Thanks Thanks:  0
Likes Likes:  0
Needs Pictures Needs Pictures:  0
Picture(s) thanks Picture(s) thanks:  0
Results 1 to 9 of 9
  1. #1
    Join Date
    Mar 2009
    Location
    Melbourne
    Age
    54
    Posts
    825

    Default Finally Finished My 260

    Well I have finally finished restoring my 260 ALTM.

    Every component was stripped down, cleaned and re-assembled.
    I replaced the countershaft bearings, mainly because I buggered one while disassembling it and fitted new drive belts.

    The gear train cover had been bent inwards at some time or other and I was not too sure if I could fix this, it being made of muck metal. Being one of the first things to be removed, I placed it in a press and over the following month or so progressively applied more pressure and finally managed to straighten it out.

    When I first got it I was not too sure how she would come up, but I couldnt be happier with less than 0.01mm runout on the spindle and the bearings are quiet and smooth.

    I kept the 3 phase motor and instaled a Siemens Micromaster VFD which works a treat. This gives me soft start, rapid stop, reverse, jog and of course variable speed from 50% to 200% of rated RPM with constant torque throughout the range.

    I did have to change the windings in the motor from 415 star to 240 delta which was a bit of a pain as the motor is only a three terminal not a six terminal so this meant breaking into the windings to reconfigure them. I have had to do this once before on my Waldon drill press and as long as youre careful not to break any wires or damage the insulation it works fine.

    Cheers,
    Greg.

  2. #2
    BobL is offline Member: Blue and white apron brigade
    Join Date
    Feb 2006
    Location
    Perth
    Posts
    7,182

    Default

    Nice work - and something to aspire to. If I can get 1/4 of the way to where you are I will be happy.

  3. #3
    Join Date
    Apr 2009
    Location
    Boronia Australia
    Posts
    49

    Default

    hi There
    looks great now, so what's the first project for it?
    I am very interested in how you went about the conversion of the motor so wondering if you could post more detail. What make of motor, where have you installed the VFD and where did you procure the Siemens unit etc.

    Currently I am staring at the insides of a Mc Coll junior 3 phase motor as originally fitted by Hercus wondering just how to tackle it so any help would be greatly appreciated.
    Ray

  4. #4
    Join Date
    Mar 2009
    Location
    Melbourne
    Age
    54
    Posts
    825

    Default

    G'day BobL,
    Thanks for that mate, I know what you mean, I seem to have a never ending line of old machines to fix up, Next is an old wood lathe for my wife.

    Ray,
    First job was two of the tools hanging on the back board, I swapped the square head machine screws on the tool post, topslide lock and gear train banjo with hex head cap screws and butchered some old allen keys, much easier than fiddling around with the square head spanner all the time.

    As for the motor, mine was a Hercus fitted 3/4HP Crompton Parkinson three terminal star wound 415V 3 phase motor. I suspect your McColl Jr is probably similar.
    In order to get the rated power performance from 240V 3 phase, they must be re-configured to delta winding.
    With a six terminal motor all winding tails are connected to a terminal and it is simply a matter of re-configuring the links on the terminals to change winding types.
    With a three terminal motor the star configuration is achieved by permanently connecting the tails and winding this in amongst the actual field windings.
    I suspect a three terminal motor was cheaper than a six terminal motor and as these machines were generally manufactured for domestic use quite acceptable.
    The problem for us is that to use these motors with a 240V VFD they need to be re-configured.
    Firstly check the specs plate of the motor, if it says 230/415VAC 3 phase you probably have a six terminal motor, if it says 415 3 phase then you have a three terminal motor. I should point out that there are 415VAC delta wound motors but I doubt you would have one of these on your lathe, if you do then you need a new motor as there is nothing you can do with it short of a re-wind.

    If your motor has six terminals then you’re in luck, just re configure the links for delta.
    If it only has three then it's time to get adventurous. You need to disassemble the motor until all you have is the stator winding, ie, the middle bit of the motor housing with all the windings.
    Working from the rear end where the existing tails hang out, use a sharp knife or scalpel to cut and remove all the binding strings which wrap the windings, depending on how much lacquer has been applied this can be pretty difficult and may call for pliers.
    With the string removed, start carefully (and I mean very carefully) peeling apart the windings, what you are looking for is a bit of insulation tubing with three wires going into it, there are a few with two wires but there should only be one with three, this is the bonding point which forms the centre of the star winding. Be patient and careful not to damage any of the wires or the shellac insulation, if you break a wire here you will have 6 or 7 kilos of scrap iron and copper on your hands.
    Once you have found the commoning point, remove the insulation tube and you should find the three wires joined together. Cut the joint so you have three separate wires then scrape off some of the shellac coating from each (singe it with a lighter for a few seconds then rub with steel wool works good for this).
    You have now separated the three windings and you need to solder new tails to these. Use high temperature silicone insulated wire for this as normal PVC insulation may melt when the motor gets hot, this is not only very dangerous (electricity, zap, death type dangerous) but could cause a fire. Using a multimeter, measure from the existing tails to each of the new tails to identify the three windings and confirm there are no breaks or shorts, a typical reading here is about 9 ohms from memory.
    Now you can tuck all of the windings back, I used cable ties to replace the string to bind the wires neatly. Now all you have to do is re-connect your new and existing tails such that the windings are in delta configuration, re-assemble the motor and hey presto you're done.

    I know this description is long and probably limited in its usefulness but it's hard to describe something like this, I probably should have taken photos as I did it but I was too concerned with just getting the job done. This process took me about two hours and being an electronics technician I am comfortable with working on these sorts of things so allow plenty of time and don't try to rush it..
    The one thing I would stress it that we are talking about potentially lethal voltages here so a lot of care is required. I have access to insulation testers and the like so I am pretty confident my motors are fine but all this needs to be taken into consideration before you decide to have a crack at it yourself.

    I fitted the VFD in the electrical compartment behind the control panel, you can just see the bottom of it at the top left of the second picture above the contactor. I was lucky enough to get my drives as freebies from a mate but. I think Siemens use resellers rather than sell direct, I believe Ramelec is one, try their website www.ramelec.com.au (no affiliation here).

    Sorry about the long post but hopefully it is of some use, I just noticed Ray is in Boronia which is not to far from where I work (Bayswater) so if you decide to tackle this and need a hand feel free to give me a yell.
    Cheers,
    Greg.

  5. #5
    Join Date
    Oct 2004
    Location
    Southern Highlands NSW
    Posts
    1,894

    Default

    On the contrary, Greg. I found your description very good. I also want to convert a 3ph motor to 240V, but having a peek inside it put me off, as it seemed so tricky. You've inspired me to give it a try. Hope I don't stuff it up!
    BTW, any pointers for silicone covered cable? Electrical suppliers?

    Thanks,
    Jordan

  6. #6
    Join Date
    Mar 2009
    Location
    Melbourne
    Age
    54
    Posts
    825

    Default

    G'day All,
    I have had a couple of requests for the wiring diagram of the VFD and control components so here it is.
    This is specific to a Siemens Micromaster 440 6SE6440-2AB15-5AA1.
    Just to cover my bottom, I hope this is helpful but do not recommend anyone use it without getting it checked by a licenced electrician.
    Cheers,
    Greg.

  7. #7
    Join Date
    Mar 2009
    Location
    Melbourne
    Age
    54
    Posts
    825

    Default

    G'day Jordan,
    Thanks mate, the way I saw it I couldnt use the motor as it was so I had nothing to loose and everything to gain.
    Probably try Middy's or Laurance & Hanson, just ask them for hook up wire for use at elevated tempratures, they should be able to help.
    Cheers,
    Greg.

  8. #8
    Join Date
    Mar 2009
    Location
    Melbourne
    Age
    54
    Posts
    825

    Default

    G'day Ray,
    Heres a photo of how the VFD is mounted.
    The VFD has an inbuilt fan and the specs reccomend 100mm clearance at top and bottom, in order to achieve this I had to cut a 100mm diameter hole in the botom of the compartment which will help with ventilation, the white stuff is just a filter medium to stop dust.
    Cheers,
    Greg.

  9. #9
    Join Date
    Apr 2009
    Location
    Boronia Australia
    Posts
    49

    Default

    Thanks for the offer Greg, I will see how I go fortunately I have a spare motor so if I scrap one I get a second chance. As I will have to remove the string etc. I was wondering what is used as an insulating varnish these days? or is it still the Shellac I used many years ago on auto starters and generators.
    I really admire your wiring job very neat and professional. If you would like to see a Craftsman fully rebuilt apart from cabinet and another totally in bits and naked of paint etc. give me a shout

    Ray

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •