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Converting Colchester Triumph 2000 Lathe to Single Phase

blueacre

Plastic
Joined
Mar 24, 2017
I am considering purchasing a Colchester Triumph 2000 Lathe. It has a GEC Machine Motor made in the UK. It is 5.5kw (approx 7.5hp) 3 phase, 50HZ, 1395 RPM, Voltage 220-250 / 380-440 V, Delta / Y Connection. I have attached a photo of the motor nameplate. I had to remove it from the motor to get a good picture of it.

I only have 220 Volt Single phase 60Hz power so I am considering the following options to power it.

1. Replace the existing motor with a single phase motor either 1450 RPM or 1750 RPM with a smaller motor pulley to match the RPM at the lathe. I don't plan to do a lot of heavy work with the lathe so I was thinking I could probably get away with a 5 hp motor ?

2. Use the existing motor with a VFD with 220V single phase input and 220 Volt 3 phase output. If I go this route will it work OK with the existing 50Hz motor. arrangement

The VFD will probably cost less than a 5 or 7.5hp single phase motor unless I find a used one at a good price but I have no experience with a VFD installation. I would appreciate suggestions from anyone who has experience with a conversion like this.
 

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I’d go with option 3, which is a (RPC) rotary phase converter. This is the route I took last year to power my 15x50 which has the same 5.5kw motor.

Murf
 
I have the same lathe running on single phase. They are nice lathes. Originally I just swapped to a 5hp single phase. You do get some vibration from the single phase motor but I used some rubber bumpers on the motor mounting plate and got it pretty good. 5HP is tons of power for lathe this size. I ran the machine for several years like this and it worked well.

Most people advise against single phase motors because frequent starts are bad, and you cant get instant reverse. But this machine has forward/reverse clutches and motor runs continuously so everything works perfectly single phase motor.

A VFD will also work. VFDs need to be de-rated when running single phase. Usually recommend 2:1 but Im using a 10HP hitachi vfd now on the origional motor and its fine. A big advantage of VFD is being able to vary the speed but this machine has a belt driven oil pump. You still need oil so I would definitely limit how much slower/faster you go.

A rotary converter will work too of course.
 
As mentioned, RPC would be plug and play, but higher cost if purchasing a turnkey system, although you can buy a a 15Hp phase converter panel for around $200 and then find an idler motor. There is some additional costs in wire, fusing, etc. and the noise. VFD you would need to go with a 15 Hp 3 phase input model and run it in derated mode for single phase input power. They are quiet and take very little idle power. So something like the Hitachi WJ200-110LF, Fuji FRN0047C2S-2U, they are not a direct power source to the machine and should be in an enclosure if Nema 1 with a disconnect switch. Derating of VFD's for single phase input varies by model/manufacturer. There is some programming and you need to switch on/off the motor via the low voltage VFD inputs. This can be done via 2 wire control (sustained switch) or 3 wire control (momentary buttons). You can run the motor via the VFD at 50 Hz and 230VAC as the base speed. Since there is a mechanical oil pump you would want to limit the speed range with the VFD speed adjustment range. You may also look locally for a 5Hp 3 phase motor or check online auction sources. You can often find a new motor for a few hundred dollars or less, and this also gives you more options as to smaller leass costly power sources. There is also the Phase Perfect Simple series which are priced close to cost of a turnkey RPC.
 
I have a Colchester 21x80 lathe running off a Fuji VFD.
Wire the VFD to your single phase panel through a disconnect.
Use the existing switches on the headstock to switch the low-voltage circuit on the VFD. Wire the VFD 3-phase output directly to the motor.
Note of caution; my lathe was originally wired for 440 volt supply, so all wiring in the panel and to the motor was sized fro the lower amps at 440 volts. Be sure to use sufficient gauge wire for 220 volts.
I used a Fuji VFD less powerful than the ideal one for this lathe, so I need to watch the current draw when pushing heavy cuts so as not to overload VFD. Not really a problem.
Once set up, the VFD is basically "invisible" in the operation of the lathe, and very easy to install and set-up.
Bob
 
A VFD will happily take in 60Hz and deliver 50Hz, operating everything at design speeds. You could also have variable motor speed if desired.

An RPC is an option. The motor will run 20% faster on 60Hz, but because you are not boosting the voltage, will deliver 20% less torque. Pulley changes can correct this if you want.

If you can get away with only a small portion of the original power, using the lathe motor alone, with capacitors to form a static phase converter, is an option. You'll only get about 40% power IIRC.

Whatever option you choose, significant wiring changes are likely to be necessary. Especially if it's still wired for UK-style 400V supply with contactors and overloads sized for that.
 
I have the same lathe running on single phase. They are nice lathes. Originally I just swapped to a 5hp single phase. You do get some vibration from the single phase motor but I used some rubber bumpers on the motor mounting plate and got it pretty good. 5HP is tons of power for lathe this size. I ran the machine for several years like this and it worked well.

Most people advise against single phase motors because frequent starts are bad, and you cant get instant reverse. But this machine has forward/reverse clutches and motor runs continuously so everything works perfectly single phase motor.

A VFD will also work. VFDs need to be de-rated when running single phase. Usually recommend 2:1 but Im using a 10HP hitachi vfd now on the origional motor and its fine. A big advantage of VFD is being able to vary the speed but this machine has a belt driven oil pump. You still need oil so I would definitely limit how much slower/faster you go.

A rotary converter will work too of course.
Thanks for the info - sounds like 5hp should be fine if I go with a replacement single phase motor. I dont plan to do any heavy turning on large parts. If I go VFD you mentioned a 10HP unit - are you using the 10HP VFD with the original motor - is the original motor on yours a 5.5kw (7.5HP) motor the same as the one I'm looking at?

Re your comment on the oil pump - when I looked at the lathe I saw that there is a pump running off a separate belt from the motor pulley (see picture). I didnt look too close but I assumed that was a coolant pump. Is that the oil pump or is the oil pump internal and driven off the head stock input shaft on the Triumph lathe ?
 

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Thanks for the info - sounds like 5hp should be fine if I go with a replacement single phase motor. I dont plan to do any heavy turning on large parts. If I go VFD you mentioned a 10HP unit - are you using the 10HP VFD with the original motor - is the original motor on yours a 5.5kw (7.5HP) motor the same as the one I'm looking at?

Re your comment on the oil pump - when I looked at the lathe I saw that there is a pump running off a separate belt from the motor pulley (see picture). I didnt look too close but I assumed that was a coolant pump. Is that the oil pump or is the oil pump internal and driven off the head stock input shaft on the Triumph lathe ?
Yes im using a 10hp hitachi VFD with the original motor. Probably the same as yours. Its definitely 7.5hp. A bigger vfd would be safer bet but i got this cheap and its working fine.

Yes that pump is an oil pump for lubricating the headstock gears/spindle bearings. The machine uses a tank of oil down below (you can see it in your picture) and pumps oil up for the headstock. Theres a sight glass up top, you can see if oil is flowing or not. Bit of a weird setup but seems to work fine.
 
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Yes im using a 10hp hitachi VFD with the original motor. Probably the same as yours. Its definitely 7.5hp. A bigger vfd would be safer bet but i got this cheap and its working fine.

Yes that pump is an oil pump for lubricating the headstock gears/spindle bearings. The machine uses a tank of oil down below (you can see it in your picture) and pumps oil up for the headstock. Theres a sight glass up top, you can see if oil is flowing or not. Bit of a weird setup but seems to work fine.
Thanks for the additional info. You and someone else mentioned to be cautious with a VFD that the speed isn't too slow because of the oil pump. If there is room I suppose the oil pump could be driven with a small 120 or 240 volt single phase motor and then there would not be a problem running the main motor at slower speeds with the VFD. Just have to be sure the oil pump motor is running before running the main motor.
 
If there is room I suppose the oil pump could be driven with a small 120 or 240 volt single phase motor and then there would not be a problem running the main motor at slower speeds with the VFD.

Unfortunately there is no room for an extra motor. I looked into other options for an oil pump and didnt find anything real easy. I really wanted to have variable speed on this lathe for a few years and couldnt find an easy way to do it. Another issue with this machine is the gears are kind of noisy. Heres what I ended up doing to fix both these issues. See pic below. Original motor mounted to the back directly driving spindle with 10 rib alternator belt on custom made pulleys.

I actually left the 5hp single phase motor in there to drive the oil pump LOL. It was in there ready to go anyway, and i have the option to hook up origional belts and run the gear head for toque if ever needed. I dont reccomend this, it was a ton of work. But the lathe is amazing to use now, was worth it for me. Exactly how I want it now.
 

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I recently helped a bloke put a KB Electronics VFD on a 2 speed 3-ph 7.5 HP lathe motor. The lathe had a two speed rotary switch and we wired this to the VFD to basically do a speed select. Fed from a 230V single phase dryer plug.

It worked fantastic and he has the added bonus of using the original rotary switch to control the lathe so that it works just like the original controls.

The drive documentation was top notch, reputable manufacturer, and inexpensive. What’s not to like?
 
I am considering purchasing a Colchester Triumph 2000 Lathe. It has a GEC Machine Motor made in the UK. It is 5.5kw (approx 7.5hp) 3 phase, 50HZ, 1395 RPM, Voltage 220-250 / 380-440 V, Delta / Y Connection. I have attached a photo of the motor nameplate. I had to remove it from the motor to get a good picture of it.

I only have 220 Volt Single phase 60Hz power so I am considering the following options to power it.

1. Replace the existing motor with a single phase motor either 1450 RPM or 1750 RPM with a smaller motor pulley to match the RPM at the lathe. I don't plan to do a lot of heavy work with the lathe so I was thinking I could probably get away with a 5 hp motor ?

2. Use the existing motor with a VFD with 220V single phase input and 220 Volt 3 phase output. If I go this route will it work OK with the existing 50Hz motor. arrangement

The VFD will probably cost less than a 5 or 7.5hp single phase motor unless I find a used one at a good price but I have no experience with a VFD installation. I would appreciate suggestions from anyone who has experience with a conversion like this.
I have about the same issue you were going thru. I got a Mori seiki Ms 1250 7.5 hp 5.5 kw. The rotary phase motor I have is 7.5 hp. It starts lath motor fine, until you ttlrying to start with belts on to head. Then pulling 100Amps. Voltage at phase motor hot leg 190 v drops to 24v. So not enough power to start machine. I’ve been told different things. Put a VFD and you’re fine. Cheapest fix. Or got to go to 15 hp rotary phase converter. Or I go to single phase 5 hp or whatever fits where 7.5 is. Any offer to what you did and how it works? I’m not electrically smart. So simple terms and any advice sure appreciated!!
 
I have about the same issue you were going thru. I got a Mori seiki Ms 1250 7.5 hp 5.5 kw. The rotary phase motor I have is 7.5 hp. It starts lath motor fine, until you ttlrying to start with belts on to head. Then pulling 100Amps. Voltage at phase motor hot leg 190 v drops to 24v. So not enough power to start machine. I’ve been told different things. Put a VFD and you’re fine. Cheapest fix. Or got to go to 15 hp rotary phase converter. Or I go to single phase 5 hp or whatever fits where 7.5 is. Any offer to what you did and how it works? I’m not electrically smart. So simple terms and any advice sure appreciated!!
I am no expert on this subject the following is info I have gathered from forums and other online sources that might answer some of your questions.
  1. I believe with a rotary phase converter the idler motor needs to be larger than the motor you are trying to start - that could be from 1.5 times up to 2 or 3 times larger depending on the type of equipment yo want to start. A fan would need a smaller idler motor because the rotating load is relatively small and easier to start. A lathe with no clutch and a large chuck is much harder to start to get the heavy rotating load up to speed. A lathe with a clutch is easier to start because you are only starting the motor and once its up to speed you can engage the clutch.
  2. With a VFD it is still recommended to oversize the unit, i.e. use a 7.5kw 10HP VFD to start a 5 HP motor. However with a VFD you can program it to accelerate slowly over several seconds which reduces the starting current and may allow you to get by with a smaller VFD. I ended up buying a 5HP lathe. I am going with the VFD on my lathe. haven't done the conversion yet but I found a used 5HP 3 phase 240 volt motor to replace the original 5 HP 575 volt 3 phase motor for $70 and the 7.5kw 10HP Vevor VFD was $230.
  3. Years ago I bought a large old lathe with a 10HP 3 phase motor. That time I went with a 5HP single phase motor. I reduced the pully size on the motor by approx 1/3 the diameter to reduce the top speed and draw less HP. I also have no need to turn large parts with heavy cuts so I have never had a problem with the 5HP motor. VFD's were not as cheap then and I got a used single phase motor at a reasonable price. I think these days you could get a used 3 phase motor and new VFD for less than a single phase motor.
Have a look at some of the earlier replies to this post - there is goof info from other people regarding motor and VFD sizing.

Hope that helps
 
I am no expert on this subject the following is info I have gathered from forums and other online sources that might answer some of your questions.
  1. I believe with a rotary phase converter the idler motor needs to be larger than the motor you are trying to start - that could be from 1.5 times up to 2 or 3 times larger depending on the type of equipment yo want to start. A fan would need a smaller idler motor because the rotating load is relatively small and easier to start. A lathe with no clutch and a large chuck is much harder to start to get the heavy rotating load up to speed. A lathe with a clutch is easier to start because you are only starting the motor and once its up to speed you can engage the clutch.
  2. With a VFD it is still recommended to oversize the unit, i.e. use a 7.5kw 10HP VFD to start a 5 HP motor. However with a VFD you can program it to accelerate slowly over several seconds which reduces the starting current and may allow you to get by with a smaller VFD. I ended up buying a 5HP lathe. I am going with the VFD on my lathe. haven't done the conversion yet but I found a used 5HP 3 phase 240 volt motor to replace the original 5 HP 575 volt 3 phase motor for $70 and the 7.5kw 10HP Vevor VFD was $230.
  3. Years ago I bought a large old lathe with a 10HP 3 phase motor. That time I went with a 5HP single phase motor. I reduced the pully size on the motor by approx 1/3 the diameter to reduce the top speed and draw less HP. I also have no need to turn large parts with heavy cuts so I have never had a problem with the 5HP motor. VFD's were not as cheap then and I got a used single phase motor at a reasonable price. I think these days you could get a used 3 phase motor and new VFD for less than a single phase motor.
Have a look at some of the earlier replies to this post - there is goof info from other people regarding motor and VFD sizing.

Hope that helps
Ok I don’t know much about VFD, at all. His starter motor is 7.5 hp, the shaft of that motor is hooked inline to alternator/generator? There’s not a VFD wiring out of it runs to breaker box, the other 2 leads is from his main breaker box. So 125v 125v and hot leg 190v coming off those 2 motors. Both motors come on, then he flips a switch to turn off the 7.5hp motor, then just one motor is on . What’s that called? And can that old of a motor on my lathe work with VFD? I heard it’s a 60 hertz signal and the lathe a 50 maybe? Someone said my motor on lathe wouldn’t be VFD compatible. I’m just lost! Lol. I think he wants to buy a single phase 5 hp and put on it. I thought simplest would be to take off his 7.5 starter motor and put a 15 hp there. But I don’t know
 
I am considering purchasing a Colchester Triumph 2000 Lathe. It has a GEC Machine Motor made in the UK. It is 5.5kw (approx 7.5hp) 3 phase, 50HZ, 1395 RPM, Voltage 220-250 / 380-440 V, Delta / Y Connection. I have attached a photo of the motor nameplate. I had to remove it from the motor to get a good picture of it.

I only have 220 Volt Single phase 60Hz power so I am considering the following options to power it.

1. Replace the existing motor with a single phase motor either 1450 RPM or 1750 RPM with a smaller motor pulley to match the RPM at the lathe. I don't plan to do a lot of heavy work with the lathe so I was thinking I could probably get away with a 5 hp motor ?

2. Use the existing motor with a VFD with 220V single phase input and 220 Volt 3 phase output. If I go this route will it work OK with the existing 50Hz motor. arrangement

The VFD will probably cost less than a 5 or 7.5hp single phase motor unless I find a used one at a good price but I have no experience with a VFD installation. I would appreciate suggestions from anyone who has experience with a conversion like this.
I go along with Murf. I am rebuilding a Triumph 2000 and I also have a Holbrook 13 x 30 which I used today. The Holbrook has a 3 HP 3 phase motor. I took my 5 Hp , 3 phase motor off my (No longer needed) compressor and built a 110 volt pony motor with a scateboard wheel on the shaft. My 110 motor pushed against the pulley on the 3 phase with 220 single phase running to the 3 phase motor. once you get the 3 phase turning, flip the switch suppling 220 single phase and it will supply 3 phase to the lathe.
 
I am considering purchasing a Colchester Triumph 2000 Lathe. It has a GEC Machine Motor made in the UK. It is 5.5kw (approx 7.5hp) 3 phase, 50HZ, 1395 RPM, Voltage 220-250 / 380-440 V, Delta / Y Connection. I have attached a photo of the motor nameplate. I had to remove it from the motor to get a good picture of it.

I only have 220 Volt Single phase 60Hz power so I am considering the following options to power it.

1. Replace the existing motor with a single phase motor either 1450 RPM or 1750 RPM with a smaller motor pulley to match the RPM at the lathe. I don't plan to do a lot of heavy work with the lathe so I was thinking I could probably get away with a 5 hp motor ?

2. Use the existing motor with a VFD with 220V single phase input and 220 Volt 3 phase output. If I go this route will it work OK with the existing 50Hz motor. arrangement

The VFD will probably cost less than a 5 or 7.5hp single phase motor unless I find a used one at a good price but I have no experience with a VFD installation. I would appreciate suggestions from anyone who has experience with a conversion like this.
Hi
My case is different.
I have purchased a Colchester Mascot 1600, 80 inch Gap Bed Lathe make 1976. 12.5 HP motor, 0.5 HP coolant pump, 3 phase , 220-440V, 50 Hz.

I have 3 phase power in my machine shop, 220V-440V, 50 Hz and want to use 3 phase for the lathe, rather than using 1 phase which most are suggesting in hobby shop / house shops.

Is there a method that a VFD can be installed on this lathe. 16 speed gear box, 40 RPM-1600 RPM
 

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220/440 three phase is not a thing; you likely have 220/380, 230/400, or 240/415. They're effectively interchangeable. The phase-to-phase voltage in a three phase system is 1.73x (sqrt3) the phase-to-neutral voltage, not double.

You should be able to install a suitable 15HP VFD in place of the main motor contactors. It would not need to be derated for single phase operation.

The brochure lists the motor as 7.5HP, not 12.5HP. Has it been upgraded?
 
Greetings! Thank you for your prompt reply.

You are correct. The Colchester Lathe Company provided Operation and Maintenance Manual for my Colchester Mascot 1600 (make 1976) machine No. 7/006/10995.

It has a 10 HP 3 phase motor 415 V, 3 Ph, 3 wire, 50 Hz' wiring diagram
Direct On Line (DOL) standard control circuit phase to Phase
It has 0.5 HP coolant pump motor
Therefore 10.5 HP ( 7.72 KW) motor.

The newer machines from company have Vector Drives and VFD mounted on them.

1. Can I still use this 10.5 HP
220/440 three phase is not a thing; you likely have 220/380, 230/400, or 240/415. They're effectively interchangeable. The phase-to-phase voltage in a three phase system is 1.73x (sqrt3) the phase-to-neutral voltage, not double.

You should be able to install a suitable 15HP VFD in place of the main motor contactors. It would not need to be derated for single phase operation.

The brochure lists the motor as 7.5HP, not 12.5HP. Has it been upgraded?
 

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Greetings!. Thank you for your prompt reply.
I have attached the electrical motor plate and wiring diagram from the Original Machine Manual.
Colchester Mascot 1600, 80inch Gap Bed
10 HP Motor + 0.5 HP coolant pump motor = 10.5 HP total ( 7.72 KW)

Mostly people having 3 phase input are converting the lathe to single phase input and putting a VFD to suit their lathe machine. I want to use ALL three input phases, with the thinking I want to cut/ heavy cut stainless steel, nickel and cobalt base super alloys and Titanium alloys. Therefore, need the torque and flexibility of low variable speed to meet cutting parameters of particular metallurgy/alloy part....

Q1 If this is doable What will be the VFD specifications?
Q2 I still want to have the pulley and belts on the machine.
Q3 Many new machines of Colchester have Special Motors to suit VFD- vector controlled drives. Conventional motors 3 phase, 50 Hz, are likely to get heated up when run at slow RPM..and may be required far more forced cooling...is some are suggesting
Q 4 3 phase input VFD will provide the torque and resilence to heavy depth of cuts...Is the thinking flawed
Q5 We have a CNC turning centre 10" LMW, but it is not suited to take heavy cuts or machine castings successfully. Therefore, the rational to go for large conventional lathe with a DRO on it seems to be correct option; as such large lathe of make Mazak or DNMG Mori Sieke are beyond pocket of small and medium enterprise like us.
Q6 I want to install an oil filter (for gear box having 55 litre ISO 32/ tellus 52 oil) in line. The oil pump (gear type) is mounted on the spindle which is run the lathe motor. At present there no such online oil filtering with the machine. My foreman is suggesting that there is not need for oil filter, as the gear box is closed and oil tank is closed sealed with oil breathers in two locations.
Q7 I am thinking to use the existing 0.5 HP pump with the lathe machine to circulate the coolant/cutting oil FILTRATION system. The filtration system will be a cartridge type or (suggest better) 65 micron in conjunction with a OIL SKIMMER to drive out floating debris, dust, sludge. The reason is I want to use INTERNAL COOLING TOOL HOLDERS for cutting, turning, PARTING and Threading operations; rather than external cooling with directed coolant tubes to the cutting edges of the tool during operation.

Q8 The Coolant Pump pressure would be less than 5 bar at the moment. I intend to raise the coolant pressure (variable) from 5 bar to 30 bar. For this, I am reviewing Grundfos MTS-20 Screw VFD pump which can deliver coolant from 2 bar to 70 bar . Heat Resistant Nickel and Cobalt base alloys are difficult to machine due to notching of cutting edges, and difficulty in driving heat away from the work piece and cutting inserts. This deteriorates cutting edge life, with poor finishes. High Pressure Coolant and drive up quality and productivity of machining- stainless steels, duplex ss, Ni- base, Co- Base and Ti alloys. The machine lacks such provision today.

Since power costs are very high today, compared to the 60-70-80's energy consumption was not an issue earlier.
Using VFD motor drive and VFD coolant pump drive on such large lathe should help in making best use of energy while still maintaining efficiency, product machining quality and keeping costs under control.

I will appreciate forum's advice on the above Q 1 to Q 8 that can help take my thinking forward.

Sincerely
Vishal Kumar [email protected]; www.acmealloys.com M : 0091-98-111-15423
 
1) 10HP, probably heavy duty rated, 3~ in/out, 380-480V class.
2) Sure. It would be stupid to get rid of them.
3) Cooling is only a concern at considerably reduced speeds and where full torque is required for prolonged periods. I don't think it's usually an issue in machine tool applications because the setup time between cuts usually limits your duty cycle anyway.
4) A three phase drive will not increase the motor torque. All it will do is allow you to deliver the same torque at the same or lower speeds. Is the 16-speed gearbox not sufficient? The manual lists 20-1600RPM and 20RPM is... pretty slow. VFDs give you 'intermediate speeds'.
5) Sure, but a conventional lathe with a direct-on-line motor will do that just as well.
6/7/8) No comment.
9) I don't think VFDs have a very significant impact on power draw in machine tool applications, especially when running at higher loads. Usually the operator wage is tens to hundreds of times higher than machine power consumption. 5kW is ~<$1 per hour, and the machine is probably only running a third of that time. You might get, maybe, a 25% reduction in power if you dial the VFD to a lower speed and you're not cutting?

VFD efficiency improvements are often for things like pumps/fans, where half the flow at half the pressure means a quarter the power, but you run for twice as long.

When run at high power and full frequency, VFDs actually add a couple of percent loss: the motor is still receiving 'mains power', but now you have a whole bunch of converter electronics wasting power.
 








 
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