Harrison M250 single phase to 3 phase power supply

I have just got a Harrison M250 3ph 415V 0.9KW/1.2Hp lathe. I want to run it off a single phase mains supply and understand that I need a converter of some kind to do this (rather than have to deal with wiring and possible motor change)

I'm getting a bit confused over options. I was thinking of using a Clarke PC20 2hp converter (feedback from some purchasers suggest ok for lathe use, however Clarke state that its not suitable for stop/start use even though it will be only used for light hobby use)

I'm not up to speed (no pun intended!) yet with the variable frequency devices such as the following:

https://www.amazon.co.uk/Single-phase-Three-phase-Frequency-Converter-Controller/dp/B088ZPQLSZ/ref=sr_1_13?dchild=1&keywords=single+phase+to+3+phase+converter&qid=1623068498&sr=8-13

I'm looking to spend about £250 maximum (hopefully) Can anyone advise please?

Malcolm

The 4kW VFD you link to 240v input with 380v output does seem to fit the bill but no data sheet provided to show what approvals the unit has so may not have RFI filters present.

Emgee

Phone Newton Tesla and speak to them.

Buffer

I suggest you talk to Newton Tesla. An important question is whether you can connect the motor in delta rather than star. If so the choice of inverter / VFD is wider and cheaper. On the motor there is probably a box where the mains cable enters through a cable gland, and the box should have a lid held on with screws. Take the lid off and take a photo of the connections inside, and another photo of the rating plate on the motor if you can see it. Then post the photos here.

I think the "static converter" approach is very yesterday's technology.

Malcolm, having just been through the research for a similar project, the basic bottom line (as I understand it) is this:

- A box that plugs into the wall and into which you plug your lathe is *possible*, but to be of adequate quality to not damage your machine and supply sufficient juice means well into four figures. The Clarke type boxes are electrically noisy and don't supply enough startup current under heavy load.

- The cheapest approach is a digital inverter (as per your Amazon link) which powers *only* your motor. If you have pump, lights, etc, these need rewired as necessary separately. The M250 is new enough that the motor will almost certainly be able to do this easily (don't be intimidated by talk of star and delta wiring, it's a matter of a few screws).

- Check your electrics! A surprising number of houses, especially older ones, have three phase right to the meter. If this is the case, it may be cheaper than you think to get it up and running.

Have a look at this, the price will be ex vat and postage. They have a quick start guide which can be printed out and it is even understandable for a dummy like me to follow and have a decent set of remote controls and easy programming. The vfd should be in a well ventillated area away from dust and swarf contamination.

**LINK**

That model is only 220v output, lathe has a 415v motor,

Emgee

Edited By Emgee on 08/06/2021 19:02:19

With the power OFF, remove the terminal box cover and you will see six terminals, three will be linked together (STAR mode), they are the three motor windings one end (1) and will be marked as follows if an older motor A1,B1.

and C1. If its a more modern one they will be marked V1,U,1 and W1instead. The other three terminals are where the original 415 volt would have been.

They all need to be reconnected as follows for an old motor, A1 to C2, A2 to B1 and B2 to C 1.

For the more modern motor V1 to U2, U1 to W2 and W1 to V2.

You can buy a Huanyang 2.2 KW inverter as my friends have done, from ebay for around £90 and the program on u tube. Should you need a copy I can send you one. John

Missing from the discussion so far is the question of what to do with the existing switchgear. There's a three phase contactor with a pushbutton starter and overload in there somewhere, which has become redundant. Not to mention the circuitry for a suds pump, also a lo-volt light, and a control voltage transformer and the associated fuses. Just strapping a VFD onto the motor terminals doesn't use any of the original stuff. Does the M250 have a two speed motor?

I assume the plan is to ditch the existing controls and have a dedicated pendant replacing their function. You can live without a suds pump, and the lo-volt light (converted to LED) could take its power from a wall wart of a suitable specification.

However, for my taste there is a much neater solution waiting to be built, namely converting the existing push button controls to be the VFD "Run" input, and something for the emergency stop function, also for the spindle direction. At its crudest the on-board red/yellow isolator switch meets the requirements for an emergency disconnector, though keeping the functionality of the E-Stop button would be a better alternative.

It would be a shame to scrap the existing original control panel completely, these controls need integrating into the new circuitry. It's a pretty little machine and it would be nice to retain its appearance.

If this machine is one of the ones with a spindle brake, the micro switch for this needs to be connected into the RUN circuit so the motor de-energises when the brake is on. There is also a comment on Tony's website about some of these having a kick stop switch, though this doesn't seem to have a brake function.

There's more to this than buying a VFD on ebay and pressing the ON button.

Simon

A branded drive like those from https://inverterdrive.com and the like is a far better solution than a "Huanyang" or similar from the far east via a unknown supplier on the internet.

Robert G8RPI.

I am not familiar with modern VFD devices, but I can tell you that I have been running a Colchester Student equipped with a two speed 3-phase motor off a Transwave static converter for the last 29 years with no real issues whatsoever and it was as simple as 'plug and play'. The lathe is stopped and started very frequently too. This converter also doubles as the power supply for a J&S 540 surface grinder and will run the wheel, hydraulics motor and extraction unit simultaneously without as much as a murmur. I also run a Harrison M1 mill from a separate Transwave and a Qualters & Smith hacksaw and Union industrial grinder from yet another Transwave which have all proved to be very reliable and virtually trouble free for many years.

One thing to check, if your Harrison 250 is equipped with a suds pump, is that it is connected to the 'broken' side of the NVR, not the 'live' side. My Colchester's sud's pump wasn't and without realising it, when the main motor was stopped, with the NVR open, the suds pump was still connected directly to the Transwave's output. However, such a low power motor could not trip the starting capacitance of the converter but just silently oscillated the pump until eventually it overheated and burnt out. I cured the problem by fitting a small auxiliary NVR to the suds pump but it had cost me a pump motor rewind in the meantime. This may or may not be an issue with a VFD device although you don't need a suds pump running at various speeds!

I thought I had replied to this yesterday, but must have forgotted the "add posting" button. A modern motor in star will be 415V, but when reconnected in delta will run on 230V three phase. See John Fletcher's post. My link also shows the motor connections. Robert Atkinson also recommends the same company.

Best you read the original post, states quite clearly 415v 3 phase motor and wants an opinion on the VFD linked in the post, he is not asking for recommendations to other suppliers, especially those who don't list an equivalent to his linked item.

As said in my original reply no data sheet included so perhaps there is no RFI correction unit fitted, but even on other suggested units, including the one you linked to, they are an extra which has to be ordered separately at additional cost.

You appear to have much more information about the motor than has been posted, how do you know it is a dual voltage motor ?

Emgee

Edited By Emgee on 09/06/2021 20:49:16