Lincoln Series 1200 Manuel D’Utilisation

Impinger I -–1000 Series Service Manual - International

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

AC)

Upon closure of the Fan Switch, 120 VAC is supplied to the primary of the 12.6 VAC

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

CONTROL

Closing the Fan Switch supplies (through the Step Down Transformer) 120 VAC to

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.