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Technical Service Manual 64 Revision Dat e: August 2004 THERE IS AN A C CIRCUIT FAILURE IN THE CONVEYOR CONTROLS There is an AC circuit f ailure in the conveyor controls , causing the conveyor to stop running. POSSIBLE C…

Technical Service Manual 63 Revision Date: August 2004

The conveyor motor has illustrated one of the following symptoms.

1) The conveyor will not run

2) The conveyor stops running

3) The conveyor speed is unstable

POSSIBLE CAUSES

Since the conveyor subsystem is an Electro-mechanical system, check the mechanical components before replacing

electrical parts. Ensure that the belt is not hung up below the oven, or that a board is not jammed somewhere on the

conveyor. After confirming that the mechanical elements of the conveyor are in operating order, start troubleshooting the

electrical components

The most likely are listed first:

1) Conveyor motor.

2) DC drive module.

3) I/O Interface board.

4) E-STOP switches.

5) Electrical enclosure interlock switches.

6) K37, K38.

7) F50, F52, F55 (When tripped, causes complete power loss to oven).

8) Controller signal).

9) Controller.).

CONVEYOR DRIVE CLUTCH NEEDS ADJUSTMENT

The conveyor drive clutch needs adjustment and this is causing one of the following symptoms.

1) The conveyor will not run

2) The conveyor stops running

3) The conveyor speed is unstable

4) The conveyor “jerks” (motion is not smooth)

POSSIBLE CAUSES

The conveyor clutch is mechanically connected to the end of the conveyor motor shaft and serves as protection for the

motor if there is a jam that actually stops the conveyor belt/chains from moving.

Exercise extreme caution when working near the conveyor drive system.

The clutch is set at the factory to slip at 35 + 5 foot pounds as measured with a linear scale. With time, the torque setting

may change. The adjustment mechanism is a large nut that presses against the clutch disc to create tension. To

increase the tension, turn the nut clockwise, the opposite will decrease tension. Use a linear scale and a hook on a chain

pin or a conveyor belt loop to pull until the conveyor stops moving. Read the measurement on the scale. The scale should

indicate 35 + 5 foot-pounds. If the tension cannot be adjusted between 30-40 foot pounds, the clutch may need to be

replaced. Other possible causes for improper clutch operation are:

1) Mechanical or lubrication problems with conveyor shafts.

2) Conveyor belt or chains catching and/or dragging

3) Conveyor sprockets slipping

Technical Service Manual 64 Revision Date: August 2004

THERE IS AN AC CIRCUIT FAILURE IN THE CONVEYOR CONTROLS

There is an AC circuit failure in the conveyor controls, causing the conveyor to stop running.

POSSIBLE CAUSES

The electrical components, which could affect the conveyor system, are mostly switches and are in the circuits that

directly affect the conveyor operation.

1) I/O relay – (A! – K12)

2) A!-K1

3) E-STOP switches (4).

4) Electrical enclosure interlock switches.

5) F50, F52 or F55 (This will cause a complete system failure).

6) A1-K3.

7) DC drive module.

All of these components can be found on the Oven Schematic.

AN ALARM CONDITION HAS OCCURRED

An alarm condition has occurred and has stopped the conveyor.

POSSIBLE CAUSES

This may or may not indicate an actual component failure. The operator must look at the computer screen to see what

alarm message is displayed and take the appropriate action from there.

The conveyor stops on a critical alarm condition. The alarms that can be set to critical are listed below.

1) One or more E-STOP switches are pressed.

2) The computer is unable to communicate with the controller.

3) The bonnet is open while the oven is operating.

4) A cell heater is not reacting correctly to the power being applied to it.

5) The safety over-temperature unit has detected the temperature of a cell

exceeding a predefined level.

6) The temperature of a cell has exceeded a predefined safety level.

7) The conveyor has stopped.

8) A circuit breaker has tripped (opened).

Technical Service Manual 65 Revision Date: August 2004

THE CONTROLLER HAS HAD A FAILURE

The controller has had a failure causing one or more of the following symptoms.

1) The conveyor stops running

2) The conveyor speed is unstable

3) The conveyor measured speed is not same as actual speed

POSSIBLE CAUSES

If the controller fails, there are other symptoms to help isolate the problem.

It is possible to isolate a controller failure by monitoring the signals from the controller at the I/O board

HINT: There is an Amber LED indicator on the front of the controller that which flashes on and off at a regular interval

while the controller is functioning properly. There also is a Green LED which is on steady when the unit is powered.

The items to check in the event of a suspected controller failure:

1) Controller.

2) Controller cables and connectors.

3) Power supply for the controller (see Oven Schematics).

PROBLEM WITH OPERATION OF TRANSFER GEAR ASSEMBLY

There is a problem with the transfer gear assembly causing either unstable conveyor speed or a

jerky motion of the conveyor.

This applies only to a combination conveyor system.

POSSIBLE CAUSES

Unstable conveyor speed and/or jerky motion of the conveyor can usually be attributed an improperly lubricated or

improperly adjusted chains or rails.

Check the following for tightness and adjustment:

1) Transfer gear assembly (sprocket and shaft).

2) Transfer gear chains.

3) Sprockets for transfer gear chains on the conveyor shafts.

THERE IS A BOARD JAMMED SOMEWHERE ON THE CONVEYOR

There is a board jammed somewhere on the conveyor and this is causing the conveyor to stop running

POSSIBLE CAUSES

There is a printed circuit board assembly somewhere in the oven that is keeping the conveyor from running. Some

places to look are:

1) The chain guards on the ends of the chains on rail and combination ovens

2) The small gap between rails and chains on combination ovens

3) Between belt and rails on combination ovens.

4) Improper boards placement onto conveyor.

If this type of problem is a regular occurrence in the oven and it happens in approximately the same place or with the

same product, then perhaps the areas in question should be realigned/readjusted. This could be a warning sign for other

problems in the mechanics of the conveyor system such as improper leveling or lack of rail parallelism.