Running a 3phase at home

Another newbie one here any tips on getting a boxford 3phase machine running at home thanks

Buy a VFD so you can run it from single phase and get variable speed too. Endless threads on here giving info and advice.

Just make sure you get one with a dual voltage motor & all will be good.

It just means the 3 windings are 240v. Connect in Delta.

Steve.

I bit the bullet and installed a proper 3-phase supply as the old 60A single phase supply and fuse box needed replacing anyway.

Andrew

If you are just making the odd part for air rifles, a three phase supply is not really practicle.

I initially ran my 3 phase Boxford via a rotary converter, which meant there was no need to alter the wiring on the lathe at all and if the need arose, I could run other three phase machines from the same converter.

I still have the converter but went over to using an inverter. A cheap inverter plus a control box can convert the lathe to single phase for about £60, if you are competent enough to do it yourself.

My lathe now uses the original switchgear, plus a pot, one additional switch and a relay circuit to give variable speed, electronic forward and reverse, slow speed jog and braking. All the interlocks can be wired in simply enough to maintain the safety features.

Best tip I can give you is to write down two things: how much money you wish to spend and how much time you wish to spend.

If the first of these is a high number and the second a low number, the solution that works for you will be different to that if the first is low and the second is high.

Whilst I agree wholeheartedly with Andrew, proper 3 phase is the way to go. It does however depend a great deal on which part of the country you are in. In Hertfordshire, it cost a few hundred, but in Norfolk they wanted well over £50,000, so I'm stuck with a noisy rotary inverter.

Pete

noisy rotary inverter ! I used a citroen diesel car engine (free) and a 20Kva 3ph alternator(£110) To power my 3ph gear. The contol panel was the dearest part to make. Here I Norfolk we have NO 3ph in the village NONE ! some farms have 2ph. Noel

Noel

You are obviously not as sensitive to noise as me.

Pete

You could make an sound insulated enclosure but of course you would need to have temperature controlled forced ventilation, preferably to outside, but that's another motor noise.

Emgee

You certainly get a variety of suggestions on this site to your questions, for running your Boxford lathe on 3PH anything from a simple and cheap VFD to building your own power station.

Summarising posts above, you have three options

1) get true three phase installed by your utility company
+ Lathe just plugs in
- potentially very expensive
2) Install a rotary converter
+ Lathe just plugs in
- Noisy and takes up space
3) Convert the lathe to VFD
+ Low cost and adds variable speed with additional flexibility
- Some work needed to integrate the VFD and change control circuits to work with the VFD
That said there are preconfigured packages from people like Newton Tesla
- Potential issue if your motor can't be reconfigured for delta (240V) operation.

FWIW I went for option 3 with my Colchester Chipmaster, and got great help from Inverter Drive Supermarket in specifying exactly what was needed. They have a useful "how to" page Link

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With regard to Stuart's summary above, the VFD option is fine providing the motor on your machine is not too large. On my Harrison M250 lathe, I have fitted a 240v VFD which absolutely superb. The variable speed is used all the time, and even makes changing gears easier, when at minimum speed, (as opposed to turning the motor off).

The mill's requirements on the other hand are too large for a standard VFD, hence the rotary device. The picture shows where it started. It's now moved to an adjoining room, but I can still hear the dam thing.

To extend Stuarts list of possible approaches the Eaton DE-1 series inverters are a sort of halfway house between a full VFD and standard contactor type switchgear and rather easier to install.

Basically they are made to be used as an electronic replacement for ordinary contactors giving soft start and speed setting capablities. They are designed to be used via a simple power on/power off switch so you can easily use the original machine contactors. There is a full blown VFD in the box so you can do full speed control using a calibrated dial but the speed control is more aimed at providing at simple switched speed selection when needed.

A bit cheaper than brand name VFD boxes too.

Clive

If you are happy swapping belts to change speed, either swapping to a single phase motor or using a Static converter are cheaper options than a VFD + motor swap or rotary converter.

The 3 phase motor on my Boxford shaper was 415V only & the star point is buried deep - as I had a single phase motor with the same frame size to hand, I swapped out the motor. A bit "grumblier" in operation than a 3 phase motor, but it shifts metal just fine.

A Clarke PC20 static converter was purchased to run a small Ingar surface grinder with a single voltage 3 phase motor. This motor has a bespoke mounting flange, so easier to use the converter that change the motor in this case. If you sign up for MM's newsletters, they used to send out "Vat free" offers occasionally for Clarke products, which is how mine came about. It also runs a 3 phase RF30 mill drill - dual voltage motor on that one & a 240v output inverter is planned for it longer term.

At the time I bought the static converter, 240V in to 415V out inverters were not readily available. They do seem to be now, though the affordable Chinese (XSY ? ) units have both their fans and detractors.

Nigel B.

I always recommend the inverter drive supermarket for VFD's as they have their own "quick start guides" for many of their products. This link is for the one that I bought to run a 1hp motor. The prices get higher as the power requirement gets higher. The quick start guides can be printed out and make the programming and wiring very easy. So many people end up in great difficulties when they cannot understand the instructions that come with many VFD's. You would have to check your motor plate for its horsepower, (1hp is approximately 760W), and whether it can be run in delta to suit the common type of VFD.

**LINK**

Edited By old mart on 23/01/2021 15:41:33