Impinger I -–1000 Series Service Manual - Domestic 5
Controller. The Temperature Controller switches the L2 line of the Contactor c oils at
intermittent intervals to maintain desired temperature.
CONVEYOR DRIVE
(S/N 100 to 4389) Closing the Fan Switch and the norm ally open Conveyor Switch supplies 120 VAC
through a 3A Fuse, to the Motor Control Board. AC volts are converted to D.C. volts
and are supplied to the Conveyor Motor at board terminals A1 and A2 through a
D.P.D.T. Reversing Switch. Adjustment of the Speed Control Potentiometer ( 500
ohm, 10 turn) will change resistance at terminals S1, S2, and S3 varying the D.C .
voltage to the motor. The speed of the Conveyor Motor will increase or decr ease as
the D.C. voltage from the Motor Control Board increases or decreases respect ively.
(S/N 4390 and UP) Closing the fan switch and the norm ally open conveyor switch supplies 120 VAC to
the Motor Control Board. AC volts are converted to DC volts and are supplied t o the
Conveyor Motor at terminals A+ and A-. Adjustment of the Speed Control
Potentiometer (5,000 ohm 10 turn) will change resistance at terminals P1, P 2, and
P3 varying the DC voltage to the Conveyor Motor. The speed of the conve yor motor
will increase or decrease as the DC voltage from the board increases or decr eases
respectively. As the motor turns, it drives both the reducer gearbox and the tac h.
generator. The tach. generator is a DC voltage generator which supplies a vo ltage to
the DC motor control board and is used as a reference for maintaining a consta nt
conveyor speed.
NOTE* The 1200 Series Ovens utilize 2 complete conveyor drive systems.
TIME/TEMP DISPLAY The Time/Temp Display is energized when the Fan Switch is closed, suppl ying 120
VAC to the primary of the12.6 volt Transformer. The secondary output of the
transformer, normally 13 to 14 VAC (depending on input), with a center tap is
supplied to terminals 1,2, and 3 of the Time/Temp Display. The center tap is t erminal
2. The display works on a balanced input and center tap voltage to each leg m ust be
1/2 the total reading.
The speed side of the Time/Temp. Display uses a slotted disc (cemented to t ach.
coupling) to break the infra-red light beam of the optical switch (mounted on gear
motor) producing electrical pulses that are transmitted to the display. The disp lay
converts these pulses into a read-out of minutes and seconds.
The temperature portion of the display uses a Thermistor Probe to sense oven
temperature. The thermistor outputs a resistance proportional to the oven
temperature. This resistance is then converted by the display into a temperatur e
reading.
NOTE* The 1200 Series Ovens use a Double Pole Double Throw Switch to connect t he two
Optical Encoder Assemblies to the Time/Temp. Display. By activating the s witch,
either the front or rear belt speed can be shown by the Time/Temp. Displa y.
SEQUENCE OF OPERATIONS 1040 / 1041 / 1240 / 1241
MODEL 1040 - 120/230 VAC - 60HZ - NATURAL GAS
MODEL 1041 - 120/230 VAC - 60HZ - L.P. GAS
MODEL 1240 - 120/230 VAC - 60HZ - NATURAL GAS/DUAL BELT
MODEL 1241 - 120/230 VAC - 60HZ - L.P. GAS/DUAL BELT
POWER SUPPLY Electrical Power to be supplied to the Oven by a four conductor service. Volt age
from the black conductor to the white conductor is 120 VAC.
Black conductor is Hot
Red conductor is Hot
White conductor is Dedicated Neutral
Green conductor is Ground
CONTROL BOX AUTO
COOL DOWN When the temperature in the Control Box reaches 120°F ± 3°, the Cooling Fan
Thermostat will switch power to the Control Box Cooling Fan. The Therm ostat will
interrupt power to the Cooling Fan when the Control Box temperature falls t o 100°F +
3°.
MAIN FAN CIRCUIT Electrical power is permanently supplied to the normally open contacts of the Double
Pole Main Fan Relay, the Cooling Fan Thermostat, the normally open Main F an
Switch, and the normally open Cool Down Thermostat (thermostat closes at 16 0°F
and opens at 140°F). Closing the Main Fan Switch energizes the coil of the Relay.