GSI Outdoors PNEG-630 DC Drive Metering Roll System, Metering Roll Operation, Check the Motor

Troubleshooting Tips Portable Dryer Troubleshooting

DC Drive Metering Roll System

Symptoms: Metering Roll will not turn,

dryer shutdown-"Metering Roll Drive Failure"

Metering Roll Operation

•The DC drive system on the portable dryer is used to control the output of grain from the dryer. It is adjusted from the front of the control box using the high and low metering roll potentiometers. Compo- nents used in this circuit are the SCR contactor, SCR drive board, DC motor/ gear box, and the input/output board from the Electronic Monitoring Control System.

•All voltage for the drive system comes from terminals 1-(L1) and 3-(L2) of the SCR contactor. There should be 220 volts AC across these two points even if the unload system is turned off. If this voltage is zero, check your incoming main power.

•When the unload system is turned on you should be able to observe the SCR contactor energizing. The power to the contactor should turn on and off with the unload switch. You can check for power by putting an AC voltmeter across terminals A1 and A2. Across these points you should read 120 Volts AC. Also on the top of the contactor you can see a plunger pulling

in whenever the contactor coil gets power. When the contactor is energized, power is transferred from terminals L1 and L2 to terminals T1 and T2. Understand that L1 and L2 are the Input of the SCR contactor and T1 and T2 are the Output of the contactor.

Check the SCR Drive Board

•Next if all the above checks out okay, put

your voltmeter across terminal L1and L2 of the SCR drive board. You should get 220 Volts AC across these points when the Unload Switch Is

in the 2 Speed position. If this is present then the SCR contactor and input/output board are okay.

•If 220 volts AC is present across input of the SCR drive board (L1 and L2) then check for voltage across the output of the board. Change your voltmeter to check for DC voltage at a range above the 200 volt scale. Put the leads across A+ and A-. The voltage across these two points will vary depending on where the speed control poten- tiometer is turned. Also try turning the poten- tiometer up and down. The voltage should go from zero to approximately 180 Volts DC. If zero voltage is present across the A+ and A- terminal, first try to disconnect the wires from these two points and then check for DC volts again. If the voltage returns, suspect a bad motor or a problem in the wiring to the motor. If the voltage does not return, suspect a bad DC drive board.

Check the Motor

•The wires attached to A+ and A- go directly to the DC drive motor on the dryer. You may remove the top cover of the motor and check for the same DC voltages mentioned above at the motor. If the voltage is not present try to disconnect the wires, then check for DC volts again. If you do not get any voltage then look for a broken or loose wire between the motor and the drive board terminals.

•If the voltage is present suspect the motor or the gear box. Removing the motor from the gear box and trying to run the motor only is one way of narrowing down the problem, or you may want to remove the chain and see if the metering rolls are froze up. Using a pipe wrench is an easy way to try and rotate the metering rolls.

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