Single to three phase

[SammyQ]

I've been given a nice meaty bench drill - it weighs more than I do - but it's three phase and I can't justify the outlay on a converter just for one tool. Anybody got EXPERIENCE of wiring and jigging to make 1 into 3 ? I know there is a book out there on workshop motors, but I'd rather correspond with someone that has actually put book larnin' into practice; I'd hate to fiddle ignorantly and start a power-tool-flavoured barbeque with side helpings of hand tools.

 

[74extiger]

I received a lecture yesterday on this subject from the electrician wiring my house and shop. Both are new construction. He advised me against 3 phase for my shop.

I was headed in that direction because at least two machines (my saw/shaper and dust collection) would run better on it. Or, so I thought. He told me I was wrong. Better depends on who you are, it would seem.

I thought 3 phase was better for bigger motors, and cheaper to operate for motors running all day long, such as dust collection.There is no advantage either in torque or operating cost in other motors.

I might add that this electrician just came off a job rewiring the big saws at the lumber mill just down the road. He works a lot with 440v, which is an industrial standard here in the US.

One advantage to a buyer of machines with 3 ph is that the motors are simpler and thus cheaper than single phase counterpars.

Since you already have the 3 ph machine you have two choices for getting your power converted over. You can buy one of those phase convertors that runs off a big motor. They are expensive and really needed only with heavy equipment. For a drill, do what my neighbor did to power up his Vertical Milling Machine in the Garage. Get an electronic phase convertor. These can be had for about $200 new here in the US. They buzz a little when turned on.

If you live in an industrial area, used motors off other equipment can be readily found. Just get the power rating and RPM appropriate to your machine.

My electrician said that every product associated with 3 phase costs 4 to 5 times as much as single phase. Such things as circuit breakers, disconnect switches, etc.

Gary Curtis - California

 

[Noel]

Sammie, know little about such things but you could talk to A1 Rewinds, Unit 14 Cido Business Complex, Carn Drive, Portadown. 028 38332280. Ask for Bill, who likes cash. He should be able to do a decent 2 hp, 2 pole 1 Phase motor for maybe a big note. You might have to take the 3 Phase unit down to him to ensure the mounting frames are the same. He does a lot of Weg brand motors from Brazil, nice big cast iron lumps. But he'll advise you what is best.

Rgds

Noel

1 nil.....

 

[PhilipL]

I've done this but with 1/2 hp motors (it's not too difficult or too expensive) using the fore-mentioned book. What size is the 3 ph motor?

Philip (Co Down)

 

[Anonymous]

I've been given a nice meaty bench drill - it weighs more than I do - but it's three phase and I can't justify the outlay on a converter just for one tool. Anybody got EXPERIENCE of wiring and jigging to make 1 into 3 ? I know there is a book out there on workshop motors, but I'd rather correspond with someone that has actually put book larnin' into practice; I'd hate to fiddle ignorantly and start a power-tool-flavoured barbeque with side helpings of hand tools.

I have both worked on and designed 3-phase kit for an embarasssing number of years

You have 4 choices only

1 replace the motor with a single phase one. be aware that the single phase motor will be larger for same power rating

2 use an invertor to convert 3 phase to single phase - expemnsive

3 get 3-phase supply into the house - £££££££s

4 buy a 6ft tall single phase drill stand for about £140 brand new

 

[SammyQ]

Firstly, apologies to everyone for not replying sooner; my family achieved the remarkable feat of causing the washing machine to catch fire......How the **** does 6Kg of washing and x gallons of WATER inside a STEEL drum go on fire? Well folks, it's possible and the smoke stains, melted plastic and general discombobulation aren't pretty.

Anyway, where was I? Many thanks to Noel for the address and PhillipL for the encouragement. From memory, the motor is 600watt; I'll check tonight. One way or the other I'm determined to get it going pronto.

 

[Losos]

Gary - Your electrician is right about the cost of accessories e.g. breaker switch, plugs & sockets etc. however IMHO the 3 phase motor is better i.e. it is more efficient & smother because there are three pulses (For want of a better word) for every revolution, single phase of course has only one.

Therefore, yes, it uses higher voltage, more expensive wiring etc., and can be more complex (Star or Delta config. I still don't fully understand the finer points of this argument) but in Czech Republic almost every house has a 3 phase supply available if people want to use it, and most do.

 

[CHJ]

...snip.. but in Czech Republic almost every house has a 3 phase supply available if people want to use it, and most do.

Same as Bavaria where my son lives. Most people run their cookers on 3PH. (440V in a domestic kitchen would give our Local HSE a coronary) It allows smaller gauge wiring to be installed to the houses for the same power consumption. Very handy in the workshop as long as you make sure all electrics are sound.

 

[PJ]

Sammie, IMO the easiest way would be to use a 1HP motor and a no-volt release switch from Axminster. The latter will not protect the motor but being rated at 750W and only being used on a drill press a 7A Fuse in the plug would sufice. All this for under £70. Just need to check the frame size and shaft diameter of the origional. If there is an old starter on the drill the check the coil voltage and if it is 240V you can use it and drop the no-volt release switch.
As Tony says, you can get a new drill for £140, but it certaintly won't be of a quality similar to what you have.
Hope this helps

Philip.