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Help with 575V 3Ph Hardinge-HLV-H

Hello PM members,

I purchased a Hardinge HLV-H that is in pretty good shape for a great price, but made the mistake of not verifying the voltage because I got carried away with the price.

I know that I can swap the motor and coolant pump for 3ph 220V motors, but if I can get a way with using a step up transformer I would rather go that route.

After doing some math and verifying with an electrical engineer, I will need a step up transformer with 3.42KVA minimum. I think the common size available is 4KVA, but I can't find a source for one. Does anyone one have any inputs or sources for step up transformers? I'm ok with buying a used transformer.

Transformer Requirements

Input: 220V 3ph
Output: 575V 3ph @ 2.4 amps

Any input is greatly appreciated.


Active member
Here's a link to the open-delta design I built to power my 575-V Aciera F5 that has a 4-hp spindle motor and 1-hp feed motor. I bought two single-phase 600-240V transformers online and wired them backwards. One was used and the other NOS, otherwise same brand and ratings (5kVA each). I think one came from an electrical surplus seller and the other from eBay, but I forget. I have since traded up from the RPC shown in the diagram to a PhasePerfect. This post also had good advice.


Active member
More of a question, can buck boost transformers handle that 240 to 575 volt step up? I used a pair of buck boost transformers to go from 250 to 230 and was surprised how inexpensive that was. Yeah, only 2 were needed for 3 phase.

If you were to find a damaged HLV-H lathe with good motors remember the speed change motor is also 3 phase and would have to be changed also, as well as the inside transformer for the control circuit.


Active member
To my understanding, buck-boost only applies to less that about 10% voltage shift, not 240%, and the transformer only has to support a fraction of the load current.
Well, I am going to have to read up on open delta configuration, because I have no clue.

I did find a step down transformer on eBBaayy with the following specs:


Supply Voltage - 440-480V LB / 500-575V LA.
Output Voltage - 210-240V 3-Phase. 200-230V Single Phase. 50/60Hz.

Do you think it can be safely ran it be ran backwards?


Active member
With the limited amps being drawn on 575 volts with these small motors in an HLV-H I would think backwards would work. You might find a better answer in the Transformer, Phase Convertor section just below gunsmithing. My feeling on this is only a guess.


Active member
I can't think of a reason "backwards" would not work, as long as you stay within the voltage and kVA limits.

stephen thomas

Active member
I built such a 575 system since some of my heavy woodwhacking tools are that voltage.
Some of my metal shop machines also are on a transformer, since they are 440/460V

Buck/boost might work for you, a Hardinge HLV- is a lot less amps than a Deihl lumber jointer with all 3 motors running in heavy stock. :)

You are in NY.
Anywhere near Geneva?
I like M & M for surplus electric stuff, when there is less time to shop in scrap yards and such less likely places these days.
They are fair priced. Not give-away, though. Maybe 50% new? for near new equipment? Maybe less. Also, in the past, helpful (been a few years for me)

You have to google M & M Electric surplus, Geneva, NY.
They don't have a website.

(When you google, Ignore the current brouha - slagging and attempts to tear him down over the "gun rights issue"
He thinks there should be background checks, and if you are an NRA member who shops in his store, he wants to have a conversation with you about why not?) Personally, I'm in favor of gun rights, but I'll support him over that. & his first amendment rights.

As they say, your politics may vary.
I've had good experiences in the past, including a transformer buy.

Unfortunately I am about 5hrs away from there.

Thanks everyone for the replies. I am going to do some more research before I purchase anything, I am trying to wrap my head around transformers and their application. The more I read about it, the more I find contradicting info on the subject.

stephen thomas

Active member
Here's the link to when i built the 550 unit for my wood shop:


Here are the missing photos:


Note the label above, and reading my old post, by using a 208 transformer, but feeding if from modern aprox 240v supply, on high taps the uncorrected legs yielded 560 to 590V output. Well within range of a 575 that should run fine on +/- 10%. In fact, i settled on using the #2 taps for my machine. Also partly inconsideration of keeping any spikes under 600V where another class of insulation might be necessary. Then the legs were balanced with run capacitors, with the machine running, but no load. As stated in the old post, The Deihl behaves as if it is on electric company supplied mains. No issues.

Just be careful for the integrity of your grounds, insulation, breakers.


(Above) My woodshop convertor feed a regular 3ph service panel, and then is distributed through breakers from that to the various circuits and machines. That is why i'm tuning the legs for the Diehl, at the panel, where it is on it's own 3ph breaker. When i had made a determination which/how much capacitance to use, the capacitors and wiring went into the open plastic device box just under the 3ph panel. The (door closed) single phase shop panel is to the right. If you have 3ph mains power, your installation will be much simpler. And you will not have to balance the legs. Just find the taps on the transformer that get the voltage where it needs to be.