using a static phase converter on a lathe coolant pump

  1. brewdexta

    brewdexta Member

    Messages:
    3,664
    Yorkshire
    I bought a Colchester chipmaster last year and I'm just getting around to mess with the coolant pump which is the original from 1958. There was suds residue in the lathe when I bought it so I think its working.

    I could use a pond pump or buy a single phase pump however I would like to see if I can get this one working first, its built to fit the coolant reservoir etc.

    Here's the label off the pump, the HP and amps are blank but I seem to remember reading it is 0.05HP - I could be wrong.
    [​IMG]

    Using this very informative web site I have scaled down the capacitor sizes from the 1HP values he mentions as per the following diagram
    [​IMG]

    Has anybody done this before, especialy with a small motor, and have any tips, capacitor values etc?

    Cheers
    Andy
     
  2. graffian

    graffian Seer unto the end of his beard

    Messages:
    2,708
    Location:
    gatwick
    Yep.
    I stuck a capacitor from a fluorescent light on the motor on my mills oil pump.
    The oil pump worked perfectly in a short, maybe an hour or so, test. Since then I have run it for several days non stop, runs smooth and doesn't seem to get hot. I think I must have lucked out as I didn't give it any thought, just wacked the capacitor from live to the terminal I couldn't feed.
     
  3. brewdexta

    brewdexta Member

    Messages:
    3,664
    Yorkshire
    interesting :cool:

    They are about 2uF I believe so in the right ball park for a small motor - I think. I've got some knocking about, might be worth trying them as a test.

    Cheers
    Andy
     
  4. madkayaker

    madkayaker Pro sparkey Pro Welder

    Messages:
    13,695
    Cumbria
    i have seen small motors run by using a capacitor between two of the windings. so for example live to L1 Neutral to L2 then a capacitor between two and three.


    especialy as that motor is duel voltage all you need to do is create a shift in the phase wiring which is what the capacitor will do
     
  5. brewdexta

    brewdexta Member

    Messages:
    3,664
    Yorkshire
    Hi Madkayaker
    The diagram I show is supposed to do just that, its a bit more sophisticated but in essence its just creating the extra phase by using a capacitor and also has a starter in case its needed. I think I'll get a few capacitors and have a play in between boughts of Christmas indigestion ;)

    Cheers
    Andy
     
  6. madkayaker

    madkayaker Pro sparkey Pro Welder

    Messages:
    13,695
    Cumbria
    Go for simple first it's only a small motor so should work fine
     
  7. Pete.

    Pete. Member

    Messages:
    8,271
    Location:
    Kent, UK
    I know of someone else who has done exactly this and had it run for years.
     
  8. brewdexta

    brewdexta Member

    Messages:
    3,664
    Yorkshire
    Thanks guys - sounds like the way to go. I'll try the simple way first:D
     
  9. brewdexta

    brewdexta Member

    Messages:
    3,664
    Yorkshire
    I've been a little frustrated that I have days off but can't get into the workshop as much as I want however I have managed to do a few small jobs, firstly the suds pump needed a new cable and it didn't fit the coolant reservoir and the swarf filter had come away so small jobs I can nip out and do when I get chance to sneak out for an hour.

    First swapping the lead, here she is in the vice with the new lead connectors about to be terminated, the lead is a bit thick but its the only 4 core I have at the moment. Note the white porcelain connector hanging over the top slightly to the right. This is where the motor windings are connected in a star configuration. I can always swap any two of these over at either end of the cable if the motor runds backwards

    [​IMG]

    The lead terminates on a switch on the top, the wiring was as follows :-

    Existing wiring on switch from motor
    top black no label
    middle red labelled A2
    bottom blue labelled C2

    Old lead
    top red
    middle blue
    bottom black

    New lead
    top brown
    middle grey
    bottom black

    The 4th wire is the earth.

    The capacitor(s) I'll be using to form the 3rd phase won't fit inside the top of the motor so will stick them in a seperate switch so I don't have to fiddle around the back of the lathe to turn it on.

    You can also see the swarf filter has broken away from its housing so I welded that up, here's it clamped up ready to weld, the filter and the surrounding were different thicknesses but not really stressed so a couple of little tacks was all that was needed.
    [​IMG]

    Finally here's the suds pump in place, when I first got it the lead hit the lathe and it wouldn't fit and just rotating the pump on the plate meant the suction tube fouled the reservoir. At some point the pump has been apart and assembled incorrectly, had to take it apart to get it right. It better not be knackered after I've done all this :rolleyes:
    [​IMG]

    The lathe has got a 3 phase motor, I took out the old 1.5HP lump with kops variator (its ex-Leeds University so lower powered than the industrial version) and put in a 2HP motor that I wired up delta and added a Mitsubishi inverter both from Inverter drive supermarket and added a variable speed control from Tesla. Due to the variable speed control I didn't want to try and reconfigure the suds pump motor to delta and drive it from the inverter.

    Here's the old lump
    [​IMG]

    Here's the new motor in situ. I had to change the motor pulley as a different shaft size so changed the pulley diameter so the lathe top speed was similar to the old motor. The trouble is the motor pulley is bigger than the old one so I should have moved the motor to the back a little rather than keep the same centre line as the old one. I think I have just about got away with it but may move it if it catches with the belt drive for the travel/screwcutting. I currently have this disconnected as I'm trying to fix an oil leak on the screwcutting gearbox, third time lucky.
    [​IMG]

    Here's the lathe with variable control on top near the old on-off switch. I'm currently making some aluminium washers for my dad's Velocette Venom rebuild.
    [​IMG]

    I couldn't find any old fluorescent light capacitors in the workshop, I could take one out of a fitting but means getting the ladders out so will wait for maplins to deliver the ones I've ordered. If it works I'm going to plumb it into the adjacent millling machine and let it drain back into the lathe suds tray. The milling machine hasnt got a proper stand or tray at the moment, that's one of my next projects where the new MIG will come in handy ;)

    Cheers
    Andy
     
  10. Robotstar5

    Robotstar5 Casanunda Staff Member

    Messages:
    17,781
    Location:
    Birmingham
    The first pic appears to be rubber sheathed cable, keep an eye on it as some rubbers can swell when exposed to oil.
     
  11. brewdexta

    brewdexta Member

    Messages:
    3,664
    Yorkshire
    Good spot, it was cable left over from renewing my bore hole pump, I think I'll look around for something a bit smaller with a plastic sheath if it works.....
     
  12. brewdexta

    brewdexta Member

    Messages:
    3,664
    Yorkshire
    Its junk!:(
    had a check of the windings while I had the top off the pump, no continuity. Took the pump apart and the windings are fried. So bought on of these and will adapt the plate to fit it.
    If I had a pond or fish pump I woud have tried them but seeing as I didn't I bought supposedly the real thing, its a bit cheap though so I'l reserve judgement until it arrives.
     
  13. brewdexta

    brewdexta Member

    Messages:
    3,664
    Yorkshire
    I fitted the pump a while ago, works fine but the pump is designed for flow not pressure so I'll need to fit some bigger bore pipes etc. The outlet from the pump was 5/8" but I've used the old pump hose tail fitting which is 3/8" then a step down to 1/4" to feed the flexible hose. I'm also using cutting oil which is more viscous than suds which slows the flow too.

    I have a 1/2" hosetail and I bought some 1/2" flexible coolant pipes on ebay for £5 but the magnetic base stupidly still has a 1/4" fitting so I'll have to drill it out and put a bigger hose tail on that too. Here it is with a 1/4" coolant pipe - only a demo, I don't usually use coolant on brass.

    [​IMG]
    [​IMG]
     
  14. EddyP

    EddyP Member

    Messages:
    320
    UK
    I've got a chip master too, the variator has gone on it now though, so currently looking at doing the same mod you are, direct drive and an inverter.

    What speed motor did you fit and what size pulley on the motor?
    I've got an inverter that can do a 2.2kw motor, hoping that will be enough.
     
  15. brewdexta

    brewdexta Member

    Messages:
    3,664
    Yorkshire
    Hi Eddy
    I'll post some pics, motor details and pulley/belt sizes - probably put it under a chipmaster conversion thread.

    Cheers
    Andy
     
  16. EddyP

    EddyP Member

    Messages:
    320
    UK
    That'll be great, thanks Andy :)
     
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