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9th May 2020, 05:13 PM #1New Member
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Single phase motor for Colchester 'Triumph'
I recently bought a 1950 Colchester 'Triumph' lathe, it has a 3 phase motor and as I only have single phase I need a new motor; the old motor, is 2.2 HP and ran at 1400 (or so) revs.
E-Bay has lots of single phase motors, in fact an excess of ones that appear to a person (me!!) that has an embarrassingly limited knowledge of things electrical, to maybe be what I need.
Could someone point me in the right direction?
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9th May 2020, 06:04 PM #2
Hi Eoin,
Welcome to the forums !
Don't bother with changing the motor, just get a VFD ! Easier and cheaper ! It will convert single into three phase and give you variable speed to boot. You will need to change the motor from star to delta first. This can usually be done in the wiring box on the side of the motor.Best Regards:
Baron J.
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9th May 2020, 06:07 PM #3Most Valued Member
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Based on the speed you nominated, your existing motor is 4 pole.
A motor that has the same rated power, and has the same mounting and shaft dimensions in 4pole single phase is what you are looking for.
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9th May 2020, 06:21 PM #4Most Valued Member
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A lot of older three phase motors don’t have the far end of the windings extended to the terminal box, none of the six machines I’ve had that were purchased with three phase motors were capable of being reconfigured to Delta in the terminal box. If both sides of the windings are not there, it’s a $300ish trip to a motor rewinder. You will get some limited speed control via the VFD yes, but not the silver bullet never have to touch the pulleys/gearbox ever again type deal. And right at the moment with supply lines to Mao’s dollar shop restricted, a VFD isn’t that cheap.
A VFD is great if you want a project and learning experience in its own right. If you want to make the lathe turn to crack on making parts a direct replacement single phase motor is hands down cheaper and easier.
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9th May 2020, 08:59 PM #5
Vfd
I've tried a few older pre-1960's lathe motors with a VFD and it just isn't a good result, something to do with the older motor characteristics that make it struggle and unworkable. Modern motors are usually OK with a VFD .
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9th May 2020, 10:00 PM #6Senior Member
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While not an electrical response, this is just a heads up on using the variable speed function of a VFD on lathes that have an co-driven oil pump for headstock lubrication, its possible to slow down to the point where there is no more lubrication. A splash type headstock, less of a problem. Unsure of the Trimpuh setup but my Master 2500 has a separate oil pump. Alan.
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10th May 2020, 12:50 AM #7Diamond Member
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G'day Eoin, While I would normally say that my advice would be to install a VFD, (variable frequency Drive) sometimes called a VSD, the S standing for speed or simply an inverter drive, they are all one and the same thing, but there are some valid reasons why you might choose not to. Both Racing Tadpole and Morrisman have listed some good reasons for not going that way. As Racing Tadpole says, installing a VFD can be a project in itself, some rewiring of your lathe will need to be done to avoid damage to the VFD, as they don't like having the load disconnected between the drive and motor. To stop, the VFD needs to be told to stop the motor from its own control inputs, not just having a switch between the drive and the lathe motor thrown. Although this entails some work, you can take this opportunity to incorporate previously unavailable features, like soft starting, jogging, emergency stopping and wide speed variation for the times you find it handy.
Another reason to go the VFD way, is that mechanically it may just be easier. If your lathe has a drive train like this one from the Early Colchester Triumph Drive System site, you may be in for a tricky retro-fit of a modern motor, it may just be simpler to retain what you have unless multiple dismantling and re-assembly of the drive train just so you can make bits for the job of adapting new parts to old doesn't faze you.
Having said that a VFD and a VSD and an inverter drive are all one and the same thing, that is not to say that they are all the same. Simpler and therefore less expensive versions are generally less capable of wide speed variations, you will still normally get close to a half speed reduction, and speed increases depend on the motor, but my guess is that you would get at least a doubling in speed if you wanted, so your motor will have a range of around 725 to 2880 RPM if you were to choose to use that.
If you were to get a VFD known as a vector drive, they are capable of going right down to 0 RPM, while maintaining high torque levels, not that you would be advised to do that, one of the reasons for not doing it being that you could overheat your motor because the fan will not be providing as much cooling air to control heat buildup, unless you made other provisions, like a separate cooling fan and ducting.
Racing Tadpole and Morrisman both make good points about going the VFD route, but these potential problems may or perhaps may not be an issue for you. I have fitted up a couple of old motors with VFDs, one had the terminations bought out into the terminal box, the other did not. As a retired Rigger/Scaffolder I was able to dig into the windings to bring them out on the motor not originally set up that way, and both motors worked OK with the less sophisticated V/F VFDs (non vector drives). Although not a sparkie, I do have mates and an interstate brother who are qualified sparkies and I was able to run my ideas past them and also get my work checked before the big volts hit it, your experience here may be different.
For you I imagine that it would be useful to have some electronic speed control, not so that you didn't need to use the gearbox, but to make it easier to thread up to a shoulder or to ease parting off pressure or just to have as a way to stop tool chatter.
One other point, you will have heard about changing the motor connection from star (sometimes called Y) to Delta. This is because most VFDs with a 240V single phase input will output 240V, 3 phase output, not 415V 3 phase output which is what most small motors, (3Phase) are set to use in Australia. This is often not a problem because most small 3 phase motors in Australia are connected in Star often signified by a Y on the specification plate, and a motor set up for 415Volts in star, will put out full power if connected to a 240 volt, 3 phase supply when connected in Delta, signified by a ∇ on the specification plate. These are general rules but there are exceptions, so you need to check your motor spec plate to see if your motor is already wired in Y or ∇, but most motors under 5 HP are connected in star while motors 5HP and over are more often connected in Delta∇. If your motor is already connected in Delta, you can still feed it 240Volts 3 phase, but it will only put out half power, probably not too much of a problem in a home workshop situation. BobL will hopefully chime in, he has had good experiences with Powtran VFDs, which are high spec Vector drives for very reasonable prices and if I were in your situation I would seek his advice. In any case good luck with whatever you decide.
Rob
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10th May 2020, 01:02 PM #8Member
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2.2 HP is an odd motor size. Are you sure it is not 2.2 kW ?
This is a very old motor, it is unlikely you would be able to convert it to delta easily. These small, old 3 phase motors are generally
configured in star configuration only.
I would buy a brand new 2.2 kW single phase motor for your lathe. The only issue would be the shaft size (now metric), so
you may have to modify or replace the pulley. Overall it will be simpler, more reliable and less expensive than going with a VFD.
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10th May 2020, 04:40 PM #9New Member
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Thanks for all the replies, especially to Rob, that was a lot of typing and very informative, but as i only paid $400 for the lathe plus a fair amount of petrol moving it, I think I'll go with a new single phase motor.
My turning requirements are fairly simple and the machine has flat belt drive, it's number 18,000.
I had another look at the motor and the plate says:
Compton Parkinson
2HP 1420 RPM
400/440 V 3phase Star
55-4 followed by the serial number (I guess 55/4 is April of 1955)
I had a brief moment of glee when I read in the Similar threads that there was a single phase motor to swap for a 3 phase one---- then I read the date, 2014
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11th May 2020, 08:53 PM #10
Not sure where in NSW you are. Being a bit more specific here can really be a help to you moving forward.
Anyhow if you are anywhere never a motor repairer, a few mins spent there will prob be of great assistance to you. That's what I did when I replaced my lathe motor. Of course when changing from a motor with a metric shaft is one less hassle than dealing with imperial.
Good luck with it. Yeah in your case go along with changing over to a single phase unit.Frisky wife, happy life. Then I woke up. Oh well it was fun while it lasted.From an early age my father taught me to wear welding gloves . "Its not to protect your hands son, its to put out the fire when u set yourself alight".
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12th May 2020, 08:56 PM #11Most Valued Member
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You could use one of these https://www.aliexpress.com/item/4000...archweb201603_
220v single phase input, 380v 3 phase output. They are that cheap that you could also buy one for the coolant pump.
I recently fitted one of these to a mates herbert lathe, a 5 hp motor, it works like charm.
https://www.aliexpress.com/item/3283...27424c4dQHn2FE
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13th May 2020, 12:45 AM #12Diamond Member
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13th May 2020, 10:36 AM #13Member: Blue and white apron brigade
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Thanks for link Shed, tese are really good prices considering they are free shipping as well.
The Powtran equivalents are similarly priced but do not include shipping, which can add up, and ordering is not as straight forward as ordering from a web page. I believe the Powtrans are a step up in quality so for HD continuous use and longevity I would still perhaps consider something more robust .
One thing I that can be restrictive about open design of some of the Ecogo and Powtran models is the exposed terminals which means then need to be put inside an enclosure of some kind. Enclosing VFDs is not that big a deal especially if there is a machine cabinet space handy, but then I worry about overheating so a bit more work is required eg adding an enclosure fan.
This shows the two PI130 Powtran VFDs I'm using n my mill.
These VFDs are what I would call semi enclosed
tuckedawayVFDs.jpg
Then there is the thought that it's not a bad idea to put even fully protected VFDs inside an enclosure anyway to keep the metal dust and grit out of them. I know most people don't worry about this but I reckon this would shorten their lives eventually.
The VFD on my DP is near my welding bay and even though I have extraction on the welding bay some fumes still escape.
This SAJ VFD has since been replaced by another Powtran
complete.jpg
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13th May 2020, 09:34 PM #14New Member
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Thanks for that Shed but the Ali Express site came up with no shipping to Australia when I got into it.
However I did find this on E-Bay:
https://www.ebay.com.au/itm/1-5KW-2H...5.c10#viTabs_0 at $104 with free postage
and I got a chance at a 2.5 hp 240 volt 13 amp motor (used) for $118
how would this go with 10amp houshold power?
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13th May 2020, 10:01 PM #15Most Valued Member
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