three phase motors

[clive griffiths]

I have got this motor and would like to know if it is possible to get it to single phase ,if not what power would I need to be able to drill around 40mm forstner bits , and are the machine mart motors ok.

Thanks.
Clive.

 

[Gordon Tarling]

You have two choices - either change the motor for a single phase type of the same power rating, OR you can run the 3 phase motor shown from a single phase supply by using an appropriate converter. Cost is likely to be similar for each, but using the converter will allow you a certain degree of control of the motor speed. What do you plan to drive with the motor? Your first photograph doesn't quite allow me to read all the data on that plate - perhaps you could try taking it again, from a slightly different angle? Whatever you do, if you're not experienced with mains voltage electrical wiring, PLEASE pay a professional to connect it all up for you.

G.

 

[Fitzroy]

The motor can be set up to run low voltage 220-240v but it will still require 3phase to operate. You can supply a false third phase an make it run using a capacitor, but this will reduce it's power significantly. You can run it off of an inverter, a piece of kit that will change your single phase supply to three phase. You can get a cheapo import from China etc from ebay for c. £50 or a more expensive one from for example DrivesDirect £200+. But without one of these mods, not it will not run on single phase.

Looking at the motor plate it is a 0.5kw motor, based on volts and FL amps. So a replacement 0.5kw motor should be up to the job. From memory the motor on my pillar drill is the same size and happily powers 50mm forstner bits. You could fit a 750w motor if you wanted to up the power, space on the drill permitting of course.

My table saw had a 3ph to 1ph conversion before I bought it and it has a Clark (which I think are Machine Mart) motor on it, and it seems fine to me.

F.

Edit : as Gordon said, if you're not comfortable with electrics please seek professional help 240v kills pretty easily.

 

[Ttrees]

Looks to me like you have a dual voltage 4 pole motor.
I can't see what HP it's rated for though, seems like it might be on the small side at 2.1a delta configuration, if your looking to use forstner bits.
Saying that I've not used good ones often.

You could run that with a VFD/inverter by the looks of things.
myfordman has an excellent write up on what you need to know if you wish to peruse it.
Not much to it if you read and understand that, just dont youtube it, some pure lethal advice out there.

Id also make a box for the thing from some sheet metal, so be on the lookout for some old appliances or whatnot if you have nothing lying around.

 

[Distinterior]

That looks like a Startrite Mercury motor & switch...?

 

[guineafowl21]

Looks like 370W, but not very clear.

 

[Distinterior]

I have the 240v version of that motor on my Startrite Mercury drill....Mine says 370w.

 

[Spectric]

Make life easy, just get a single phase motor and avoid complications and you will be drilling much sooner. Check if the shaft is metric or imperial though. The one addition I have added that has made life much easier is a footswitch, now I have both hands free to locate the drill bit and then without moving anything I can operate the drill rather than having to push a button.

 

[Sideways]

Ignore Machine Mart. Buy a TEC brand motor (good quality value made in Shanghai and with decent UK importers / distribution network) for the replacement.
Yours is a 370Watt (half horsepower), 4 pole. Plenty of retailers online.
Replace it with a 4 pole single phase with the same diameter spindle (so that the existing pulley will fit). If you can increase the power slightly to 550 Watts, that would be good but most importantly you need to have the same size spindle to match the existing pulley.

 

[JimmyStartrite]

MOTORS - Machine Spares

We sell the motors, original spec from original supplier (although a few name changes along the way), your rotary switch can be used on 3ph or 1ph, you just need to check you dont have an 4 step pulley which maybe metric

 

[Spectric]

Ignore Machine Mart. Buy a TEC brand motor

Yes good advice, you will get a better quality motor for probably less money.

 

[Myfordman]

A variable speed drill is a major improvement to a fixed stepped speed as with a simple turn of a knob/buttons you can drill at the correct speed without stopping to change belts apart from the very extremes of torque/speed requirements. You can easily get 10:1 or even 20:1 speed variation within each pulley step. For best results get a vector mode inverter.
Seems madness to steer away from these advantages and expense by going back to single phase and avoid any mismatch between pulley bore and motor shaft.

 

[heimlaga]

I am thoroughly sick and tired of home made motor replacements. Usually they end up with a motor that really doesn't fit in all dimensions and conclude that the machine is worthless to people like me...... who then struggle to find a motor that actually works.

 

[Fergie 307]

Personally I would keep the 3 phase motor and get a vfd. Cost will probably be similar but you get the added flexibility and functions that come with the vfd. I have several Huan Yang units good quality and very competitively priced.

 

[Spectric]

I am thoroughly sick and tired of home made motor replacements. Usually they end up with a motor that really doesn't fit in all dimensions and conclude that the machine is worthless to people like me...... who then struggle to find a motor that actually works.

A lot of these people think they want something that they really do not need, ie fully variable speed on a pillar drill using a VFD. My Atlas has the six steped pulleys to change speed, 90% of the time it runs 2200 RPM, I drop it right down if using a large morse taper drill bit or a flycutter. The reason they use a VFD is because they take a big risk and buy cheap so it appears cost effective, in reality a decent VFD is about £200 but that has full protection features and will not burn your workshop down, have seen too many incidents in my time because people cut corners, buy cheap products and then are not qualified to undertake electrical design and installation and then fail to undertake final testing to confirm everything is ok, because too many think if it works it is ok.

 

[JimmyStartrite]

Here here

If you want/need 1ph buy 1ph

 

[JimmyStartrite]

I am thoroughly sick and tired of home made motor replacements. Usually they end up with a motor that really doesn't fit in all dimensions and conclude that the machine is worthless to people like me...... who then struggle to find a motor that actually works.

Here here

If you want/need 1ph buy 1ph

 

[Fergie 307]

A lot of these people think they want something that they really do not need, ie fully variable speed on a pillar drill using a VFD. My Atlas has the six steped pulleys to change speed, 90% of the time it runs 2200 RPM, I drop it right down if using a large morse taper drill bit or a flycutter. The reason they use a VFD is because they take a big risk and buy cheap so it appears cost effective, in reality a decent VFD is about £200 but that has full protection features and will not burn your workshop down, have seen too many incidents in my time because people cut corners, buy cheap products and then are not qualified to undertake electrical design and installation and then fail to undertake final testing to confirm everything is ok, because too many think if it works it is ok.

I agree entirely that if you don't know what you are doing them messing with electrics is a bad idea, however I think you are a bit harsh in your view of vfds. As an example I have a Harrison lathe. Came with a 1.5 hp 1400 rpm 3phase motor, giving a top speed of 750 rpm. The machine is rated up to 2000 rpm. So I fitted a 2800 rpm 3hp motor running at 240v 3 phase. I have set up the vfd so it gives two speed ranges, 1400 rpm and the full 2800 rpm. I use the machines own 8 speed gearbox to vary the speed within each range, but now have 16 rather than the original 8 speeds, and a maximum of 1500 rpm. Courtesy of the vfd I also have soft start and jog facilities, both very useful as is the emergency stop. The vfd is a Huan Yang rated for up to 4hp and costing £130. I now have three of these running different machines, and have never had a problem with any of them. The same machine has a second small vfd running the coolant pump, in this case via a pot, so I can vary the speed, and coolant delivery, by just turning a knob. So they can be extremely useful, an enable you to retain the much smoother three phase motor on your old machine. This may not be quite so important on woodworking machinery, but certainly makes a difference on a metalworking lathe or mill.

 

[Spectric]

I can see your point, woodworking lathes being a good example because they do not have a mechanical gearbox but with a metal working lathe then having seen so much work produced on a standard machine using the speeds available with the mechanical gearbox I cannot see how intermediate speeds can really provide much benefit. Also softstarters are great on machines that start under some load such as pumps, compressors and conveyor systems but lathes and drills start with no load so using a DOL is fine. Personaly if I wanted to run three phase and could not get one from my DNO then I would use a digital phase convertor because they provide 400 volts three phase and could run multiple loads. Having seen the results from cheap, poorly installed/maintained equipment like VFD's and UPS systems that have gone into meltdown I think paying a bit extra for an ABB or Mitsi unit is well worth the money just for peace of mind, remember everything is always fine and problem free upto the point of failure.

 

[Fergie 307]

In the case of my machine, and many others, you could originally specify a single speed motor, typically 1.5 hp and around 700 rpm spindle speed, or a two speed motor usually 3 hp or more and up to 2000 rpm. Using the vfd enables you to replicate this very easily. And if you have a ten inch or more chuck weighing maybe 40kg, then I think that certainly qualifies as a load, and soft start is useful to limit the strain on the machine getting it moving. The vast majority of modern machines have this feature as standard, as well as things like electromagnetic brakes which can stop the machine dead in an emergency. I agree if you have multiple machines, and are happy to use the controls they have built in, then a digital phase converter can be a very good option, but a very expensive way of converting a single machine, and often on these old machines, mine dates from 1961, the original switch gear is sometimes a bit dodgy. A vfd can be a good way of resolving these problems as it is often simple to replace the original switch gear with more modern low voltage switches to command the vfd. This is what I have done in mine, the switches all look identical to the original items, but the clanky old wafer rotary switches have been replaced with modern ones. Vfd have been around for a long time and if you buy a decent make are perfectly reliable. I did have to chuckle that Huan Yang are now apparently suffering from lots of fakes of their products, presumably made by other Chinese factories, slightly ironic I thought!