Connverting 3 phase drill to single phase

sarabande

sarabande

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I am looking at a used pillar drill on fleabay. It's the right model in reasonable condition, but 3 phase (I guess about 750W).

Is it difficult to convert to a 'normal' single phase, in terms of the wiring ? If I buy a comparable new motor, do I 'just' swap them over, or are there ferociously skilled things I have to do to the cabling and switches, please ?

Or do I go for a hassle-free new bench drill for a bit more money, replete with all the modern safety stop buttons, and chuck guards, etc ?


thanks.
 
sarabande said:
I am looking at a used pillar drill on fleabay. It's the right model in reasonable condition, but 3 phase (I guess about 750W).

Is it difficult to convert to a 'normal' single phase, in terms of the wiring ? If I buy a comparable new motor, do I 'just' swap them over, or are there ferociously skilled things I have to do to the cabling and switches, please ?

Or do I go for a hassle-free new bench drill for a bit more money, replete with all the modern safety stop buttons, and chuck guards, etc ?


thanks.
Click to expand...

Long, long ago I did a project at school that involved creating a motor that used a three phase supply (I built a tiny linear motor!). I investigated ways of creating a three phase supply from the single-phase mains available in the school laboratories, and came to the conclusion it was too complicated and costly. I wangled access to the three phase supply - I'd never have got permission these days!

Basically, if it uses a three-phase supply, the motor probably depends on the three phase nature of the supply to work at all - the three phases are used to create a sort of travelling wave round the stator of the motor. Converting single-phase to three-phase requires serious electrical engineering; this site (http://www.motorsandinverters.co.uk/1Phase-in-3Phase-out-c23/) has a selection of devices - I note that they run from £100 up - about £150 for one capable of running your drill.
 
I bought an old large power hacksaw for $50. The problem was it had a three phase motor. It is possible to convert a three phase motor to run on single phase. I am certainly no expert but I am sure I have seen an article on the Internet which explains how to use capacitors.

I had a washing machine motor which I hooked up to the power hacksaw and it worked alright but I had to give it a hand to start up. Then I added a second washing machine motor and it works perfectly!! Where there's a will there's a way:triumphant:
 
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Buy and fit a single phase motor. There are so many cage sizes etc that you would find a good fit without too much trouble. Getting the pulley & shaft diameters correct might actually be trickier.

ps Decent solid pillar drills are worth having if you can get one
 
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ParaHandy said:
Buy and fit a single phase motor. There are so many cage sizes etc that you would find a good fit without too much trouble. Getting the pulley & shaft diameters correct might actually be trickier.
Click to expand...

One HP single phase motors 1400RPM would cost over $A200 in Australia
 
Hi Sarabande there is lots of chat about this on the MIG welding forum.
If you want to have pride in your machines go for the old one. What is it, a Meddings? Belt or gears?
Can you see it working, can you check the play in the bushes?
I know you are farming so guess you have a bit of space and appreciate solid engineering which will outlive you.
The new chink **** won't give you any pride of ownership, never mind the built in obselesence.
It's a no-brainer!
 
jerrytug said:
If you want to have pride in your machines go for the old one. What is it, a Meddings? Belt or gears?
It's a no-brainer!
Click to expand...

My power hacksaw has a huge pulley and belt drive. I've cut through a 50mm s/s shaft: I should walk away and leave it (it has auto cut out) but I stay there and just watch it!. Right now I'm fixing up a 140A Transarc Easy Welder that I found on the rubbish dump. I get a kick out of doing things like that:excitement:.
 
Local scrap yard is your friend. My company suffered a 2 phase drop out- (i.e. 2 phases went low voltage but the third stayed up).

Most machines shut down safely but my compressor struggled along on one until it burnt out.

A trip to scrap yard sourced two;- one was brand new but damaged on its arrival, the other used.

Both worked, total cost £15.

Take a meter with you and check for interphase connections and short circuits.
 
you need to swap the 3 phase motor for a single phase one, but you need to try and match the original motor RPM or all your gearbox speeds wont match, dependant on the original motor rpm this might be tricky. also the mounting and bolt pattern probably wont match, although if you complete this and it works you have the satisfaction of completing the project...........It might be better just to buy a single phase drill in the first place
 
As said, 3-phase converters are available.
A problem with replacing a 3-phase motor with a single phase one in old industrial machinery can be that, for similar power, the single phase motor will be physically larger and probably less starting torque.
Check before you buy!
 
earlybird said:
As said, 3-phase converters are available.
A problem with replacing a 3-phase motor with a single phase one in old industrial machinery can be that, for similar power, the single phase motor will be physically larger and probably less starting torque.
Check before you buy!
Click to expand...

True, but you might get away with a little less power for occasional use.

My pillar drill came from a machine tool recycling centre and it has a second hand single phase motor that cost me £5-00!
 
prv said:
Since they're only added for the euro market, they generally unbolt easily and without affecting the operation of the machine.

Pete
Click to expand...

haha reminds me of someone in my class as school. While dangling his tie against the chuck he started the sentence "I don't need to tuck my tie in, it's not like it'll just catch". As luck would have it he was at least smart enough to know where the big stop button was :)
 
Using a single phase supply would be easy, we know the speed of electricity in cable and the frequency of the mains power so simple maths would tell you the length of two pieces of cable to offset the other phases. It's probably a lot of cable though ;)
 
If you plan on any more machinery that might be three phase, now is the time to invest in a decent sized inverter, if not then hunt eBay for a cheap 240 v motor.
 
OK, just a bit of feedback. After PMs from 2 forumites with significant experience in these matters, I am going for a new one (a Warco). £££ hurts, but as it is a business buy, I should get the money back in a year or two (unless I lose the receipts box again :( ).
 
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