Haas UMC-500 with Phase Converter

Howdy all, I'm new to the phase converter game and have some questions.

I currently have a UMC-500 which Haas rates at 30hp in my barn which I was hoping could be powered by my American Rotary AUL-75, which is rated for 37.5hp.

The AUL-75 requires a 200amp breaker, that doesn't leave me any wiggle room for spare amps, as I currently have a 200amp service coming into the barn. I'm planning on upgrading to a 400amp service later this year. Until then, I need to get this spindle turning!

So I was wondering what your thoughts on running a AUL-40 {125amp breaker) until I can upgrade my service. I take light and fast cuts and rarely see spindle loads if ever above 25%

Thank you!

jared.l24 said:

Howdy all, I'm new to the phase converter game and have some questions.

I currently have a UMC-500 which Haas rates at 30hp in my barn which I was hoping could be powered by my American Rotary AUL-75, which is rated for 37.5hp.

The AUL-75 requires a 200amp breaker, that doesn't leave me any wiggle room for spare amps, as I currently have a 200amp service coming into the barn. I'm planning on upgrading to a 400amp service later this year. Until then, I need to get this spindle turning!

So I was wondering what your thoughts on running a AUL-40 {125amp breaker) until I can upgrade my service. I take light and fast cuts and rarely see spindle loads if ever above 25%

Thank you!

Click to expand...

cant be that fast since its a haas...

I run several machines with REAL 30HP spindles on a 60HP RPC. I have had to adjust accel parameters on the bigger machines, but steady state is fine on an RPC. Fanuc rates their drives to pull 200% of the max nameplate current on acceleration. New Fanucs are set to full kill from the factory. They accelerate from zero to max spindle speed in 1/255th of a second with the only limitation being the max amps. If the machine's nameplate amps is 100, then the spindle is allowed to pull 200 amps on startup.

If Haas still runs braking resistors then you shouldn't have any problems with running it on an RPC. RPC's don't do well feeding power back into the grid. If it doesn't use braking resistors you may need to slow decel down or current limit regen.

A great way to gauge how much power a machine actually needs is to look at the size of wire going from the main breaker inside the machine. Look up the wire on an ampacity chart and that's your absolute maximum the machine builder will let it pull.

I never had any luck running an RPC through a circuit breaker. My 60HP RPC will draw up to 180 amps single phase so I have it plumbed straight to the buss bars in a 200 amp sub panel with copper crimp lugs on 2/0 welding cable. If I overload the RPC it will trip the main 200 amp breaker.

If your UMC actually has a 30HP spindle you will have to do something similar, but I'd bet real money it has nowhere near a 30HP spindle.

jared.l24 said:

Howdy all, I'm new to the phase converter game and have some questions.

I currently have a UMC-500 which Haas rates at 30hp in my barn which I was hoping could be powered by my American Rotary AUL-75, which is rated for 37.5hp.

The AUL-75 requires a 200amp breaker, that doesn't leave me any wiggle room for spare amps, as I currently have a 200amp service coming into the barn. I'm planning on upgrading to a 400amp service later this year. Until then, I need to get this spindle turning!

So I was wondering what your thoughts on running a AUL-40 {125amp breaker) until I can upgrade my service. I take light and fast cuts and rarely see spindle loads if ever above 25%

Thank you!

Click to expand...

My guess is that you will be fine running a AUL-40 on a UMC500. I suspect that you may not need to upgrade to a 400amp service...unless you really want to. I have a VF2 with a 10000k spindle and an SL10 with a 6000K spindle. I run these on a 20HP RPC with a 100 amp sub panel with no issues. Sometimes I watch the amp/watt load while the machines are running. Its surprisingly low on the mill...like under 15 amps running a 1/4" EM. Never close to the claimed max load. The lathe has a bit more going on...hydraulic pump and the variable of different mass in the spindle to ramp up. On my classic control machines I can dial back the acceleration of the spindles if I need to. I typically keep these settings at default and have never needed to slow things down with my 20 hp RPC. Your UMC500 NGC control gives you a little bit less flexibility when it comes to changing spindle acceleration settings. If you run into issues with your AUL40 you could always ask haas to dial back your spindle accelerations some. I believe with NGC you can also pay a fee to unlock some of these parameters that were previously available with classic control. At any rate, I am guessing the UMC will run fine on a 40 hp RPC.

Cool, thanks for the help so far.

@Garwood, may I ask what size your overall service size is? I'll check the gauge of that incoming wire, great idea.

@Turbo422, I'm planning to expand with a vf-2 and some kind of cnc lathe in the coming months, so that's why I purchased the aul-75 initially.

Whats strange about all this is, my electrician hooked up the AUL-75 RPC with a 125amp breaker, it worked great for a few days. The machine was not hooked up yet, but the RPC started smoothly and sounded great. My Haas tech arrived yesterday to finish the install, and of course the RPC kept tripping the 125amp breaker! So back to the drawing board. Again I currently have a 200amp service and my panel (GE THQL style breaker) won't allow me to run a breaker larger than 125amps unfortunately, or so my electrician says?

The easiest solution I can come up with is ordering a AUL-40 for now.

jared.l24 said:

Cool, thanks for the help so far.

@Garwood, may I ask what size your overall service size is? I'll check the gauge of that incoming wire, great idea.

@Turbo422, I'm planning to expand with a vf-2 and some kind of cnc lathe in the coming months, so that's why I purchased the aul-75 initially.

Whats strange about all this is, my electrician hooked up the AUL-75 RPC with a 125amp breaker, it worked great for a few days. The machine was not hooked up yet, but the RPC started smoothly and sounded great. My Haas tech arrived yesterday to finish the install, and of course the RPC kept tripping the 125amp breaker! So back to the drawing board. Again I currently have a 200amp service and my panel (GE THQL style breaker) won't allow me to run a breaker larger than 125amps unfortunately, or so my electrician says?

The easiest solution I can come up with is ordering a AUL-40 for now.

Click to expand...

My service is supposedly 400 amps @ 240V single phase, but my pole transformer is just 45 KVA so I think that sets me to a max of 200 amps.

Like I said above, I could never get a 100 amp breaker to work. The breakers would trip frequently and then catch fire. And this was when I just had a 30HP phase converter.

My recommendation would be to keep the larger RPC, but install it without going through the panel if you must have an electrician do it to code. You would do this by installing a stand alone disconnect with either a breaker or fuses. The disconnect would be connected to whatever feeds your current breaker panel.

A common misconception is that your breakers total capacity needs to be under the size of your service/main disconnect capacity. That is not true at all.

30hp... check out the D/Y contacts in the machine

We run all of our "small" haas machines including the 500 15k on 40 amp breakers with 8awg feeding them, some 100ft runs from the panel.

...30hp, give me a break

And as of 2020 the UMC500 has a resistor brake so should be find on a phase converter

Garwood said:

My recommendation would be to keep the larger RPC, but install it without going through the panel if you must have an electrician do it to code. You would do this by installing a stand alone disconnect with either a breaker or fuses. The disconnect would be connected to whatever feeds your current breaker panel.

Click to expand...

^^^ that if you need the full beans

Turbo442 said:

Your UMC500 NGC control gives you a little bit less flexibility when it comes to changing spindle acceleration settings. If you run into issues with your AUL40 you could always ask haas to dial back your spindle accelerations some. I believe with NGC you can also pay a fee to unlock some of these parameters that were previously available with classic control. At any rate, I am guessing the UMC will run fine on a 40 hp RPC.

Click to expand...

The "service key unlock" thing is a ~$500 option and I think it offers the ability to slow down spindle acceleration. I can check on this tomorrow.


Spindle acceleration is where a potential issue could come up once the RPC setup is happy. The machine will throw a low voltage alarm and reduce rapids temporarily as the voltage sags during wind-up. Either way, even heavy cutting on a machine like this is like 10-15amps... or 30 HaasPower

I just wanted to update this for the Archives.

The AUL-40 / UMC-500 combo has been flawless over the last 6 months. I've mostly been cutting Titanium and no hiccups to speak of.