variable frequency drive hack
variable frequency drive hack
(OP)
I'd like to use batteries to power the DC bus, and modify a small VFD to control a larger HP AC induction motor.
Is there any DIY info available about how to "marry" a small VFD to larger capacity output devices? (ie: IGBTs rated for higher voltage/amperage.)
Any help appreciated.
Regards,
rmarotta
Is there any DIY info available about how to "marry" a small VFD to larger capacity output devices? (ie: IGBTs rated for higher voltage/amperage.)
Any help appreciated.
Regards,
rmarotta





RE: variable frequency drive hack
Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: variable frequency drive hack
Bill
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"Why not the best?"
Jimmy Carter
RE: variable frequency drive hack
"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln
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RE: variable frequency drive hack
Don't spoil the F*U*N!!
Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: variable frequency drive hack
Seems like a slightly crazy thing to be doing but, like Gunnar says, it could be educational. Gotta ask though: why?
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If we learn from our mistakes I'm getting a great education!
RE: variable frequency drive hack
I know this must be an odd request because I can't seem to find much info about it. In reading service manuals from various VFD manufacturers about their models and features, it seems they all do basically the same things with the controller end. Since I have several drives in various condition that I would like to make use of, what I'm after is assembling the controls from a small drive with the components suitable for driving a larger motor.
I have some basic electronics experience, so I wouldn't be uncomfortable with fabricating some sort of interface between these components. My interest is personal understanding rather than for commercial gain. I'm not trying to re-invent the wheel.
Again, thanks for anything you gentlemen might be able to provide.
Regards
RE: variable frequency drive hack
Be careful and use the right test equipment. No crazy stunts like disconnecting the scope chassis from earth and floating it at line voltage.
Bear in mind that the DC link contains enough energy to kill you several hundred times over, and just once is enough to ruin your day.
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If we learn from our mistakes I'm getting a great education!
RE: variable frequency drive hack
* I've been out of the drive design end of things for a while now, IPMs might already be used on much larger sizes, maybe someone else can comment.
"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln
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RE: variable frequency drive hack
In a broad sense, you would have to take the IGBT's and the gate driving circuits from the large VFD's and connect the controller from a smaller one.
Ya, I like explosions.
RE: variable frequency drive hack
In my current project I want to run a 10hp 230/460v 3ph motor with an Allen Bradley 1336e series drive. The drive is rated 20hp but it's main control board is bad. It appears that all necessary signals are communicated via a ribbon cable between the main control board and the gate driver board. Anyone have info or a pin-out of these signals?
I also have a number of smaller (1-5hp) drives that are functional. The smaller drives are older AB models 1305 and 160 series. My collection has been obtained from ebay and, as you might imagine, very inexpensive. A new control board for the 20hp drive would be out of the question on my budget.
As stated ealier, I intend to run the drive from batteries. Twenty, 12v, series-connected to the DC bus.
It is my hope to later build a mains powered charger using the rectifier from the 20hp drive.
If this works out I'll try the same thing on a much larger Seimens 125hp drive.
Thanks for your interest if you have followed this far.
RE: variable frequency drive hack
7-3 has some prints
Good luck..
RE: variable frequency drive hack
"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln
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RE: variable frequency drive hack
Does anyone here know if such schematics are available?
Now I'm not an engineer, so I don't intend to try to re-design any circuits. I'm simply looking for a way to bridge between components that have already been designed for the job.
To simplify, as I understand it, the controller circuit of a drive tells it's output devices what to do in order to power the motor. When a drive is built, the limiting factor determining motor size is simply the capacity of it's output components.
Unless the driver signal values of a small drive are wildly incompatible with those of a larger drive, I can't see why an interface between the two should be difficult. After all, the principles used to control an induction motor should be the same, regardless of its size.
Thanks again for listening.
Regards,
Ralph Marotta
RE: variable frequency drive hack
I suddenly don't feel like you should do this. Sorry.
Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: variable frequency drive hack
This is something you'll have to figure out on your own. It goes well beyond the "engineering tips" nature of this forum.
RE: variable frequency drive hack
It still seems to me that conversion of existing analog & digital signals by an order of magnitude of 10 (2-20hp) cannot be that big of a deal.
Thanks to all for your trouble.
RE: variable frequency drive hack
Practically everything in todays electronics is microprocessor driven and completely proprietary property of the manufacturer. No way will they send you schematics and even if you had them what could you do wiih them? Can you repair or modify something done with SMD components so small that they have to be looked at with a magnifying glass?
Just accept what you have and do not try to modify anything.
Respect thr dangers in power equipment. One mistake and you are dead or someone else...
It seems that not much money is around for your efforts if you have to get used (junk) from Ebay..
Buy everything new with the manufacturers guarantees and let them commission the equipment. It is also possibly a tax writeoff to do so.
rasevskii
RE: variable frequency drive hack
It seems an incredibly complex method and innefficient way of powering a very old AB drive. On top of this you want to use a control card from another drive because the original one is defunct.
Quote: "... seems to me that conversion of existing analog & digital signals by an order of magnitude of 10 (2-20hp) cannot be that big of a deal"
hmm, I'm sure there might be many R&D folk and a few billion $'s thinking differently!
If it is just an experiment, then fair enough. Stand back, wear your welding goggles, make sure you have some form of protection to your batteries, don't operate it alone, carry a long dry wooden stick...
I think you get the message
RE: variable frequency drive hack
You were warned.
Mike Halloran
Pembroke Pines, FL, USA
RE: variable frequency drive hack
RE: variable frequency drive hack
"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln
For the best use of Eng-Tips, please click here -> FAQ731-376: Eng-Tips.com Forum Policies