Lincoln Impinger Conveyor Ovens 1100 Series User Manual

Page 10

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adjusted to desired temperature. The Thermocouple will provide varying

millivolts to the Electronic Temperature Controller. The electronic tempera-

ture controller supplies 120 VAC to the Solenoid Valve at intermittent

intervals to maintain desired temperature.

CONVEYOR DRIVE

Closing the Conveyor Switch supplies 120 VAC to the

D.C. 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 of the Speed Control

S/N 2011821 and above

Potentiometer (5,000 ohm, 10 turn) will change resistance at Refer to

Page B15

terminals P1, P2, and P3 varying the DC voltage to the Conveyor Motor.

The speed of the conveyor motor will increase or decreaseas the

DC voltage from the board increases or decreases respectively. As the

motor turns, it drives both the reducer gear box and the Tach. Generator.

The tach. generator is a DC voltage generator which supplies a voltage to

the DC Motor Control Board and is used as a reference for maintaining 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.

S/N 2011821 and above

Refer to Page B15

The speed side of the Time/Temp. Display uses a slotted disc (cemented

to tach. coupling) to break the infra-red light beam of the optical encoder

(mounted on gear motor), producing electrical pulses that are transmitted

to the display. The display converts these pulses into a read-out of

minutes and seconds.

The temperature portion of the Time/Temp 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 temperature reading.

AUTOMATIC COOL DOWN

When this oven is started, the time delay relay timing circuit is enabled,

permitting the oven fan to run for approximately 20 minutes after the oven

is shut off, to cool the oven. The Time Delay Relay will keep the coil of

Main Fan Relay closed, maintaining operation of the Main Fan Motor and

cooling fans.

CONVEYOR DRIVE

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 Motor. 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 Main Fan Switch supplies 120 VAC to the primary

(STEPPER MOTOR DRIVE)

of the Time/Temp Transformer. The secondary output of the Trans

former, 12.5 to 15 VAC with a center tap, is supplied to terminals 1, 2,

and 3 of the Time/Temp Display. The Display works on a balanced input,

and 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.

Impinger II - 1100 Series Service Manual - International

10

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