Puppeteer

Author Topic: Lister HA and Brush RS1B generator  (Read 1346 times)

Adscnc

  • Newbie
  • *
  • Posts: 36
    • View Profile
Re: Lister HA and Brush RS1B generator
« Reply #15 on: August 17, 2021, 06:40:05 PM »
Hi Bob
Any thoughts on fig3 page 5, using a variable ratio transformer to adjust the voltage?
Al

mobile_bob

  • Administrator
  • Hero Member
  • *****
  • Posts: 2904
    • View Profile
Re: Lister HA and Brush RS1B generator
« Reply #16 on: August 17, 2021, 09:09:12 PM »
i think you can use the variable transformer, but you might find it doesn't provide enough range to get you dialed in to the voltage you are wanting.

whatever the case, i am sure it can be tailored to get to where you want it to be.

just follow the steps outlined in the manual and you will be golden.

bob g
otherpower.com, microcogen.info, practicalmachinist.com
(useful forums), utterpower.com for all sorts of diy info

Adscnc

  • Newbie
  • *
  • Posts: 36
    • View Profile
Re: Lister HA and Brush RS1B generator
« Reply #17 on: August 23, 2021, 10:27:26 AM »
Hi Bob
Have tidied up the wiring and fitted bridge rectifier.
When run i only get 16.35 volts on all 3 phases at the head.
I have flashed the stator field with 24 dc. Done this twice now in accordance with manual.
Engine running at a constant 1570 rpm.
Any pointers as to where the problem may be?

mobile_bob

  • Administrator
  • Hero Member
  • *****
  • Posts: 2904
    • View Profile
Re: Lister HA and Brush RS1B generator
« Reply #18 on: August 23, 2021, 02:23:19 PM »
take a good look at the slip rings, they should be a bright brassy color
if they are dark, chocolate color, or greenish they need to be cleaned

you can use some 400 wet or dry paper, and scrub them up to brighten them
and then turn the paper over and use the slip rings to provide the profile to give the brushes a bit of scrubbing too.

very typical of slip rings that have been sitting around not used to get a bit oxidized and this makes for a great insulator or in your case a pretty good insulator

also check what the voltage is coming off your rectifiers, going to the field coils.

can you measure the voltage at "x" and "xx" while running?

also check all connections, everywhere that you can get to.

another thought would be to check the field coil continuity, removed either "x" or "xx" from its terminal and then check the resistance across the field wires that attach to "x" and "xx", you only need to remove one leg.

i have no idea what the resistance should be, but i would think maybe somewhere from a few 10's of ohms, to maybe a hundred?  what i would not want to see is an open circuit, which would lean toward either a burned out field coil or a broken lead between coils, or lead going from "x" or "xx" to the coils.

the schematic doesn't show anything between the x connections and the fields, so not much to go wrong there, but an open wire, or bad connection, worse an open field coil.

if it turns out to be an open field coil, don't fret too much, it is much easier to replace a field coil than have to rewind the armature.  a field coil a reasonably handy fellow could make with a bit of effort, or remove and take to a rewind shop to have replicated.

with the selenium rectifiers having gone up in smoke, i am concerned that maybe the fields have shorted? 

also final thought, (sorry for the disjointed response)

remove both sets of field wires from "X" and "x" and do the continuity check as described
and also check between each field wire to the case ground, to see if there is any short to ground.

if you don't have a short to ground, that is a good sign, if you have a resistance reading from say ~10-100ohms or so, i think you would be ok.

when you flashed the field with 24 volts, did you get a huge arc, or just a small flash or spark?

now i am rambling

what output voltage do you get when you apply 24volts to the "x" and "xx" connections?
is that when you get the 16.35volts output on all three phases?

the fact you report and even 16.35 to all three phases, leads me to think this is a field problem or an excitation voltage problem, and not an armature problem, which is good in my opinion. not that problems are good, but an armature problem can be expensive to resolve.

does the reported 16.35 volts reading come from checking between each pair of the three phases? 

can you check between the neutral connection and each of the three phases?

also so that i am clear which animal you have, is it the schematic in fig 3 page 5?

i have a few other thoughts, but lets start with these,

bob g
otherpower.com, microcogen.info, practicalmachinist.com
(useful forums), utterpower.com for all sorts of diy info

mobile_bob

  • Administrator
  • Hero Member
  • *****
  • Posts: 2904
    • View Profile
Re: Lister HA and Brush RS1B generator
« Reply #19 on: August 23, 2021, 02:41:08 PM »
sorry for the long response, didn't see the pictures before i posted

it looks like the slip rings are nice and bright, so that should be ok

i also see the field wires connected to your new rectifier bridge, the two blue wires look to be the field wires, so remove one or both to do your continuity checks.

i don't see a voltage adjust transformer, so i would expect that your unit is fig2 instead of fig3?

the fact that you can flash the field tells me that the field windings are not open, that is if you remove the field wires and can flash through the wires and see a spark?  the field coils are generally connected in series, so if you are getting a spark then the coils aren't open.

from the rectifier the field wires don't go up into a control panel and are connected to a switch or a fuse or breaker do they?  do they appear to go directly to the field coils?  the schematic does not show a switch/fuse/breaker, but that doesn't me one or more might have been added later or as some option?  make sure those blue wires go directly to the field coils and not to some other thing that might be an issue.  but then again, if you have continuity, then even if there were other things they would be good.

hard to diagnose by keyboard!  :)

let me go back and put together a check chart, with a list of things to check, maybe the problem will be apparent and jump out at one of us or someone else following the topic.

good luck


bob g
otherpower.com, microcogen.info, practicalmachinist.com
(useful forums), utterpower.com for all sorts of diy info

Adscnc

  • Newbie
  • *
  • Posts: 36
    • View Profile
Re: Lister HA and Brush RS1B generator
« Reply #20 on: August 23, 2021, 05:23:47 PM »
Hi Bob

I had a small flash when the 24v dc was removed from neg leg.

With one leg removed I have 28 ohms and continuity between x and xx

No voltage adjust transformer is fitted, so fig2 is correct.

Only fuses and meters up in the control panel, so not affecting output.

Adscnc

  • Newbie
  • *
  • Posts: 36
    • View Profile
Re: Lister HA and Brush RS1B generator
« Reply #21 on: August 23, 2021, 05:27:46 PM »
Hi Bob
When flashing x and xx should they be disconnected from the rectifier?

mobile_bob

  • Administrator
  • Hero Member
  • *****
  • Posts: 2904
    • View Profile
Re: Lister HA and Brush RS1B generator
« Reply #22 on: August 23, 2021, 05:40:18 PM »
a small flash, so your fields should be good, the 28 ohms seems about right too.

can you check the voltage on the field wires while the generator is running, check to make sure you have voltage there and let me know what it shows.

also check the  voltage between each phase on the rectifier and let me know what you get there. while it is running of course.

bob g
otherpower.com, microcogen.info, practicalmachinist.com
(useful forums), utterpower.com for all sorts of diy info

Adscnc

  • Newbie
  • *
  • Posts: 36
    • View Profile
Re: Lister HA and Brush RS1B generator
« Reply #23 on: August 23, 2021, 05:46:51 PM »
When applying 24dc to x and xx should they still be connected to the rectifier?

Adscnc

  • Newbie
  • *
  • Posts: 36
    • View Profile
Re: Lister HA and Brush RS1B generator
« Reply #24 on: August 23, 2021, 05:50:46 PM »
can you check the voltage on the field wires while the generator is running, check to make sure you have voltage there and let me know what it shows..???

The field wires? Is this between x and xx  and should they still be connected to the rectifier or disconnected?

Adscnc

  • Newbie
  • *
  • Posts: 36
    • View Profile
Re: Lister HA and Brush RS1B generator
« Reply #25 on: August 23, 2021, 06:39:26 PM »
When I disconnect the field wires from the rectifier and apply 24 Vdc  from the battery directly to the rectifier I get 15 volts across each of the 3 phases and 9 volts from the neutral. The engine is running during this test.

Adscnc

  • Newbie
  • *
  • Posts: 36
    • View Profile
Re: Lister HA and Brush RS1B generator
« Reply #26 on: August 23, 2021, 06:44:55 PM »
When I disconnect the field wires from the rectifier, x and xx, run the engine I get 0 vdc from them

mobile_bob

  • Administrator
  • Hero Member
  • *****
  • Posts: 2904
    • View Profile
Re: Lister HA and Brush RS1B generator
« Reply #27 on: August 23, 2021, 07:21:53 PM »
ok let me see if i can clarify my question

with the engine running:

1. with the field wires connected to the rectifier, check the voltage at x and xx, and note the voltage.

2. remove the two field wires from x and xx and apply 24 volts, and then check the 3 phases to see what power output you get, and note the voltage

3. with the two wires removed, and with them connected to 24 volts, check the output on the two x and xx posts of the rectifier, note the voltage.

4. with the two wires removed from x and xx, and connected to 24volt, check the voltage on each of the input posts of the rectifier, note the voltage.

at some point we are going to get to the bottom of the problem, so be patient and we will work through this thing step by step.

i think we have an excitation problem
what i am starting to think is you are not getting excitation to the field off the rectifier, either the rectifier is bad (possible), or the AC coming off the transformers that feed the rectifier is very low or absent (also possible).

so i guess what i am getting at, is we start at the easy point and work our way upstream and along the way something will pop up and rear its ugly head.

been my experience on engine driven generators, it will turn out to be something simple, and easy to fix (9 times out of 10) the other times it turns out to be something more serious (maybe 1 in 10).  so i think your odds are fair it will be something simple, the only issue that makes me think otherwise is "why" did the original selenium rectifier shoot craps, and yes i am aware that they can die of old age or moisture ingress. i don't think it was a short, else you would have a larger spark when trying to flash the field and the 28ohms seems about right for a field.

i have to leave to take mom on errands and won't be back till this evening (kansas time), meanwhile see what you can check from the listed items, and i will think about a methodical approach to diagnosing the problem.

some of the steps to diagnose come automatically to me, if i had the unit here in front of me, i spent the majority of my career working by myself, so i never had to explain things to others when it came to diagnosis... it is something you just do, while computing what to do next. 

we will get there!

bob g

otherpower.com, microcogen.info, practicalmachinist.com
(useful forums), utterpower.com for all sorts of diy info

Adscnc

  • Newbie
  • *
  • Posts: 36
    • View Profile
Re: Lister HA and Brush RS1B generator
« Reply #28 on: August 23, 2021, 07:28:51 PM »
Bob you are fantastic, many thanks for taking the time to help me, it is truly appreciated.
By the way I am near Birmingham in the midlands in the UK.
I will respond later this evening.
Al.

Adscnc

  • Newbie
  • *
  • Posts: 36
    • View Profile
Re: Lister HA and Brush RS1B generator
« Reply #29 on: August 23, 2021, 09:01:34 PM »
hi Bob

with the engine running:

1. with the field wires connected to the rectifier, check the voltage at x and xx, and note the voltage.

4.5mv dc

2. remove the two field wires from x and xx and apply 24 volts, and then check the 3 phases to see what power output you get, and note the voltage

15.7 v ac on 3 phases

3. with the two wires removed, and with them connected to 24 volts, check the output on the two x and xx posts of the rectifier, note the voltage.

177 v dc

4. with the two wires removed from x and xx, and connected to 24volt, check the voltage on each of the input posts of the rectifier, note the voltage.

287.7 v ac across 3 phases.

Hopefully some good data there?
Al