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How do I perform DC Balancing Checks on a DG1 drive?

Power the unit up and ensure that the drive is not started. With a meter on DC measure from –DC bus to U, V & W, should read somewhere between 2-50VDC. The key that to look for is one that reads either 0VDC or a very high voltage. All 3 of the phases should read relatively even but it shouldn’t be reject unless it is outside of the range stated above. If one is found outside of the range listed above, power down the drive and contact Eaton (1-877-386-2273 x2 x6 x3) with these readings. If the readings pass start the drive and do the DC checks again. With the drive running there should be an even split from + & - DC to U, V & W (this has to be done with the drive in ramp to start and not flying start). If an IGBT is not firing the measurements will likely give 0VDC or full DC bus, if either of these are seen, power down the drive and contact Eaton. If the readings are OK ramp the drive up to full speed and check AC phase to phase on the output. There should be voltage that is normally higher than the actual rating of the drive but this will depend on the meter used. All 3 phases should be even. Then measure from each phase to ground but this may vary depending on what the input power is referenced to. Most people have a wye input so the output will kind of look like a wye and it is easier to see what phase is giving the problem if there is a problem only use this as a reference. If there are problems noted here please contact Eaton (1-877-386-2273 x2 x6 x3) with the results. If all checks are good up to this point it is not a bad idea to connect a small test motor to the drive and run it. If the drive can smoothly spin a small motor it indicates there isn’t a problem with the firing of the IGBTs in the drive. If the drive passes all of the tests up to this point it either means it takes current for the drive to fail or the motor is failing. If there is another motor close by that the drive can be run on it would be a good idea to try and run it on a known good motor. If it fails on this it is most likely the drive, if it works it is most likely the motor or grounding.