Regenerative drive supplied from a UPS

Kataeb

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We have installed a regenerative drive on a machine. (it returns power back to the main supply during deceleration).
But it turned out that this machine is supplied from a UPS.
Will this cause any problems to the drive or to the ups?
Thank you
 
I would double check your premise. Sounds like you are talking about regenerative braking. so it would be extremely unlike you have a UPS to it.
 
IF there is a UPS and it isn't one that can handle regenerative loads, Then it will likely shut the UPS down on a DC overvoltage.
 
A UPS stores energy from the LINE into the batteries, generally there is no system for moving energy from the LOAD side into the batteries or back into the line side, that is not the intended use of a UPS. You might be able to get someone to build a 4 quadrant UPS, but if you have one that was bought without asking for that feature, you probably don’t have it.
 
Better if you consult an expert in electric traction and power electronics, for example those who work with electric cars or train traction systems ... but I doubt very much that a normal UPS was able to regenerate something.
 
You might be able to get someone to build a 4 quadrant UPS, but if you have one that was bought without asking for that feature, you probably don’t have it.

I think this is ultimately the answer. It very much depends on the specifics of your UPS. It's possible there is one out there that can deal with regen power, I've never checked. But I can just about guarantee you, if you have a cheap one, you won't be happy with the results in this case, even if it normally works fine for you.
 
We need a UPS for the whole plant, because there are frequent shortage of electric power, so we rely on state or generator supply.
The UPS has a rating of 500 kva, while the drive is only 90 kw and consuming less then half. So we estimate that a low current could be fed back to the UPS. Will it work in this case?
 
We need a UPS for the whole plant, because there are frequent shortage of electric power, so we rely on state or generator supply.
The UPS has a rating of 500 kva, while the drive is only 90 kw and consuming less then half. So we estimate that a low current could be fed back to the UPS. Will it work in this case?

You can't back feed into a UPS, you need to disable the regenerative function of the drive, did you read the article i posted ?
 
What are you going to do with the power if nothing needs it?

Burn it in the backup resistors... or if they're tripped, not brake at all.

I love these systems from an energy efficiency point of view, but I'm sure that a lot of my grey hairs were caused by the hassle I had with them.
 
We need a UPS for the whole plant, because there are frequent shortage of electric power, so we rely on state or generator supply.
The UPS has a rating of 500 kva, while the drive is only 90 kw and consuming less then half. So we estimate that a low current could be fed back to the UPS. Will it work in this case?

It sounds like you are using the UPS for "ride through" until your generator comes on line. If your UPS is the "on line" type, then jraef has the best option, in my opinion. If your UPS is of the "stand by" type, then tragically's advice would be correct & jraef's idea is still a good option.

Assuming your UPS is the stand by type, for the short period of time that the UPS would be on line, while the generator starts up, simply disable the regen of your drive. Most systems that I've worked with the gen set is on line within 30 seconds so disabling the regen for that short time shouldn't pose much of a problem. If it is a problem then the addition of a dynamic brake or a chopper unit may be in order.

If it were me I would not even try to use a regenerative drive is this application. A standard VFD with dynamic braking would simplify the whole thing and eliminate the possibility of damaging a very expensive UPS unit.
 

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