Rotary Converter and Single Phase Issues Fadal VMC 40

Hello All
I am having issues with my Fadal VMC. a little back story to start
Purchase my VMC 10 hp toshiba inverter standard machine wire 230 3 phase when purchased.
I do not have three phase power where i live so i went to rotary converter route i purchased my converter from ebay north american Rotary converters and installed my own Baldor Motor.
Machine ran fine for a few weeks until i took a few jobs on that i had to do some hogging. And i burned up my spindal motor And possible the inverter. Was told that i shouldnt use a Rotary converter on my machine because the Campacitors dont hold enough Power Supply to react fast enough when the motor is in and out of load... i have got many different opinions on the matter and was wondering if anyone out there has had similar issuse.

The Next problem i am facing is in the midst of working out the converter issuse i have been in the process of hooking the machine up single phase. It has a T 814 transformer in it and I have wired it in to the book. But Im having issues when it comes to the inverter I have a G2 Toshiba inverter. that calls for 3 phase power in. Again i have been told that these can run on single phase and they will generate the third leg. but im not getting any power or response from the inverter when i have juice going to it.

{Power into machine
120 V L1
123 V L3 from the shut off box

From Transformer in machine To the invertor
121 V L1
124 V L3 {here i have seen a few post about putting a Jumper Wire Between L3 and L2}

also i have to communitcation wires for the pin connector that i need to check into some more

I Have plenty of pictures if anyone has a Clue here Please let me know your opinions

I run my 4020 on an American rotary, no issues.
If you go single phase input, i believe you lose rigid tap function... if you have it.

Did you properly tap the transformer based on input voltages? did you monitor output voltages under load?

I cant help you with the single phase wiring.

If your looking to take decent cuts with it I dont think youll have much luck with direct single phase input. I think you will have more power running from a phase converter. I believe you only get 50% power with single phase input if you get it working. Its odd that your burned up your motor. If there was a lack of power you would think the drive would alarm out long before damage was done to spindle motor. Make sure the fan is working and it isnt blocked with chips or debris.

I run a 4020 off phase converter and it can take a pretty good cut but I have overloaded it and the VFD trips and gives a "supply voltage low" error. This is with a mitsubishi Z300 7.5kw drive. Fadal has used a million different types of drives, your might handle low voltage differently.

Thank you guys for your input i apperciate it. I did have the Transformer properly tap prior to running but i did not check while underload. i wish i had now. I was thinking the same thing as far as the VFD goes but all i got when the motor quit was OFF and thats all i could get it to do. Now Both of you said your using the same style Rotary. do you have voltage stablizers install or ive been told to put another Transformer in For a buffer between source and the machine. The single phase Route is kinda last ditch effort to get me up and going again but not a final solution. like i said im getting alot of differing opinions on the Rotary but it seems like you guys are up and running fine so i should be able to myself.
Do You know your Voltages under load By chance.
And did you have to unhook or install any More compacitors in your Rotary to get the Three legs balanced out better
Thanks again
Joe

I have an isolation transformer that I also use as a buck to drop the 250v i get out of my rotary down to 208.
I could get the voltage down by removing caps, but then was suffering line droop under heavier loads.
In my experience, the isolation transformer helps bring the wild leg under control, but im no electronics engineer.... cant explain why
It does create a nice buffer between the rpc and machines, improves rpc efficiency at idle and low load and acts as a bit of a ballast for fast heavy loads.

My electrician (I have him make things look nice after I have a proven concept) just shakes his head when he comes to visit. Says i have the nicest 3 phase hes seen outside of electronics laboratories.

macds said:

I have an isolation transformer that I also use as a buck to drop the 250v i get out of my rotary down to 208.

Click to expand...

"208" smacks of Delta-in, Wye-out. A goal of mine for both RPC AND Phase-Perfect, load side, albeit at 220 VAC Wye rather than 208. I reliably have 245- 246 VAC on the split-phase inputs, so ...

Phase Technologies doesn't recommend any other sort but Delta-Wye if a transformer is to go onto the output of a Phase-Perfect at all.

cant explain why

It does create a nice buffer between the rpc and machines, improves rpc efficiency at idle and low load and acts as a bit of a ballast for fast heavy loads.

Click to expand...

Another poster, in another thread, was opposed on the grounds that a transformer on an RPC's output "shared" some of the "badness" of the generated leg. Or words to that effect.

Well... that would seem to cut both ways, no?

If the generated leg gets some slight improvement, or even NO improvement, out of the exchange in a common-iron 3-P transformer core, but the other two legs are dragged down? There is at least a bit of "leavening" effect that reduces the differences.

I'd call that a plus, not a minus, and your experience supports that.

I'd be interested in which specific transformer - or its specs - was used as well. I haven't purchased mine yet.

Thermite, its a Hammond DM027BC
I tried finding it online, but no luck.
27KVA, aluminum windings. Type K
Dry type isolation drive isolation transformer.

Found it... Drive Isolation Transformer (Gen. 1) | HPS | Hammond Power Solutions

macds said:

Thermite, its a Hammond DM027BC
I tried finding it online, but no luck.
27KVA, aluminum windings.

Click to expand...

Thanks, I'm a Hammond customer, have catalog & data sheets around on-disk. Somewhere.

I'm working with but 10 HP, 1 X RPC and 2 X Phase-Perfect. Goaling to do but one of the two P-P, as one is brand-new, the other the old "blue case" and of uncertain remaining service life.

Belt, braces, designer long-johns and body-paint redundant, the MEP803 Diesel gen set can be dialed-up to 10-12 KVA @ 220 VAC Wye on the panel, too - not just 208.

Im actually running an isolation transformer too. The voltage from each phase to neutral is not right coming from a phase converter. You get 120, 120 and 208 I think. The generated phase is higher for sure. Running it through an isolation transformer fixes this problem. It gives the proper output with the right voltage from each phase to ground.

I think this is important if your CNC doesnt have a built in transformer. Our Fadals do of course so I think this problem gets taken care of by the Fadal transformer anyway. So we probably dont even need the isolation transformer. My phase converter was bought used and came with the transformer so I hooked it up anyway. Might be just wasting electricity for nothing, but it is working at least.

An RPC will almost always have a phase to neutral offset difference which an isolation transformer corrects. Some equipment requires a neutral thus needing a wye connected transformer output. I was a Hammond distributor years ago and this is a fairly complicated subject requiring an experienced industrial electrician or someone willing to spend time and really learn 3 phase power. As for efficiency these transformers are good enough that it is very difficult to actually measure their losses which are more than offset by other factors such as a cleaner waveform and significant suppression of high frequency spikes.