Supply vfd with dc power

I would stay away from the external DC supply when you have a manufactured solution ready to go.
if you can supply a 40hp VFD for $4500 that's good price.
then you also have to consider the warranty if you patch something together and it blows up you are stuck with the repair yourself along with other damages that may happen
 
Lots of great points posted here.

We use a lot of single phase power around this area, particularly in the rural sections, for irrigation and other large HP applications.

The Bonitron unit has proven very reliable, but limited. I don't believe you can parallel them. We have had to resort to designing larger systems, in some cases up to 350hp.

It's good to note that once you have the DC source, you can run multiple drives from it, thus giving a few other benefits and some savings.

Not having to oversize the drives is nice for the OEM who has an existing 3ph design. However, not all VFD Manufacturers allow common DC Bus connections.
 
DC chokes, DC reactors ?
I think people need to look up what an inductance is (come on gurus).
It is only a coil of wire that slows up the rise and fall of what goes in and comes out.

People need to read manuals, we used to say to customers, "RTFM" they say what does that mean?? ( "read the ****en manual).
Nearly if not all ( see GS learning) questions can be answered by reading the/all manuals--- but who has the time when gurus give there time away for nothing.

Apart of course people that are making money from this site , sorry Ron and Dabba, but yo are between you, the more knowledge about AB ( as money sucking as they are if you pay for it, AB not you guys)
So if people just learn't buy reading , or learnt by learning from instead of being in a position where they should not be, this website and l wouldn't be here.
Are the paradox.

I also learnt all/maybe some of what jraef (when as VSD teh rep) says about VSD, it's not hard when you want to understand how things work.

BUT isn't easier to just get the answer and of course it is right because it's on the internet, even from gurus. (which l do respect)
KD
 
What difference then does a DC reactor make when sizing a drive for single phase input? I've been told by some drive manufactures that DC reactors are mandatory even with 3ph input.
 
A DC reactor (choke) reduces AC input line current harmonic distortion while absorbing DC bus voltage spikes.
 
I am looking into this discussion a bit more. I have a customer that wants to run a 100hp motor when all he has available is 1ph 230V. He cannot get the power company to give him a 460V service. And 3ph service is too far away and very expensive to pull in.

What would ya'll advise would be the best way to approach this? Should use a 100hp 230V drive paired with a Bonitron or such like so it can handle the single phase power? I guess another option would be to install a step-up transformer and do 480V equipment. I would probably just use a 200hp 230V drive except that they are rare and expensive.

Any one been through a case like this? Any words of wisdom on the best way to take?
 
I have lived in Pa all my life and I know that you can get 3Ph power to any part of the state. Granted you may have to pay to have the lines run.
at 100HP I would first have a talk with the power company engineer it may be cheaper to pay them to run the lines.
if you don't need the features of a VFD you may be able to get it to work by adding some caps between T2 and T3 on the motor. Did that on a 40 HP motor years ago worked fine
the only other way is either a 200HP high quality VFD or contact you motor vender for 100HP single phase motor if you don't need variable speed
 
To get PPL to run 3ph 0.8mile, we could buy a couple bonitrons and bunch of drives
 
I havent heard of adding caps between T2 and T3 before. Can you offer a few more details and explaint that bit?
 
As I said I have done it before the trick is selecting the caps
I used motor starter caps
I just added them in until I got it to work I don't remember what we ended up with
I worked for that company for about a year after that and no call backs
I can tell you this it is not recommended by anybody not even me but it will work
if you try it you are on your own.
 
you could put in an MG set or a rotophase they are both popular in your area PPL is the same power co that I deal with you must be close.
keep in mind that 100 HP on single phase line may give you other problems
and PPL will disconnect you if something you do causes problems on there system
voltage drop on start up is one reason for disconnect power factor correct is another reason so you still want to run this by their engineers no point in getting in beef with them
 
Before you waste ANY more time on this idea, you have to understand one core basic concept about what you are thinking of doing here.

100HP at 230V single phase is going to require over 420A of 230V single phase current! You cannot get around that fact, and in fact because of losses in the VFD and transformer to go from 230-460V, you will actually more likely start approaching 500A of 230V 1 phase current. Unless your customer has some sort of extremely unusual service from the utility, I seriously doubt he has anything larger than a 400A service, which in reality is actually going to be limited to 320A (because that's the limit on meters).

3 phase is probably his best option here, but he also will need to understand that in most cases, along with a 3 phase service comes a nasty little surprise he may not be aware of, called a "Demand Meter". If he ever exceeds his Peak Demand limit, the utility penalizes him with a multiplier on his basic rate, sometimes as much as 3x! It's a "gotcha" that a lot of people are unaware of.
 
I am looking into this discussion a bit more. I have a customer that wants to run a 100hp motor when all he has available is 1ph 230V. He cannot get the power company to give him a 460V service. And 3ph service is too far away and very expensive to pull in.

What would ya'll advise would be the best way to approach this? Should use a 100hp 230V drive paired with a Bonitron or such like so it can handle the single phase power? I guess another option would be to install a step-up transformer and do 480V equipment. I would probably just use a 200hp 230V drive except that they are rare and expensive.

Any one been through a case like this? Any words of wisdom on the best way to take?

Here in the big 'Cornfield with a Racetrack in the middle', we have center pivot irrigation all over the place. At a cost of $20-50k per mile, 3 phase power is not cost effective.

We have done several 100hp+ and a bunch of 50-75hp power supplies for these pump applications. The systems are well-proven. On one such as this, I would suggest a transformer, 230-460 1ph, feeding the cabinet. For that matter, if the utility prefers, you could go 4160-460, and they might supply the transformer.

The Integrator who builds these is: http://www.mesindy.com/
 

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