# Colchester Round Head,motor Options?



## Kroll (Jul 12, 2015)

Guys I purchase this lathe bout 5yrs ago and finally pulled it out to start a somewhat restoration project.Breaking it down into sections and doing a cleaning then painting but not down to the last bolt.But I really don't know what I have cause I am new to this game,I did find the #'s Mch NoF3 53656 and that this is/was a working lathe. Besides not knowing what I have I also discover that the motor is a two speed 1800/900 rpm 3hp 208 volts,yes 208 now I don't know what to do about this.I just figure that it was 230/460 volt 3phase but dang the 208 has throw me a curve.
What are the options here,how would a person handle the duel rpms and 208 volts?My plan was just to purchase a VFD/VSD but that's was before I found out its two speed and wrong voltage for my setup?


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## Milehimachine (Jul 12, 2015)

Thought about just changing the motor out?


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## Chipper5783 (Jul 13, 2015)

A motor nameplated at 208V will work just fine on 230V.  The dual speed is no problem, that is sorted by your Hi/Lo switch.  I believe there are a couple methods the motor manufacturer's can take.  The obvious approach is that there are 2 sets of windings (one with 4 poles, one with 8 poles).  I understand there is also a consequent pole arrangment.??

It is probably a pretty large motor for being 3 HP?  Does it have any other oddities (such as a mechanical or electrical brake)?  That may be a factor to consider if you do change the motor.

Regardless, don't sweat the 2 speed - it is a pretty good deal.  I have 2 lathes, both have multi-speed 3 phase motors.  My origial machine (had it for 30+ years) has a similar motor to yours - it is fitted with a manual Hi/Lo switch.  My "new to me" smaller lathe (which is 50+ years old) has a 3 speed motor (2/4/6 pole operation) with full load contactors for each speed - change on the fly.

The VFD would probably work just fine - connect to the high speed windings and don't sweat it (230V will work fine).  There would be nothing wrong with keeping the Hi/Lo, just make sure you never switch it while energized - probably would toast the VFD.


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## wa5cab (Jul 13, 2015)

Kroll,

If the motor is marked 208 VAC, it has to be a 3-phase motor, as that has never been a standard single phase voltage anywhere on the planet.  If you actually have 3-phase power to your shop (the guy was still laughing when he hung up on me years ago when I called HL&P (Houston Looting & Pillage) and asked how I would go about getting 3-phase power run to my garage), and if you have 120 VAC nominal on the single phase lines, you do not have 230 V 3-phase anyway.  In a 3-phase Wye wired system (three lines and a hot neutral), you can only have 120/208 RMS.  The only way you could get 230 VAC would be in a single phase system where the line to neutral voltage was 115 VAC RMS.  Then you would have 115/230 VAC single phase.  If you have 230 VAC on a 3-phase wye system, the single phase voltage would be about 132.7 VAC, which would pop light bulbs and ballasts frequently.


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## Kroll (Jul 13, 2015)

Thanks guys for the replys,it is a 3 phase motor which I do have one machine that is 3phase but the voltage is 230/460 input that I hook up for 230volt single phase input with 230volt 3phase output VFD.This motor is original to the lathe Ruthland brand I think and for a 3hp motor its not that heavy.What was throwing me off is that its two speed(6 motor leads),I just did not know how to handle that,but I really don't know what the oddities are(brake??) with this setup.Has a big drum switch with some kind of switch that has an arm on it and a roller.All this is on the back side above the motor on the outside of the cabinet.So what I am also wondering is for the lower rpms 1800/900 do I just dial in 30hz for 900rpms and 60hz for the 1800rpms?I just figure if I purchase a 2speed 3hp motor single phase motor it would cost more than what I paid for the lathe.
Guys giving the info on my lathe can someone tell me alittle about what I have,if it was made in the 50's or 60's and if its a keeper?


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## adam3999 (Aug 9, 2015)

I believe the serial # dates your lathe to 1966.  I have a 1962 round head model with a similar Newman two speed 1800/900rpm motor.  It's a keeper.

The start/stop lever activates a limit switch when turned on/off, and also a mechanical brake (located inside the top belt pulley) when it is pushed down.  The limit switch has 3 leads and is a standard SPDT switch, so 2 of those can be used to turn a VFD on/off.  The 5-position drum switch (rev2, rev1, off, fwd1, fwd2) has 3 input wires, one for each phase, which you can attach to the VFD 3 phase output.  Last you'll need to ground the VFD to the frame and AC input ground (check your manual).  My motor wiring box had a screw for this purpose.  I ground off some paint and used a copper screw-down terminal for grounding.  To repeat Chipper's warning -- if you leave this drum switch in series with the VFD output, don't switch it under power.

Between the VFD, 2 speed motor switch and manual gear changes, you'll have a huge variety of speeds and torque available to you.  Most folks would probably just leave the lathe in high speed, high gear, and control RPM exclusively with the VFD.  You may find a need for gear changes, however  As an example, my VFD occasionally enters safe mode when running my old motor at low RPM during threading.  Higher motor RPM but low spindle speed via the gearbox is an alternative that avoids this issue.

Have fun!


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## Kroll (Aug 10, 2015)

Thank you Adam,you explained it perfectly where I can understand.I did not realize that the drum switch had that many setting,I never gave it a turn other than just playing with it.Today I just finish putting the finish coat on the cabinet,next is to mount the motor and put me some flex on the motor for the electrical.
Adam if I remove the spindle head for painting will it line back up perfectly due to the v ways,or will it need to be lined back up?


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## adam3999 (Aug 10, 2015)

The headstock sits on the V ways but I don't believe taking it off and replacing it will re-align it perfectly.  I recall reading a procedure in one of the old manuals that talks about tightening the bolts that hold the headstock down and then taking a cut on a 6" or so piece of metal extended from the chuck without the use of the steady rest or tailstock.  If you measure the same work piece diameter close to the chuck as well as at the end of the 6" length, you are not cutting a taper and therefore the headstock is aligned with the ways and carriage.  If a difference in diameter is measured, the headstock needs to be bumped one way or another until the taper is eliminated.

So I think the answer is, it depends how adventurous you are, and how much you are willing to precisely measure after re-installation (or deal with some level of inaccuracy).


Sent from my iPhone using Tapatalk


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## f350ca (Aug 10, 2015)

The headstock on a Colchester Student I had was out of alignment. Guess the V ways don't align them perfectly. I used the method Adam referred to, loosened the headstock and tapped it over till I could cut a shaft in the chuck with no taper, then align the tailstock to it.

Greg


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## Kroll (Aug 11, 2015)

Guys I have not remove the headstock but when I was trying to just  figure it out where the 4 bolts are, which two I can get to but the other 2 looks like I have to take apart the QCGB to remove the bolts.Is this not the case,I'm new at this so I just don't know.But I do feel alittle adventurous,thanks guys for the help


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