Any Motion Control Engineers/Experts Here?

I have a variable frequency controller that controls the speed (RPM) of a 10hp electric motor. The motor drives an A/C compressor that I use in my calorimeter. The controller is part of a system that was designed and built by an outside company that is now out of business. Its a Nextdrive SC4410-01000, and recently stopped working and shows an output short. I've eliminated all outside potential sources of the fault, so I'm now fairly confident that the controller is bad. Its also out of production. So I need to replace it with something as similar as possible to ease the integration of it into the system. Problem is I know how to use it, but don't know much about these types of controllers in general. So can anyone educate me? Here's a link to the manual and specs for the controller I currently have.

http://webcache.googleusercontent.com/search?q=cache:fsYKTzB04Y4J:www.kollmorgen.com/en-us/products/drives/discontinued/sc4000/sc4000-manual/+&cd=1&hl=en&ct=clnk&gl=us

I would think any old electrical contractor that does commercial work could install a new VFD with the same capabilities.

In reply to RossD:

Well yes, but that wouldn't be the GR way of doing it, would it?

Since it seems pretty obvious that he is playing with some high dollar stuff, calling in a pro would be a better idea. There are times that grassroots engineering is not the best choice.

i thought you were going to be looking for someone from Motion Control Suspension and was going to have some contact info for you

In reply to cwh:

Well I am an engineer myself, so I think I can handle it if someone can educate me about this type of AC drive control. Calling in someone else usually takes more time than figuring it out myself.

I'm not familiar with Kollmorgen variable frequency drives in particular, but I deal with VFDs every day. If you want to stay with the same brand, Kollmorgen still sells them: http://www.kollmorgen.com/en-us/products/drives/servo/servo-drives/ (although it appears they are probably just slapping their nameplate on another brand they buy in); you could call them and ask what they recommend to replace your existing drive.

Otherwise there are any number of manufacturers out there that make similar products. Popular name brands include Allen-Bradley, ABB, and Yaskawa.

In reply to stuart in mn:

The one I have is actually a Warner Electric SC4410. Apparently the product line was purchased at some point by Danaher, and was renamed Seco. Then it changed again to Kollmorgen. In any case, its no longer available, but maybe you can help me. Other than horsepower and electrical requirements, what other factors should I be concerned about when selecting a VFD?

HP and voltage are the main things.

I assume there's some sort of closed loop control of the drive? In other words, the speed is automatically controlled based on an input signal? Or, is it manually set to operate at some fixed speed? If there is a control loop, you'll probably have to play with the control settings to get a new drive to operate the way you want it to.

The control signals for start, stop, speed setpoint, speed feedback, or drive failure can be done either via discrete input and output connections to the drive, or over a communications bus (i.e. Ethernet, etc.) I'm guessing your setup has discrete connections; if that is the case it should mainly be a matter of reconnecting the appropriate wires to the replacement drive.

The brand names I mentioned earlier are just a few of the manufacturers, there are probably dozens more. It's probably best to use one that is available locally, that will make it easier for support (when getting it started up) as well as for service later down the road.

I'd suggest checking your local Yellow Pages for systems integrators, those kinds of companies typically can provide a VFD along with setup and installation as needed.

I would think the GRM thing to do is find a used one on dovebid or labx.