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Author Topic: Lister HA and Brush RS1B generator  (Read 1345 times)

Adscnc

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Lister HA and Brush RS1B generator
« on: August 15, 2021, 03:37:27 PM »
Hi
I have just acquired a Lister HA 2 cylinder with a Brush RS1B alternator generator.
(3 phase 15 Kva)  it hasnít run for 10 years.
The engine started on the button.
At this stage I didnít know wether it was capable of generating any electricity.
I fired it up and all went well, until after about 90 seconds I could smell that familiar smell of burning electrics so I shut her down.

It appears that the fins have over heated and taken out a cable and melted the connected block. See photos.
Only the 2 right hand front fin sets have over heated.

Some questions:

What are the fins for? Is it the rectifier/ voltage regulator?
Why might they have over heated, a short some where?
I guess it is not worth repairing.

Can I fit a  modern voltage regulator?
Should I consider replacing the whole alternator?
The lister engine runs well, no oil leaks and in great condition, spins a 1500 rpm.

Is this suitable?
https://www.ebay.co.uk/itm/New-15KVA-400V-1500-Rpm-Stamford-UK-Diesel-Generator-Alternator-450-vat-/254634455766?mkcid=16&mkevt=1&_trksid=p2349624.m46890.l49286&mkrid=710-127635-2958-0
I appreciate that there is some engineering required to mount it!

Any thoughts on this would be appreciated.
Thanks

mike90045

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Re: Lister HA and Brush RS1B generator
« Reply #1 on: August 16, 2021, 07:27:34 AM »
Those fined parts are Selenium Rectifiers.   When they die, they release toxic fumes.  Your manual/schematic will give the voltage and amp rating, modern replacement diodes are much smaller

The cable likely was hanging by a just few strands which were overloaded and melted the terminal block. ( IMHO )

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Re: Lister HA and Brush RS1B generator
« Reply #2 on: August 16, 2021, 07:03:33 PM »
Hi All,

I have researched fitting a solid state rectifier and looks very possible. Unfortunately I dont have a manual , the only info i have is what is on the plates.

Can I fit an AVR? if so does this do away we the need for the rectifier?

Thanks

mike90045

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Re: Lister HA and Brush RS1B generator
« Reply #3 on: August 16, 2021, 07:27:36 PM »
What  is the info on the plates ?    300V  5A ?  something like that ?

You still need to rectify to get the DC control voltages to run the DC half.

I don't know anything about retrofitting a AVR to those.

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Re: Lister HA and Brush RS1B generator
« Reply #4 on: August 16, 2021, 07:57:56 PM »
 hi
415/230 volts
20.9 amps

mobile_bob

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Re: Lister HA and Brush RS1B generator
« Reply #5 on: August 17, 2021, 12:19:32 AM »
it looks to me like a transformer controlled generator, the three large coils above
the selenium rectifiers sure make that case to me, however can you provide a picture of the whole back end, to include the rest of those coils?

the 415v also makes me think of 3 phase, i have an stc 12 that is three phase and has 415volt output.

if it is a transformer controlled generator, i don't believe you will be able to use an avr
 and buy the looks of the windings in the picture the enamel is looking to be in pretty questionable condition.

having said all that, transformer controlled generators are pretty interesting animals capable of much heavy motor starting loads that avr controlled generators, often having surge rating 2x that or the rated load for something like 3 seconds or maybe more.  they can be very tough and hard to kill.

you can replace the selenium rectifiers with silicon rectifiers, but the voltage drop is much less for the silicon rectifiers so the field current will be higher.  there probably is some sort of adjustable field resistor (wire wound affair with a screw terminal that you can adjust).

if you can find a manual or other info on the generator head, i would recommend checking out what you have before you opt to scrap it for a replacement head.

fwiw
bob g
otherpower.com, microcogen.info, practicalmachinist.com
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Re: Lister HA and Brush RS1B generator
« Reply #6 on: August 17, 2021, 08:40:21 AM »
Many thanks Bob.
Good news I have found the manual for it online at ďinternal fireĒ
My wiring is exactly as page 4.
I note that you can fine tune the output by choosing different tappings from the transformers.
So my first task is to choose a solid state rectifier and wire that in. I need a bit of help here choosing the right one and working out which connections to use?
I also need to replace the suppression capacitors that run off the slip rings.
You mention that the enamel is not great, what exactly do you mean, what are the consequences?
Iím enjoying the learning curve on this project!
Regards
Alan

oldgoat

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Re: Lister HA and Brush RS1B generator
« Reply #7 on: August 17, 2021, 12:11:27 PM »
You can pick a 3 phase 1000v  50 amp bridge with heatsink from ebay for about $20.00 as I assume the dc goes to the X and X1 terminals.  If not it will be 6 1000v 20 amp diodes again off ebay.

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Re: Lister HA and Brush RS1B generator
« Reply #8 on: August 17, 2021, 12:37:23 PM »
Thanks Oldgoat.
You have confused me a little there.
Youíve listed 2 different items. Do I need both?
Could you explain a little further?
Thanks
Al

mobile_bob

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Re: Lister HA and Brush RS1B generator
« Reply #9 on: August 17, 2021, 02:08:47 PM »
what i was in reference to in relation to the windings enamel, is the insulating coating
that appears to have some cracking and corrosion in the pictures, it might be just an artifact of the photo and not as bad or bad at all as it looks in the photos

in any case, i would carefully inspect those windings, and get a small can of glyptal (sp) or its equivalent and brush some on the windings to help seal them up and secure them if any are loose so they don't grind on one another from normal vibration and short.

i think the stuff is called glyptal, whatever it is, check with a motor rewind shop and they can tell you what to use, for that matter take a small jar with a tight fitting lid and see if they will sell you a small quantity.

you mention finding a manual, do you have a link to it?

many years ago we discussed either here or on the microcogen forum the transformer controlled generators, and at the time i found a link to the ST generators that are transformer controlled, but have never seen or hear of one being imported to north america, at least one that ended up in the hands of a forum member.

if that is what you have, and i suspect it is, i think you will be really happy with it once you get it sorted out.

if it were mine i would try to get it working to determine if the thing wasn't internally damaged in some way, such as shorted stator or rotor, and if it checked out ok, i might well take it all apart and replace the bearings and do a thorough cleaning, and may well also send the stator and rotor out to have them vacuum dipped and baked if it looked like the insulation was showing signs that it might be improved upon.

all in all a really nice generator design.

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

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Re: Lister HA and Brush RS1B generator
« Reply #10 on: August 17, 2021, 04:08:35 PM »
Hi Bob

Here is the link to the manual.

https://drive.google.com/file/d/1BBu5Z5CbzI7XI0-5yLBqb94Zl7q1BJqm/view?usp=sharing

its a good manual and has answered a few of my questions.
my wiring is exactly the same as page 4.
Regards
Al

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Re: Lister HA and Brush RS1B generator
« Reply #11 on: August 17, 2021, 04:18:21 PM »

When adding the bridge rectifier how do work out which wires from the stator are + and - ?

Al

mobile_bob

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Re: Lister HA and Brush RS1B generator
« Reply #12 on: August 17, 2021, 05:36:50 PM »
on page 4

lower part of the schematic shows the rectifier bridge (selenium rectifiers) that you will be replacing, the three phase coming down off the transformers to the rectifier makes no difference so long as you follow the layout as illustrated, no need to worry about which wires go to which set of diodes

the output that goes to the right of the schematic to X and XX and then up to the field will be the rectified DC coming off the rectifier bridge, and again it will make no difference which is which, unless one lead is attached to a ground before it gets to the field, but the schematic does not show that, and i would be surprised if a ground connection was made.

i didn't read to far ahead, but yes this is a transformer controlled generator, and of particular note, the field is fix (it is mounted to the outside of the case) and the armature is where the power is taken off off, via the slip rings.  this design is much like the old winco design typical of what was sold here in the states for decades, and for that matter may still be offered.

taking power off the brushes requires a relatively large set of brushes, but in my experience the design is about as tough as a tank!  they just seem to work and work and work forever.

if you read the voltage adjustment, you will see the part about changing taps on the transformer and also if still out of range changing the transformer air gap.

i think you will be probably having to not only change taps, but likely the air gap as the silicon diodes (rectifier bridge or discrete units)  have a much lower voltage drop than do selenium rectifiers.  so with lower voltage drop you will likely have 20-30 volts higher output than you probably would like?  i assume 230-240vac 50hz for your use?

what is interesting about the design (transformer control) is the field is supplied with a current for normal output (taps) and if you have a heavy load to have to start the transformer have higher current running through them which boosts the output to cover the droop.  set up correctly they work very well and are capable as stated before of starting heavy inductive loads on the order of 2x or more for a few to several seconds.

so if that unit is rated for instance 10kva it probably can provide 20kva for several seconds without breaking a sweat... it will be limited by the power available from the engine.

i think you have  cool unit, well worth working out the problems and getting it back up and running again.

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

mobile_bob

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Re: Lister HA and Brush RS1B generator
« Reply #13 on: August 17, 2021, 05:39:46 PM »
did a little more reading and found that X terminal to the field they call for it being connected to the + (positive) connection of the rectifier bridge output, and XX being the - (negative) connection to the field.

even though it really shouldn't matter, i would follow their dictates

edit
further reading i find that the field should be about 10% of the output under load. this is a nice spec, so for a 230vac output, i guess they are looking for approx 23vdc on the field.... that will give you and idea how far off the field voltage will be with the new rectifiers, i would expect you might see 25-30vdc? 

the manual is actually very good, and has more detail that i have found before for transformer controlled generators, and having the theory of operation illustrates how they work.

bob g
« Last Edit: August 17, 2021, 05:46:24 PM by mobile_bob »
otherpower.com, microcogen.info, practicalmachinist.com
(useful forums), utterpower.com for all sorts of diy info

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Re: Lister HA and Brush RS1B generator
« Reply #14 on: August 17, 2021, 06:24:46 PM »
Thanks Bob
Will digest this and hopefully make some progress.
Iíll update the post as I progress.

Al