Rpc to power several motors plus VFD

I've enjoyed absorbing as much info as possible in the past few weeks and learning more about motor controls and rotary phase converters has been fascinating, but I wanted to get a sanity check from people smarter than me on these topic before throwing more money at this project.

What I have:

1. Monarch 10EE with inverter duty 5 hp motor driven by 220 3Ph input 5 hp TB Wood's E-Trac AC Inverter

2. Cincinnati Toolmaster 3 hp 3Ph motor

3. 20" bandsaw 1 hp 3Ph motor

What I did not want to do:
-Put new VFD's on all 3 machines and run off 110V.

My goal:
-Make or buy a RPC that will supply 3Ph for all machines, including the clean power required to feed the existing VFD on the lathe.

I have a 10 hp 3Ph motor for the RPC. I've scoured over the different designs and feel confident I could copy the Fitch plans to make a RPC that would not burn the house down.

My questions:

1. Make or buy?

a. American Rotarty 5 hp panel only is about $280. Has everything but the motor. Looking at Fitch components on Grainger, cost for components without assembly would be 2x to 3x this. I realize many guys have scrounged the parts for next to nothing. I've spent the winter re-habbing this mill and want to spend time cutting chips more than I want to scour Ebay for every component.

b. The off-the-shelf AR panel would be fine for the mill and saw, but may not be balanced tightly enough for the lathe VFD. It seems I could tie in some more run caps to balance tighter to my motor, if I need to. Are there any issues with this- besides blowing away any AR warranty?

c. In general, what benefit is there to me building my own, besides the value of the learning experience? From what I see, it's going to cost me significantly more to build it myself, unless I spend quite a bit of time scrounging for parts, and then I have the hours of working my way through assembly.

2. If I buy the AR panel, would you recommend testing the balance first or just try to power the VFD and "see what happens".

3. If I do need to change run capacitance, should I balance it for the 5 hp lathe motor? I've seen some guys balance the voltages based on a motor in the middle of the range of motors to be powered with the RPC.

I feel fortunate to have access to this knowledge base. I'd appreciate any comments/recommendations. Another fallback option is to get the AR panel, use it to power everything without a VFD and if it isn't balanced well enough for the VFD start saving for a 10 hp VFD to debate and use for the lathe.

You are over thinking this.

Make the RPC per the Fitch guidelines. don't worry about
balance. It can never be right for all conditions.

m2salmon said:

What I did not want to do:
-Put new VFD's on all 3 machines and run off 110V.

Click to expand...

You're going to be better off if you use utility 220-230V instead of 110V.

More options..

No need to derate a single phase input rated 5 hp 220v VFD.. DOZENS of them out there.

Dump the 3 phase only input VFD on Ebay. Or derate it (if it allows single phase input) and use for Toolmaster. TB Wood’s divested its electronics product line to Vacon on December 31, 2007

A 110 volt input VFD, is only available up to 1.5 hp.

220 volt single phase VFD's available to 50 hp, but should only be used to run 1 motor.

The 10EE is the only machine that NEEDS a VFD for now, Nice machine, do it right. Nice clean 220 v line power into VFD.

Other machines will be happy on basic RPC..

That TB Woods, post a pic. There are different units under "E-trac" , made by different companies. It MAY be able to take single phase 230, depending on whose it really is.

abarnsley- could you provide a recommendation for brands that offer 220V single phase input VFDs in 5 hp that would work for the 10EE?
I've done some research and had come to the conclusion anything over 3 hp would require a 3ph input VFD derated. I'd be interested in checking out any single phase 220v VFDs that would not require derating.
I'd probably try to sell the Woods if there was any market for it. The toolmaster and bandsaw already have variable speed.
JST- working on the photo posting of the Woods unit.
Appreciate the help guys.

Many of the Invertek brand drives take single phase input. And they OEM for a number of others, including TB Woods, SEW, and others.

And Baldor, etc. Exact models available, change daily

Up to 50 hp.. Polyspede

You have to shop around.. Many are built with 7.5 hp front ends (diodes/caps), to handle 5 hp single phase..

Just checking the first model per brand, will miss the hidden gems.. Grind through all the models...

Already derated by mfg.. Not an it may work thing.. They will work..

Some VFD's have phase loss detection, and would show a fault if fed just single phase.. But of course some of those, can be tricked into operation..

Yes it takes some digging, but single phase input rated 5 hp to 50 hp VFD's, DO exist... Cost a bit more, but often less than an oversize 3 phase unit..

Photos of Woods ETrac

Ok, that's not a re-marked Invertek, don't know about it.

I have a WFC2010- 10hp Drive. Maximum single phase rating, 5 hp per my notes during a discussion with factory Tech. support. I would venture to say, your 5hp drive should be derated 50% also.

However, I have had a 7 1/2 Baldor on a 10EE run off this drive with no issues.

Paul

I also think this drive is only good for 2.5 hp driven with single phase. Felt like I was looking for unicorns for a while, but did find an AC Tech drive that was rated 5hp driven off 220v single phase. All others I saw cut off the non-derated single phase drive at 3 hp.

I think I am going to buy the American Rotary panel for $280 and pair it with the idler motor I have. If it works with the Woods drive, great. If not, I'll replace the VFD on the lathe and use the rpc for the remainder of the machines.

Looks like some people say the 7.5 hp Hitachi Wj200 drive can handle running a 5 hp motor (doesn't need to be 2x the motor or 10 hp). This option would be about 100 cheaper than the relatively rare AC Tech drive.