Haywood Floor Sanders

  1. DeanH Member

    Messages:
    70
    Location:
    West Yorkshire
    One for the electrical boffins such as @brightspark ...

    As mentioned on the today I acquired thread I have bought two Haywood floor sanders that were sold spares/repair on eBay. One blue and one grey.

    The grey one had a broken live/neutral cable between the 13a plug and motor. Snipped it back, rewired the plug and the motor fired up normally. Tested it 10/15 times since, sanded a test patch on the floor, all good.

    The blue one didn't come with a plug attached but had continuity from the end of the cable to the motor. Fitted a new 13a plug and fired it up, fuse blew. Checked the motor plate on the grey one (blue one has been painted over, could be different but casing is identical) and notice the motor is rated at 14a - bugger!

    My questions are:

    1. Could it be an internal fault that's blowing the fuses on the blue one? The grey one seems to be ok?

    2. If not, how can I run the 14a motor on my domestic circuits? Do I need a 16a commando plug? Or can I get a transformer similar to the 110 site boxes?

    Edit: slight brainwave, I have a VFD that I think does single phase to single as well as three phase, could that be of help?
     
  2. fnlvder Forum Supporter

    Messages:
    55
    Location:
    NW cumbria
    It's probably a 110v sander
     
  3. DeanH Member

    Messages:
    70
    Location:
    West Yorkshire
    It's not, motor plate says it's 210-230v, 14A, 2HP, 1400RPM.
     
  4. Agroshield Member

    Messages:
    1,365
    The current draw on motor start is always high. I assume the sanding belt is not connected directly to the motor. Can you temporarily remove anything that would load up the motor at the moment of switching on? That should lower the current draw a little and may be enough to tell you if it is OK or not.

    How long and of what cross sectional area is the cable? A long, skinny cable can lead to voltage drop and current increase. Again, temporarily, try a short length of good 2.5mm2 cable.

    2HP is 1500w, and at approx. 4A per kW, the 14A is maybe a maximum rather than a running current.

    Was it the fuse in the plug blew or the breaker tripped? Breakers have different trip curves and a C or D rating might help if it is the breaker.
     
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  5. DeanH Member

    Messages:
    70
    Location:
    West Yorkshire
    Thanks for the detailed reply, lots to consider.

    The motor has a triple pulley on it. Two belts drive the sanding drum and one drives a dust extraction impeller. I'm starting it with the drum lifted off the floor (there's a lever/mechanism that lifts and drops the drum). It doesn't blow every time, some times it spins up just fine.

    Cable-wise it's a long length approx 10m. Also a good thickness, I would assume 2.5mm2 but I'm hopeless at identifying flex sizes. Including the sheathing the cable is about 10mm diameter.

    Agreed the 14a is probably a maximum.

    Never tripped the breaker, always the 13a fuse at the plug.

    I think I might swap the motors over between machines and see if the fault moves with the motor. If it does then presumably there is either an internal fault, or the motors are different.
     
  6. DeanH Member

    Messages:
    70
    Location:
    West Yorkshire
  7. eLuSiVeMiTe

    eLuSiVeMiTe Member

    Messages:
    12,964
    Location:
    Bedfordshire England
    Bit of copper in the plug...

    I jest though did that with my mill.

    On fast speeds no issue but when I changed the pulleys for slow speed the initial surge would pop the plug fuse Everytime unless I gave the pulley a little spin.
     
    DeanH likes this.
  8. DeanH Member

    Messages:
    70
    Location:
    West Yorkshire
    Don't think I dare do that!! There must be a solution as there's no way houses would have had 16a sockets when the sanders were new (they're big cast iron lumps so not recent!)
     
  9. rtcosic

    rtcosic Member

    Pound Shop fuses? I have a perfectly ordinary Nilfisk power washer. It was regularly blowing the 13A fuse.

    When I finally ran out of my stock of randomly sourced ancient fuses of dubious origin and bought new ones the failure rate dropped radically.

    As it has a nominal 2.7kW motor according to the data plate it does still blow fuses from time to time - especially if the motor stop/starts at very short intervals. Heat soak in the plug/fuse/cable?
     
  10. DeanH Member

    Messages:
    70
    Location:
    West Yorkshire
    The fuses so far have been Bussman, no idea if they're good or not to be honest. If you're managing a 2.7kw motor then surely I should be fine with a measly 1.5kw?
     
  11. Agroshield Member

    Messages:
    1,365
    If one is OK and the other blows the fuse, it must be possible to run them off 13A.

    Do simple things first. Remove the drive belts and spin motor and drum by hand to see how free they are. Try motor under power with no belts.

    Pull the motor and clean and lubricate everything in the drive train. If it is a sander, the wood dust will get everywhere and gum things up. C.f. on upright hoovers, hair wraps round the brushes and the belts slip. Remove hair, good as new.

    The box you linked to will not help you.

    It is possible, I believe, to buy a soft starter for a single phase motor. They are not common and thus they may be expensive.
     
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  12. DeanH Member

    Messages:
    70
    Location:
    West Yorkshire
    A bit more fiddling with a new fuse...

    No belts connected, motor started 10-15 times absolutely fine.

    Drum belts only connected, motor started 5-10 times absolutely fine. Sanded a test patch fine.

    Extractor belt only connected, again absolutely fine 5-10 times

    All three belts together, started fine maybe five times? Sanded a test patch fine, switched it off, switched it on again and the fuse blew.

    The blue one seems to have a lot less resistance in the pulleys despite being the one that blows the fuses.

    Got to nip out now but will do the same tests on the grey one and make sure that one doesn't trip. Might just be coincidence that it hasn't tripped.
     
    eLuSiVeMiTe likes this.
  13. DeanH Member

    Messages:
    70
    Location:
    West Yorkshire
    Done the same tests on the grey one now, hasn't blown a fuse. Bear in mind what I said earlier about the blue sander having less mechanical resistance but blowing fuses, I think the problem is inside the motor.

    When spinning the blue motor pulley backwards there's a rotational clicking that appears to be the brushes. I also noticed what appears to be a centrifugal switch engaging on the grey one, it doesn't seem to do the same on the blue one.

    Would a broken centrifugal switch be a possibility? Could it be leaving the start winding engaged?
     
    Last edited: Sep 9, 2020
  14. Turbo Member

    Messages:
    3,846
    Location:
    Fermanagh, Northern Ireland
    Could also be a capacitor on its way out, can you easily swap them?
     
  15. Agroshield Member

    Messages:
    1,365
    Yes, if it is a split phase motor. If the start winding is energised too long, the motor will get very hot and start to smell. FWIW, I have not seen many broken switches as such, just ones that need cleaning, servicing and adjusting.

    Have you or do you know anyone with a Megger tester? From your description above (blowing fuse on start up after short use but OK from 'cold'), there might be some temperature-related insulation problem. With patience (let it cool down completely before switching back on), you could confirm or eliminate this theory.
     
  16. DeanH Member

    Messages:
    70
    Location:
    West Yorkshire
    There doesn't look to be a capacitor, if there is it's certainly not accessible without stripping the motor down.

    What I am calling a switch here is a bit different to the conventional switches I have seen on YouTube videos of faulty switches (similar to a diesel governer). This is what looks like lots of small weights around the shaft but inside the bit that the brushes make contact with. There's a spring wrapped around them? I'll get a picture up today.
     
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