3 phase

[Harbo]

I bought a 3 phase invertor from Ebay for about £80 to run my Meddings Pillar drill.
It works fine on small holes but struggles on deeper or bigger holes when more grunt is required.
I have spoken to suppliers at some of the shows and they all say that I need to spend about £300 to buy one that will work. It's much cheaper to buy a new single phase motor - which I did but have not got round to exchanging it yet!

Rod

 

[9fingers]

I guess inverters are like Marmite

People either love them or hate them!! :lol: :lol: :lol:

Bob

 

[Digit]

Personally I'd go for the cheapest. Frequently 3 phase m/c, new or s/h are cheaper, and once you've got your converter, you've got it.
No more changing motors then, plus speed control as a bonus.

Roy.

 

[ProShop]

The digital and electronic inverters will give you the full power of the motor
irrespective of the speed the machine is running at.

IMHO I would plum for the inverter solution, I have a few machines running
on these.

Unless you know the specific frame size etc as mentioned above and have the wiring skills to do the work as buying a motor getting someone in to rewire etc the costs are starting to mount up.

 

[bob_c]

Thanks for the replies, im reconsidering the single phase motor and instead leaning towards an inverter.Can anyone tell me what im looking at in regards to motor wiring in this picture.Is this the motor connection or is it underneath this.I expected to see the three brass strips i keep reading about.

Also a pic of the motor plate

 

[Digit]

Only if you can tell me where the wires on the R/H side of your pic go. With that number of conductors I suspect that pedal comes into the equation somewhere.

Roy.

 

[dickm]

From my (limited) experience, you might have problems with that motor. It says 400V on the plate, which implies it is star connected, and an inverter from 250v will only supply 250v (roughly) 3-phase. You'll need to get deeper into the motor to find the "brass connectors" the experts are talking about that can be shifted into delta configuration, IF indeed they are there.

 

[bob_c]

Ive found (i hope so)an inverter that converts from 1 phase 240v to 415v 3 phase,its used but pretty expensive when new.
The wires leave the box and go to that socket box thing on the side(the one with the german writing on in one of the previous pics above) the peddle cable also originates from this socket/box.

 

[bob_c]

Theres five wires that come from the motor,labelled 1--5,three red which i assume are the phase wires, and two blacks one.

 

[9fingers]

Bob,

I regret to say that I strongly suspect that this motor is permanently wired in Y configuration.
For it to be converted to 3 phase 240v operation it would need to have six wires coming out from the insides of the motor. I think you have three (red ones) being the 'arms' of the Y and a couple of black ones which are probably an over temperature cut out or perhaps some sort of brake as I think legislation now requires machines to come to halt in a maximum time.

All is not totally lost but you will need some expect help. The task is to open the motor, find the point where the 'arms' of the Y meet, separate them and bring them out on three new wires. This needs a lot of care and the correct high temperature wire to be used. A motor rewind shop might do this for you or they might decide the risk of damaging the motor is too high commercially to do it. What you need is a friendly chap who is willing to give it a go and you to accept the risk that the joint cannot be found.

The thing you needs to ask is " can they open the motor and bring the star point out on three new wires"

I've done several over the years and everyone has been successful and I would happily do yours too but I'm in Southampton and the carriage to send the motor could be quite high unless you can get it to me some other way.

Bob

PS the other way is to use the 240 -415v type inverters. These are not usually CE marked but still work OK but you will find some people turning thier noses up at this type (but not me!)

 

[bob_c]

HI Bob thanks for the reply,its getting a bit complicated and i dont really have a clue what you suggest doing.Ive ordered a cheap book from the workshop series on electric motors so i can understand it a bit better.
The inverter i was thinking of buying is a 240 1ph to 415v 3 ph. Its made by IMO.

 

[9fingers]

I've got Jim Cox's first book in the workshop practice series and it is very good. I've not seen the later one so don't know if it is an update on the first one or starts off where the first one leaves off.

He may well have a section on inverters to help you.

Bob

 

[ProShop]

looking at your photo of the motor info plate, it looks like the motor is Not dual voltage, so you'll need a digital inverter specially for dedicated 3phase motors, down side is they cost more. If your motor had been a dual voltage the standard electronic inverter would be OK and cheaper.

Have a word with Drives Direct 01773 811038.