TRANSFORMER (12.6 | Upon closure of the Fan Switch, 120 VAC is supplied to the primary of the 12.6 VAC |
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 Fan Switch and the normally open Burner Switch supplies 120 VAC |
| through the Air Pressure Switch, to the Temperature Control Board, the normally |
| open contacts of the Burner Motor Relay (Burner Motor Relay discontinued after S/N |
| 14791) and the primary of the 24 VAC Transformer. The transformer©s secondary |
| supplies 24 VAC to the burner motor relay coil (the normally open contacts close |
| within 30 seconds), and the normally open Centrifugal Switch. When the relay |
| contacts close, the Burner Blower Motor is energized. As this motor reaches approx. |
| 1,600 R.P.M its internal centrifugal switch closes, supplying 24 VAC to the Gas |
| Control Valve. When the Gas Control Valve is supplied with 24 VAC, the pilot valve |
| is energized, and the igniter circuit is energized. Ignition should now occur. After pilot |
| flame is proven, the Main Gas Valve is energized. The Burner Indicator Light is also |
| energized. |
TEMPERATURE | Closing the Fan Switch and Burner Switch supplies 120 VAC to the Temperature |
CONTROL | Control Board. The 1K or 1000 ohm 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. |
CONVEYOR DRIVE | Closing the fan switch and the normally open conveyor Switch supplies 120 VAC to |
(S/N Q14790 & Below, | the Motor Control Board. AC volts are converted to DC volts and are supplied to the |
1200 series | Conveyor Motor, at terminals A+ and |
S/N Q14973 & Below | Potentiometer (5,000 ohm 10 turn) will change resistance at terminals P1, P2, and |
1000 series) | P3 varying the DC voltage to the Conveyor Motor. The speed of the conveyor motor |
| will increase or decrease as the DC voltage from the board increases or decreases |
(S/N Q14791 & Above, | respectively. As the motor turns, it drives both the reducer gearbox and the tach. |
1200 series refer to Pg. | generator. The tach. Generator is a DC voltage generator, which supplies a voltage |
5 & 6 S/N Q14974 & | to the DC motor control board and is used as a reference for maintaining a constant |
Above, 1000 series refer | conveyor speed. |
to Pg. 5 & 6 (STEPPER) |
|
NOTE: | The 1200 Series Ovens utilize 2 complete conveyor drive systems. |
TIME/TEMP | The Time/Temp. Display is energized when the Fan Switch is closed, supplying 120 |
DISPLAY(S/N Q14790 & | VAC to the primary of the12.6 volt Transformer. The secondary output of the |
Below, 1200 series | transformer, normally 13 to 14 VAC (depending on input), with a center tap, is |
S/N Q14973 & Below | supplied to terminals 1,2, and 3 of the Time/Temp. Display. The center tap is |
1000 series) | terminal 2. The display works on a balanced input and center tap voltage to each leg |
| must be 1/2 the total reading. |
(S/N Q14791 & Above, | The speed side of the Time/Temp. Display uses a slotted disc (cemented to tach. |
1200 series refer to Pg. | coupling) to break the infrared light beam of the optical switch (mounted on gear |
5 & 6 S/N Q14974 & | motor) producing electrical pulses that are transmitted to the display. The display |
Above, 1000 series refer | converts these pulses into a |
to Pg. 5 & 6 (STEPPER) | 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 temperature reading. |
NOTE* | The 1200 Series Ovens use a Double Pole Double Throw Switch to connect the two |
| Optical Encoder Assemblies to the Time/Temp. Display. By activating the switch, |
| either the front or rear belt speed can be shown by the Time/Temp Display . |
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. |
6 | Impinger I |
