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Diana and Jackie

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Posts posted by Diana and Jackie

  1. 11 hours ago, Tony B said:

    An AC current generates a magnetic field across the wire that opposes the flow of current, known as induction. DC does not. Yes any alternating current will flow through Skin Effect, the picture I was told was AC think of a swirling jet of water, it will cling to the sides of the pipe and leave a hole in the middle. DC is a smooth steady flow so can fill all the pipe. Probably better descriptions out there, but it works for me.

    So Tony- given the foregoing, An AC current generates a magnetic field across the wire that opposes the flow of current, known as induction. DC does not.  and expounding your vast knowledge electricity can you explain how a DC clamp meter works?

    Diana

    PS - I did study physics, I think your ideas on electricity are wonderful 🙂 . I am in awe, as I'm sure is Chris McMillan.

    • Like 1
  2. I see.. interesting, a bit like water going down the plughole. the swirling is different depending in which hemisphere you live.

    I must ask the next electrician I see if I can have hollow cables as the inside bit isn't any good and I am paying for it 🙂

    Diana

  3. NOW SOLD

    Owing to having no time and too many things on the go, for sale is a Gas gun firing control circuit. with the two valves, spark plug, and coil.

    I'm also throwing in a spare coil. All this complete with instructions. £55 postage paid. This is unused and untried but the instructions are complete. The circuit is set up for a Browning heavy machine gun, but can easily be adjusted for other gun types.

    You will need to construct the barrel, swirl chamber, fit jets, provide the gas and tubing - all info is with the instructions.

    PM me if interested.

    Please note I will not send the instructions without the parts i.e The complete package needs to be bought.

    Diana

    image.thumb.jpeg.95837d05437777c93dada35035b36fd0.jpeg

  4. You have the wrong type of pipe, it should be copper nickel (Kunifer).

    Kuniper is used for exactly the reason that it does not harden like copper.

    Suggest you replace it with the correct pipe, some rubbers will not tolerate diesel.

    Diana

  5. The thickness is 0.3 mm. who the seller on eBay was I cannot remember. Sorry you'll have to do a bit of groundwork, it was around 6 or 8"" square, more than enough to make a few diaphragms.

    I suspect this will be too thin for fuel pumps as they are under considerable pressure and duty cycle.

    Diana

     

  6. The J60 may or may not have points, some Belgian machines have points. If The J60 has got an electronic ignition module then it will also have a rev limiter built into the module that can be disabled by pulling a fuse which will either be on a fuse holder incorporated into the ignition coil (British Machines) or if a Belgian machine on a fuse holder adjacent to the coil.

    The Rev counter is normally driven by a pickup mounted on the counter through which passes the ignition feed wire. The Rev counter  was made by Smiths Industries and is now unobtainable, through age it loses accuracy and can also lose linearity. because of loss of magnetism and the hairsprings becoming weak, as well as friction through wear in the movement bearings.

    It maybe repairable, in the end I gave up with mine and fitted a VDO rev counter with a sensor off the fan, The VDO rev counter also has a hours run meter.

    The diesel model CVRT uses the same VDO rev counter using a Honeywell sensor mounted on the flywheel sensing the flywheel starter teeth. A suitable sensor pickup point on the petrol engine is also the flywheel starter teeth, were in not for inaccessibility a more ideal sensor pickup point would be the rear of the engine crank toothed belt drive which has less teeth per revolution.

    Anyone doing a conversion to a VDO stepping motor rev counter needs to consider the design of the sensor and it's maximum pulse output, since with too many teeth on the pickup point some sensors cannot cope with the frequency. Some sensors require power and others do not. The other considerations are the clearance between the sensor and the tooth or bolt head it senses as well as the cost of the sensor (The VDO magnetic sensor is astronomical in price) The VDO stepping motor rev counter is the most versatile of rev counters, will cope with most types of sensor and can be calibrated in situ.

    Diana.

     

     

  7. On 3/2/2018 at 10:36 AM, Yeoman said:

    Hi All,

    ref ws19 -I am needing to make up a coax cable to run from the 'A' set aerial socket to the variometer.From 'Wireless for the Warrior' I understand that the coax should be of 80 ohm impedance - I can find 50 ohm easily but not 80 ohm.What coax cable should I use? I understand that the length should be 42" - is this critical or is the length more to do with where the variometer is situated within the ws19 set up?

    Sorry if this sounds a silly question but I am new to military radios so any help/advice that you can give would be much appreciated. Thank you.

    Kevin.

    Television down lead is 75 Ohms and near enough to 80 Ohms that it  can be used and you will see no difference whatsoever at the frequencies used by a WS19

    Diana

  8. I am not a K60 expert - an interesting engine, with opposed pistons and a 2 stroke! I would take some compression readings since you have the injectors out and see what comes from that.

    My experience of 2 strokes is - UGH ! What I do remember though is a worn cylinder hard to start until warm.

    You do of course have the manual ?

    https://www.ebay.co.uk/itm/K60-Rolls-Royce-K60-Workshop-manual-Publication-No-2291/253378490234?hash=item3afe88ef7a:g:PwUAAOxyDLZR-97Y

    As it specifically mentions cold start!

    Diana

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