Puppeteer

Author Topic: Lister VA gen head  (Read 6364 times)

potter

  • Full Member
  • ***
  • Posts: 110
    • View Profile
Lister VA gen head
« on: May 30, 2010, 09:14:52 PM »
I am in the process of rebuilding a Lister VA, I am having to replace all of the wires in the gen head but i am having a problem in figuring out what the small wire wound variable resistor is for or how it should be wired . The large one I think is the shunt field regulator but I cannot see in any of the diagrams that I can find what the small one is any one familiar with one of these.

       Thanks Potter

Bottleveg

  • Full Member
  • ***
  • Posts: 246
    • View Profile
Re: Lister VA gen head
« Reply #1 on: May 30, 2010, 11:24:21 PM »
Ah, it’s you!
I’ve just replied to your Q on CSOG. I guess you’ve already seen the diagram?
No good? If you give me more detail and maybe a pic I can trace the wire on mine or, I have the diagram in the control box of my VA, but I doubt it’s any different from the 4.5. Let me know, I’ll gladly help if I can.
                                        Mark.

Bottleveg

  • Full Member
  • ***
  • Posts: 246
    • View Profile
Re: Lister VA gen head
« Reply #2 on: May 30, 2010, 11:40:34 PM »
I was just looking at your last pic on Co-Gen. Is that the resister at the top?
The bridge rectifier on the right has been added and something else removed. Could this be why the wires are missing on the resister? Just a thought.

Chris R

  • Jr. Member
  • **
  • Posts: 54
    • View Profile
Re: Lister VA gen head
« Reply #3 on: May 30, 2010, 11:52:35 PM »
Potter,
It's been a long time since I worked on one of those. The following is very general. The small wires are probably for the charging circuit. I think they are part of the of the DC side of the generator. There is probably a switch for high charge and low charge. I think your generator is what I call the small boy as apposed to Fat Boy.

On the small boy there is a transformer type "thing" that is located in the generator housing.The load runs through the transformer and the secondary "small wires" go to an old fashoned sandwich type rectifier and back to the field to increase the field as the load increases one of the adjustable resistors is in series in this circuit, I think. There are some big adjustable resistors to adjust the charging voltage, the no load voltage and the loaded voltage.   The big resistors are in the control box and I think there may be a smaller resistor in the gen housing. If there, that one I think is for adjusting the no load voltage. Some where I may have a schematic? But where?

Clear as mud hey!

Use the above onl as a guide.




Bill Johnson or John Heddon probably know how the thing works. I may have some of those resistors and may be some old brushes. I will check my junk box.  Your resistors may not be any good if all corroded. Rewinding is very possible if you can find out what wire to use.

Good luck.

Chris

potter

  • Full Member
  • ***
  • Posts: 110
    • View Profile
Re: Lister VA gen head
« Reply #4 on: May 31, 2010, 12:17:37 AM »
Chris it has me baffled as it is its hooked in parallel with the bridge rectifier which to me makes no sense unless its to keep a constant load on the currant transformer which supplies the ac to the bridge.

potter

  • Full Member
  • ***
  • Posts: 110
    • View Profile
Re: Lister VA gen head
« Reply #5 on: May 31, 2010, 12:29:20 AM »
Bottleveg yes the bridge is replacing a selenium rectifier but the resister is original I guess I am wondering if whoever replaced it got the wiring right I don't want to let the magic smoke out over silliness.All of the diagrams that I have seen don't seem to show this in the circuit
« Last Edit: May 31, 2010, 12:50:21 AM by potter »

Bottleveg

  • Full Member
  • ***
  • Posts: 246
    • View Profile
Re: Lister VA gen head
« Reply #6 on: May 31, 2010, 10:59:06 AM »
Hello Potter, I’ve posted some pics from mine that may help. It only has one resister, a selenium rectifier and transformer in there. Maybe your second resister is an add on? My 8/1 only has a very small rectifier in the genny but has two large ones in the top box.


« Last Edit: May 31, 2010, 11:07:59 AM by Bottleveg »

Chris R

  • Jr. Member
  • **
  • Posts: 54
    • View Profile
Re: Lister VA gen head
« Reply #7 on: June 01, 2010, 12:43:00 AM »
Potter,

I don't know. I will try and dig up what I have on the generators. The last time (4 to 5 years ago) I looked the manual it was in poor shape. the pages were falling apart. A combination of age, oil, and what ever. Since i had no use for it, I just left it alone in its folder.  I will be care full and hope fully can salvage something that i usefull.

Give me a couple days.

Chris

Chris R

  • Jr. Member
  • **
  • Posts: 54
    • View Profile
Re: Lister VA gen head
« Reply #8 on: June 01, 2010, 12:49:57 AM »
Bottleveg,

Take plenty pictures of what you have there. You have a real gem. Almost like new. Having a good record of an original VA and the generator side  in just about pristine original condition is worth documenting.
my 2 cents

Chris

Bottleveg

  • Full Member
  • ***
  • Posts: 246
    • View Profile
Re: Lister VA gen head
« Reply #9 on: June 01, 2010, 06:11:31 AM »
Been looking again at the pic on Co-Gen. My guess is that resistor has been added, but I’m not sure why. One way to confirm would be to take the screws out of the fixing bracket and see if the holes have been drilled or punched.
My 4.5kva has a small resistor similar to that, against the louvers, and two large ones in the top box. My 4.25, same year as yours, has one large one in the top box and one in the genny but no small resistor. I think the functions are the same, just different mounting areas over the years. I’m not sure why my 4.25 doesn’t have the small resistor.