Hello, my name is Steve Scott. I’m with the SPOC Automation Aftermarket Group. I help assist our customers with technical support questions about our SPOC systems. I’ve been asked to provide some insight into three of the most common fault conditions that we typically get technical calls on. Please be aware that these units can contain high voltage, so always practice safe operating procedures when diagnosing these issues in the electrical panels.
One of the more frequent calls we get is a Code-51 external fault. This is a digital input, which is typically from the Field Kill relay. In this instance, an external device has been installed into this circuit. The device is not functioning in its normal state. This could be a vibration switch, pressure switch or some other type of safety device preventing the circuit from being completed. If all external devices checked out correctly or in their normal state, check to confirm the control voltage is correct.
Another fault we commonly get is Code-1 over-current fault. This occurs when the output current to the motor exceeds the current rating of the drive. The first thing we want to do is disconnect the motor leads from the drive and, if possible, run the drive up to 60 hertz. Then check the output voltage phase-to-phase on the drive itself across all three lines on the output. If this checks correctly, look for a possible bare spot going to the motor in the conduit. Check for incorrect wiring or an exposed wire in the motor junction box. Also, check to see if the pump is locked up or just unable to turn freely. It’s possible that the motor might have an issue with a shorted or grounded motor windings and the motor would need to be replaced.
A third instance would be a Code-2 over-voltage trip. This is when the DC bus voltage exceeds the trip-voltage for our typical input voltage. This may vary based on your drive type. One reason for this could be the input line voltage being too high, which also would cause the DC voltage to follow and also be too high.
The most common cause is regeneration on the motor, on a beam pump unit it might be out of balance or possibly just running too fast. When the pumping unit over-speeds, the drive attempts to speed up to allow the excess voltage to bleed off. If the drive cannot speed up fast enough, the DC voltage goes too high and creates this fault. One common solution for an over-voltage trip is to make sure the maximum frequency is set to 100 hertz. This will allow the drive to speed up enough to prevent this fault in most cases.
This is just a quick summary of the typical faults that you may run into and just a couple of tips to possibly get you running again. If you try some of these things that we have suggested in this video and it has not resolved your problem, please have the serial number ready if at all possible and give us a call at 844-766-2833. Our technicians are available 24-hours, 7-days-a-week for your service needs and as always, pump long and prosper.
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A variable frequency drive should only be worked on by QEP certified professionals and only following all corporate, local, state and national regulations.