Haas Shrink fitter machine on VFD on undersize circuit?

So I recently bought a haas induction shrink fitter machine for my shop.

I didn't do my homework until it arrived and was surprised to realize it needed 220v 3ph. I realize that shouldn't be surprising.

I do have an RPC in my shop, BUT right now it's directly wired into my VF2, and it will be a logistical nightmare to add a subpanel just because of space constraints on the wall, I can do it if I have to.

BUT, right where I want to put the machine I have a 30 amp 220v 1ph plug on a dedicated 30A circuit. I was thinking I could put a VFD on that circuit to run the heat shrink machine.

Now, the shrink fitter says it will pull 30A 3ph, so that's significantly more than the circuit is rated for, BUT the maximum run time of the shrink fitter is 9 seconds, most of my tooling will require a 5 second heating cycle. I suspect it won't trip the breaker in that amount of time. Is it totally insane to think I can do this with the VFD?

Or should I just suck it up and do a multi-thousand dollar subpanel for the RPC and be done with it.

Most useful VFD motor drives REQUIRE connection to a legit electric motor to satisfy the internal brain checks.

I'm sure there are variations, but if your VFD has the ability to FAULT, it likely will on a heater.

I was worried that was going to be the case. Resistive loads and VFDs aren't compatible, it seems.

xnewmanx said:

I was worried that was going to be the case. Resistive loads and VFDs aren't compatible, it seems.

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Really dumb question (I know F-all about electricals), but could a 1:1 3ph transformer inbetween the resistive load and the VFD act as a (inductive?) "smoothing" function to allow a VFD to work? Or is there some other way to do it that's not crazy expensive?

I've used small VFDs for plain power supply before, in that case to test frequency-sensitive relays.

As long as it's in V/f mode, and has no undercurrent or broken-shaft checks engaged, it should be fine.

If the load cares about waveform, though, you'll need to clean it up.

Just as a follow-up, I sucked it up and ran a subpanel off my RPC. I also put the subpanel in a location that will be easy to wire up a lathe, should that day ever come...

You already decide, and probably took the best long-term path.

But, an induction heater should just be rectifying the incoming voltage, It may be fine with single phase, depending on the filtering and rectifiers. The kmakers would know.

normally there would be much less filtering when rectifying 3ph, probably the reason why they designed the PS for that thing that way, so I doubt it would be happy about the 1ph supply, not for long anyway

jz79 said:

normally there would be much less filtering when rectifying 3ph, probably the reason why they designed the PS for that thing that way, so I doubt it would be happy about the 1ph supply, not for long anyway

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Yes, 100% vs 14% ripple, as well as all the current on fewer rectifiers. But that is correctable...... and is not always even a problem The maker would know what the deal is.

No reason not to ask.

I have a switch mode lab power supply 0-24V and 0-80A, fed from single phase 240V (EU), and that thing will blow auto fuse (10A) once in a while when turned on, few big caps in there to provide the juice when the rectified single phase goes to 0... a more expensive one would probably have a relay and thermistors to charge them up slower, but this one doesn't, anyway, this same PS will blow the same 10A fuse when it goes over around 55A@22V, I measured amperage draw and the clamp on meter shows only 7.4A, so it must be the caps bottoming out, and once they charge + the inductor - the fuse trips

this same thing wouldn't happen with a 3ph rectifier, and probably wouldn't need those big caps either, and induction heater is somewhat similar to a switch mode PS, so I'd still think they'll say no to the 1ph supply