Alex Wong1697456877 Posted August 8, 2005 Share Posted August 8, 2005 I've got a bench drill with a three phase motor on it but only single phase electricity. Should I get a new motor? what about using a converter - pros / cons? Thanks Link to comment Share on other sites More sharing options...
oilyhands Posted August 8, 2005 Share Posted August 8, 2005 Convertors/transformers are expensive and heavy. Maybe a motor would be cheaper. Dave Link to comment Share on other sites More sharing options...
Foxy Smith Posted August 8, 2005 Share Posted August 8, 2005 Unless you are planning to buy lots more 3 phase equipment a convertor doesn't make sense. Unless it's some kind of monster drill a single phase motor is fine. I think what's referred to as TEFC is best for workshop use. There are ways to make a 3 phase motor run on single phase but I believe it depnds on the type of motor you start with and it involves big capacitors and such like scary things. New motors are easy to come by and whats more important can be specced with the correct spindle size and keyways(if used) to suit your existing pulley block. All you have to cobble up is a mounting bracket. Link to comment Share on other sites More sharing options...
John Howe Posted August 8, 2005 Share Posted August 8, 2005 Alex, Foxy has said it all... I went the new motor route some ten years ago, and that was with a spark in the family. JH Deliveries by Saffron, the yellow 230bhp Sausage delivery machine Link to comment Share on other sites More sharing options...
Alex Wong1697456877 Posted August 8, 2005 Author Share Posted August 8, 2005 Thanks! Will go motor shopping then. Link to comment Share on other sites More sharing options...
jackb_ms Posted August 8, 2005 Share Posted August 8, 2005 If you can isolate the 3 coils it is very easy and cheap to modify it to work on main. You could even have a reverse. What you need is an ohmmeter to isolate the coil and an AC capacitor of around 10 to 16 micro-farad (can supply those, about £5). Some of my bigger sliding motors are three phase motors converted to work on a single-phase power supply. Jack Emily, The Very Yellow 21 Link to comment Share on other sites More sharing options...
Foxy Smith Posted August 8, 2005 Share Posted August 8, 2005 Jackb_ms, is there not an issue about starting these motors when they are converted to run like that? If it really is that easy I'd like to know a bit more about it as I have a pile of 3 phase motors looking for jobs to do! Link to comment Share on other sites More sharing options...
jackb_ms Posted August 8, 2005 Share Posted August 8, 2005 For big sliding gate, from 1.5 T, they are all 3-phase motor converted to single-phase use. To start any single-phase motor you need to have a capacitor. The motor inside a washing machine are single-phase motor and the big white cylinder on the side of it is a AC capacitor. I will dig my electromechanical engineering and find out how to calculate the size of the capacitor. If you have a 3-phase motor you can have a forward and a reverse or two forward speeds Jack Emily, The Very Yellow 21 Link to comment Share on other sites More sharing options...
jackb_ms Posted August 8, 2005 Share Posted August 8, 2005 Foxy I've found all the info needed. If you want to e-mail me please do so. There is a bit of physics and an electrical diagram to understand, but it is not rocket science Jack Emily, The Very Yellow 21 Link to comment Share on other sites More sharing options...
Don Cook Posted August 8, 2005 Share Posted August 8, 2005 I bought a phase converter. Cost about £150 but has tremendous capabilities. Can give soft start so you can run a much bigger drive from a 13A socket (starting current is much lower) you can control the speed from almost zero to about 8 times normal (if the drive can take it) has dozens of characteristics to allow different voltage / current relationships and loads of interesting things. As well as all that I now have the flexibility of buying single or three phase gear. Most of the time second hand three phase is far cheaper than single. I run a Colchester master lathe, a senior milling machine and a couple of smaller machines of one converter (not all at the same time). I certainly would look at the converter before limiting my options with an expensive new motor. Link to comment Share on other sites More sharing options...
Rob Morris Posted August 8, 2005 Share Posted August 8, 2005 Alex, Agree with the comments.........change the motor. Link to comment Share on other sites More sharing options...
Alex Wong1697456877 Posted August 8, 2005 Author Share Posted August 8, 2005 Don, I looked at the converters and thought pretty much what you wrote, yet everybody else seems to feel a change in motor is a better idea. Which converter do you have? Alex Link to comment Share on other sites More sharing options...
Foxy Smith Posted August 9, 2005 Share Posted August 9, 2005 Alex, Don's comments have caught my attention too. The cheapest converters I have found suitable for my needs (Heavy woodworking gear) have been around the £600-700 mark. I have just found a company drivesdirect.co.uk which can supply a converter which sounds like that described by Don. The problem is it depends on your three phase motor being of the dual voltage type i.e. 240/420V which is no good to me as my needs are for single voltage type. May be of use to you however and could well be cheaper than a new single phase motor. Hope this is of help. Alan Link to comment Share on other sites More sharing options...
Alex Wong1697456877 Posted August 9, 2005 Author Share Posted August 9, 2005 I've been looking on their site as well (they sell alot on e-bay). I might have a chat with them. As previously mentioned, second hand 3-phase stuff is pretty abundant and one day, I'd like a lathe and maybe even a milling machine. Edited by - Alex Wong on 9 Aug 2005 09:04:33 Link to comment Share on other sites More sharing options...
Area Representative Richard Price Posted August 9, 2005 Area Representative Share Posted August 9, 2005 Alex, how big is the motor? Single phase to 3phase inverters like these heremay be worth a look. A local wholesaler may well do a good deal for cash. The primary use of these is to provide variable speed of otherwise fixed speed motors. When I was an apprentice, I remember early inverters of this type of power output costing over £3!!! Edited by - Richard Price on 9 Aug 2005 18:03:49 Link to comment Share on other sites More sharing options...
Don Cook Posted August 9, 2005 Share Posted August 9, 2005 Hello chaps. The unit have is a T-verter N2 type. I bought it whilst living in Holland I find it superb. There will be a UK distributor but I don’t know who. You see them coming up on E-Bay quite frequently. You can get some idea of the features included here> http://www.sinolec.co.za/inverter/n2.htm Cheers. Link to comment Share on other sites More sharing options...
Don Cook Posted October 6, 2005 Share Posted October 6, 2005 Alex which way did you go ? Link to comment Share on other sites More sharing options...
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