC, through the Power Transformer, to
	the primary of the Time/Temp. Transformer. The secondary output of the
	Transformers, 12.5 to 15 VAC with a center tap, is supplies to terminals 1, 2, and of
	the Time/Temp. Display. The display works on a balanced input, and the center tap
	voltage to each leg must be 1/2 the total reading.The speed side of the Time/Temp.
	Display is supplied, by the Conveyor Control, with the frequency of the pulses to the
	Conveyor Motor. This frequency is converted by the Time/Temp. Display into a read
	out of minutes and seconds. NOTE: The Conveyor Control uses a sensor and
	magnet, mounted on the Conveyor Motor that senses when the motor is not turning. If
	the motor is not turning, the Time/Temp Display will show --:-- in the window. The
	temperature portion of the display uses a Thermistor Probe to sense oven
	temperature. The Thermistor outputs a resistance proportional to oven temperature.
	This resistance is then converted by the Display into a temperature reading.
	OR:
	The temperature portion of the display uses a "J" type thermocouple to measure oven
	temperature. The thermocouple generates D.C. millivolts proportional to oven
	temperature. This millivolt reading is then converted by the display into a temperature
	reading.

Impinger I -–1000 Series Service Manual - International 9