Hi, everybody! I am Ryan LeBlanc from SPOC Automation. I’m here today to talk to you about overvoltage and how you might prevent it. I’ll also talk about what causes the actual overvoltage events.
So, overvoltage, when it comes to our drives, occurs when the DC bus voltage goes above 900 volts. So, a common pumping application where you might see this happen is with a beam pump. If your beam pump is out of balance—whether it’s rod-heavy or weight-heavy—and when those heavy sections fall, your motor is moving faster than the drive—than the drive is commanding—and it turns that motor into a generator, feeding voltage back into the drive. And so, when that happens, the drive actually has an overvoltage controller that tries to speed up the drive to try to burn off the extra electricity. But sometimes it gets hit with such a large amount that even the overvoltage controller becomes overwhelmed, and the drive throws the overvoltage alarm.
Another way you might see overvoltage is if you have high incoming voltage from the line, as the AC voltage gets turned into DC voltage. And if the converted value is, again, over 900 volts on the DC bus, then you will throw the overvoltage fault.
H pumps, or surface pumps in general, can also see overvoltage faults when they’re ramping. So, on the ramp down, if you don’t allow a long enough ramp down pace and the motor is still spinning faster than what the drive is commanding, again, you’re turning the motor into a generator and feeding back that voltage into the drive. And you might experience an overvoltage event.
So, keeping in mind where that’s coming from, when you see that fault, it’s an indicator that the DC bus voltage got to the fault limit.
I hope this helps. And if you have any further questions regarding overvoltage events, feel free to reach out. We have tech support and field service technicians always waiting and willing to answer any questions you might have. All right. Hope you guys have a good day.
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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.