250psi Compressor needed

Discussion in 'Parts/Engines Wanted' started by amblejo1, Feb 26, 2019.

  1. amblejo1

    amblejo1 New Member

    The trustees of Thelnetham Windmill in Suffolk are seeking a compressor - preferably a Ruston single cylinder unit for their Ruston 4YHR. If we can’t find a Ruston any belt driven compressor capable of delivering 250psi when driven by a 2HP motor would fit the bill.
  2. TangyeDan

    TangyeDan Active Member

    Keep an eye on ebay, there has been two Ruston starting compressors sold on there recently for less than 100 quid apiece.

  3. amblejo1

    amblejo1 New Member

    Thanks for that suggestion Dan.

    Sadly I was aware of the unit near Doncaster that sold last weekend. I was inhibited by the prospect of a 10 hour round trip to collect it and until this afternoon we were optimistic that a twin cylinder Lacy Hulbert machine donated to the mill last year would do the job. This afternoon, we belted up the LH to a 2HP motor (the most powerful we could afford) and as the receiver pressure approached 6 bar the rpm dropped away and ultimately the motor stalled. We think that the two cylinder compressor is simply trying to press too great a volume per stroke for our motor. Initially I wanted to use a Lister CS to drive the compressor but with space in our small engine house at a premium it was deemed inappropriate. We also have a small Lacy Hulbert which we hooked up to a 1/4HP motor - at about 500 rpm it gave us 220 psi but it took 90 minutes which isn’t very practical when we wish to demonstrate starting our Ruston 4YHR several times each open day. Hence our search for another compressor to recharge the receiver in a reasonable time - preferably a Ruston to match the HR. As an interim measure, we can start the engine on a warm day with 10bar in the receiver from a modern workshop compressor which only takes 15 minutes to recharge from 6-7bar which is what’s left after a start.
  4. Dazzla

    Dazzla Member


    I've got a Ruston compressor that is surplus to requirements. It was new in 1935 and driven by a 2hp Lister D and used to start a large Brush engine so could be what you're after. Location isn't ideal, but I'm sure we could sort something.


  5. Dazzla

    Dazzla Member

    Just a thought - doesn't the engine have a back-charging capability?

  6. picklesquirt

    picklesquirt Member

    Have you tried putting a smaller pulley on your 2 H.P motor ? The compressor may not be as efficient but it should enable the motor to drive it to a higher pressure.
    Good luck
  7. amblejo1

    amblejo1 New Member

    The engine does have a back charge valve but we seem to have a problem with the fuel pump/governor assembly. When we lower the lever to shut off the fuel, a gas bubble appears from the Governor spill valve and we loose pressure in the line to the injector. We can’t recover the pressure to the injector before the engine stops. Additionally we have a small air leak somewhere that is proving elusive to find - if we leave 10bar in the receiver it slowly leaks away over the course of two weeks, so we feel the need for an independent means of recharging the receiver. The windmill volunteers are all geriatrics with me at 66 being the youngster and we all find hand cranking a bit much these days. We were warned by our boiler inspector who certificated the receiver that we shouldn’t leave my workshop compressor on view on open days as we don’t have a ticket for the receiver on that.
  8. amblejo1

    amblejo1 New Member

    We already have the smallest pulley they sell for the motor’s shaft diameter, so we would need a second shaft and suitable pulleys to run the compressor slower.
  9. JohnM

    JohnM Member

    Do you have 3 phase supply?
  10. amblejo1

    amblejo1 New Member

    Thanks for your response John.

    We only have single phase at the windmill.

    The good news is that Darren & Joe Curryer let us buy their Ruston compressor and we are now able to charge our receiver to the maximum pressure our certificate allows with our single phase motor. Yesterday we ran the compressor and started the engine to give it a test run prior to our first public open day on Easter Monday - all was well :)

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