| DC Motor Control Board | Check for 120 VAC input to the control board at |
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| terminals L1 and L2. If not present, check the |
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| conveyor switch and wiring back to |
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| then back to power source if necessary. If 120 VAC |
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| is present at L1 and L2, check the VDC output at |
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| terminals A+ and |
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| check the 4 amp and the 1 amp fuses on the |
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| control board. Also reset and check the mini |
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| breaker in the armature line to the gearmotor. If |
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| 120 VAC is present at terminals L1 and L2, but DC |
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| voltage is not present at A+ and |
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| amp and 4 amp fuses are good, replace the board. |
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| If DC voltage is present at A+ and |
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| does not run, check gear motor as follows. |
| Conveyor Gear Motor | If DC voltage is present at A+ and A- and the motor |
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| does not run, first check the mini breaker and then |
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| the conveyor. Refer to the next possible cause. |
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| Check the leads to the motor for evidence of any |
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| shorts or opens, and each lead to ground. If the |
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| motor fails the above tests, replace motor. Remove |
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| dust cover from the top of the motor and rotate |
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| motor shaft to determine if there is a locked rotor or |
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| a locked gearbox (use care so encoder disc is not |
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| damaged). |
| Conveyor | Check for any mechanical misalignment or |
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| improper adjustment. Also check for worn bearings. |
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| The Installation and Operations Manual shows |
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| proper conveyor belt adjustment. A conveyor belt |
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| that is over tightened will cause excessive bearing |
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| wear and sometimes, irregular speed. |
Conveyor speed | Power Supply | Check power supply at the DC control board for the |
varying or intermittent |
| 120 VAC at board terminals L1 and L2. If voltage is |
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| not present, check main circuit breakers. |
| Tach generator and DC Motor | With the power to the DC motor control board |
| Control Board | turned off, remove the leads from terminals T1 and |
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| T2.Place the test leads of a digital meter on the |
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| tach leads, turn power on, and the meter reading |
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| should be approximately 30 to 35 VDC. This |
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| reading should be steady within ± 0.2 to 0.3 VDC. If |
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| this reading is not within + 0.5 VDC, place the test |
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| meter probes on terminals A+ and |
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| reading should be approximately 150 to 160 VDC |
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| and steady within approximately 2 VDC. If the tach. |
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| voltage is unsteady, and the board output is steady, |
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| check the coupling for loose set screws or any type |
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| of damage. If the coupling checks good, the tach. is |
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| usually bad. If the board voltage output is unsteady |
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| beyond limits, then the board is probably bad. |
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| Always check the speed pot. Be sure it is okay |
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| before changing a board or tach. This test is not |
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| always 100% accurate as this test is not performed |
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| at operating speeds. However, this test is the best |
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| method currently available. Readjustment should |
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| always be attempted at least once before |
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| replacement. See procedure for board adjustment |
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| on page 65. |
| DC Gearmotor | If the DC control board is steady then the problem |
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| may be the motor or gearbox. Check the brushes in |
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| the motor for excessive arching and/or unusual |
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| wear. Check the motor and gearbox from |
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| instruction located on page 34 under "possible |
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| cause" listing "Conveyor gear motor". |
42 | Impinger I |