Saturday, August 19, 2006

Nearly There



No progress last week as I went to Betws-Y-Coed in north Wales for the weekend.
In the meantime, I bought an angle plate and V blocks from ebay - a bit smaller than I wanted with £6 post - but I seem to have been concentrating too much on the Kinglett when it will take too much time, effort and ability that I have.
So spent a couple of hours on the wriring again today, readu to add a mains lead tomorrow. The motor looks out of line for the pulleys, and was difficult to fit with the noew belt, but I think that is because the two pulleys will need realigning when I get it running, hopefully tomorrow.
I gavent sourced a no-volt switch yet and I kind of wish I had kept the steel box I fitted to lathe no 2, and installed the nice forward and reverse switch in it. As is, I will just wire to enable forward for now.

Monday, August 07, 2006

Lathe No 2 Has left the Building

Lathe No2 sold on Ebay for £104 last night, and the guy just came over to collect it just now.
I photocopied the Mk2 littleJohn owners manual, the screwcutting section for him, and also included the excellent Edgar Westbury article on the Kinglett (http://modelenginenews.org/etw/kinglet/page1.html) hosted on Rons excellent www.modelenginenews.org website, which I have taken quite a fancy to.
As I wasn't paying attention he gave me £100 but teh extra £4 would have covered Ebay costs - oh well.

If I were to make the Kinglett, I would have to use solid alloy for instead of the castings, and the skew timing gears look very rpoblematic, so I may redraw this with teh head rotated 90 degrees and the cam in line with teh crank running from spur gears.

Sunday, August 06, 2006

Metropolitan Vickers Motor

I replaced the drive belt on the motor for Lathe number 1 - this was a little annoying as both the backgeared layshaft needed to be loosened off to get the V belt over the pulleys, and also the clevis shaft that controls the pulleys also needed slackening off, and to do this I had to remove the motor.
What made this worse was that I snagged the already loose and dangling motor wires, from the dodgy roller knife switch, and broke one of them. This wasn't a big deal as I was going to rewire anyway, so I pulled it all to pieces to clean up. The Met-Vick motor is a Split-phase or Induction start-induction run motor, with a winding temporarily engaged during starting.
I soldered loop crimps to the bare wires from the windins, but have a little problem. The two windings have different resistances - one is 5 ohms, one is 11 ohms. Obviously, this is DC resistance as Back EMF acts as a voltage source when running to limit current, but I am not sure which is the start winding, switched off by a centrifugal switch, and which is the run winding. According to
http://www.iprocessmart.com/leeson/leeson_singlephase_article.htm
  • The start winding is made with smaller gage wire and fewer turns relative to the main winding to create more resistance, thus putting the start winding's field at a different angle than that of the main winding, and causing the motor to rotate. The main winding, of heavier wire, keeps the motor running the rest of the time

So it looks like the 11ohms winding is the start winding. I also tried to rotate the motor rear bearing plate so the cable entry is vertical, preventing the cable rubbing on the wall. However, the oil feed is then horizontal and will trickle oil everywhere, so not sure yet if this will stay.