Lincoln Impinger Conveyor Ovens 1100 Series - Manual (Page 7)

SEQUENCE OF OPERATIONS - 1151
MODEL 1151 ELECTRIC 200 VAC 60 HZ 3 PHASE
POWER SUPPLY Electrical power to be supplied to the oven by a four conductor service.
CONTROL BOX AUTO When the temperature in the control box reaches
COOL DOWN 120°F ± 3°F (48.9°C ± 1.7°C), the Cooling Fan
Thermostat closes, switching power to the Cooling Fans. The thermostat
will open at 100°F ± 3°F(37.8°C ± 1.7°C) interrupting power to Cooling
Fans.
MAIN FAN CIRCUIT Power is permanently supplied through a 1A fuse to the primary of the
step-down transformer. The transformer steps the voltage down to 120
VAC for the control circuit. 120 VAC is supplied to terminal #1 of the 20
minute time delay relay, through the normally closed hi-limit thermostat, to
a normally open contact of the oven start relay, the cooling fan thermostat
and to the normally open main fan switch.
Closing the fan switch energizes the oven start relay. These normally open
contacts now close enabling the 20 minute timer delay. The 20 minute
time delay relay supplies 120 VAC to the coil of the oven fan relay, these
normally open contacts now close supplying 200 VAC to the main fan
motor. The cooling fans, time/temp display, conveyor switch and heat
switch are also energized.
HEATER CIRCUIT Closing the Heater Switch supplies 120 VAC through the normally open
Air Pressure Switch (which was closed by Main Fan Air Pressure), through
the 3 Amp Fuse, to the Temperature Control Board and to the Heater
Lamp.
TEMPERATURE CONTROL Closing the Heat Switch supplies 120 VAC to the Electronic Temperature
Control. The 2.5K ohm Potentiometer is adjusted to achieve the desired
temperature. The Thermocouple will provide varying millivolts to the
Temperature Control. The temperature control board then supplies 120
VAC to the coil of the Contactor at intermittent intervals to maintain the
desired temperature.
CONVEYOR DRIVE Closing the Conveyor Switch supplies 120 VAC to the DC Motor Control
Board at terminals L1 and L2. AC volts are converted to DC volts and are
supplied to the Conveyor Motor at terminals A+ and A-. Adjustment
S/N 2011383 and above of the Speed Control Potentiometer (5,000 ohm, 10 turn)
REFER TO PAGE B15 will change resistance at terminals P1, P2, and P3
varying the DC voltage to the Conveyor Motor. Thespeed of the conveyor
motor will increase or decrease as the DC voltage from the board in-
creases or decreases respectively. As the motor turns, it drives both the
reducergear box and the Tach. Generator. The tach. generatoris a DC
voltage generator which supplies a voltage to the DC Motor Control Board
and is used as a reference formaintaining a constant conveyor speed.
TIME/TEMP DISPLAY The secondary output of the Display Transformer, is supplied to terminals
1, 2, and 3 of the Time/Temp. Display. The secondary output of Trans-
former is nominally 12.5 to 15 VAC with a center tap. The voltage from
center tap to each leg is 1/2 the secondary voltage.
Impinger II - 1100 Series Service Manual - International 7