Over voltage fault

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ptonsparky

ptonsparky

Tom
Location
NE (9.06 miles @5.9 Degrees from Winged Horses)
Occupation
EC - retired
Bought some software to set the parameters on AD vfds. Cheap, I know, but they arrive in two days, I can order anytime. Support otherwise..well maybe.

I have a small one on my home water pump and just happened to look at the last faults recorded. All overvoltage. In my limited experience that means to short of ramp time on deceleration. Normally I use coast to stop for wells but it was causing the pipes to jump around so I had put in .5 sec for decel time. Default for the drive is to ignore ov warning. Would this continued ov cause me grief in the future?
 
hurk27 said:
can you think of any motor that can decelerate in a half of a second?, may be putting on the breaks to hard for such a small unit.
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I'm thinking a little along that same line but don't think decelerating the pump in half a second is unrealistic. When set to coast to a stop it very well could be stopping that fast or faster.

If he has hammering pipes when coasting and not when decelerating in half second it is likely stopping faster when coasting.

What may be needed is to let it coast to stop but install expansion tank or make sure expansion tank has sufficient air in it to absorb sudden pressure changes
 
ptonsparky said:
Oh, I agree. Took that off for now at least. Was wondering side affects of continued ov faults if ignored.
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Depends on what causes them. If it's the rapid decel as you think, then probably no harm. If it's coming from line surges, depends on the peak of the surges. Still, probably no real harm unless it also involves serious spikes that may overwhelm the TVSS in the drive front end. If the OV fault go away when you disable the short stop, I wouldn't worry about it.

But if you were getting noise like water hammer from the coasting stop, is it safe to assume this well has a foot valve? If not, i.e. self priming, then letting the water fall back into the well is causing the motor to spin backwards and ANY decel setting is going to give you OV faults. If there is a foot valve and it's slamming, then you want a LONGER decel to allow the kinetic energy in the water colum to dissipate more slowly so the valve closes gently.
 
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