VFD and MCC question

Lots of manufactures make small VFD's as retro fits to most manufactures buckets. If you have a bucket with a size 00 and a CPT (control power transformer) your probably in trouble. The CPT is almost as big as the starter.

Find beg or borrow an YES book from Cutler-Hammer-Eaton Electrical. The book is amazing for older Westinghouse and CH products. EE also has a book on retro fits In the GE and SQ Dog lines.

I would be careful, modifying new equipment, it can lead to voiding any warranties left. Do you really need a VFD? Would a soft start work? EE makes some pretty small soft starts, I have installed them into existing buckets lots of times. Personally most people use a VFD for the soft start. Not because the load is variable. I worked at a place where we had over 700 VFD's. Less than

30 were really a variable load. Most started ramped up to 100 percent and stayed there. What a waste of dollars.

I would suggest that you look at the type of MCC you have and open up the wiring doors, do you have any spare space top or bottom? You might and not know it. Then you can re-arrange the buckets and remove the old size 00 bucket and possibly get a size 1 bucket in place. Check used equipment dealers for the buckets. Hang on to your shorts they aint cheap.

I once was revamping a Westinghouse MCC for a pumping station. It was cheaper to order an complete new MCC than it was to buy the new buckets and starters. So each night I would remove one old and replace it with one new. Then do the next one. I ended up with old grey sheet metal with new buckets and new sheet metal and old buckets. We sent the old stuff to salvage. We kept 2 buckets of each size.

In closing stick to the majors for VFD's personally I like ABB, EE, and SQD. I have not worked on any of the current generation Toshibas and other manufactures so your going to have to listen to the rest for them.

Sure, no problem,...except for a few details.

Define the HP (or kW) size of your VFD Define the maximum hieght of the bucket you wish to fit it in Define the MCC depth in front of the bus bars Define the rating of the enclosure you can live with Define how you plan on keeping it cool Define how you plan to get power to it, i.e. circuit breaker or fuses Define if you need line and load reactors Etc. etc. etc.

Retrofitt>Does anybody if there is a manufacturer that makes a VFD that would fit into

Erik, most VFDs are designed to go *outside* the MCC - on the wall somewhere - for air circulation cooling reasons. It gets very hot inside some MCCs..

I'm not saying you can't get something, somewhere, though..

Cameron:-)

I think this would be difficult if not impossible. The heat generated by VFD's requires special cooling fins and fans for the same size motor that can be operated from a bucket. VFD's operate at a relative high temperature.

All the vfd's I have seen in mcc buckets had two small fans with filters in the door.