Lister 2.5K Generator Control

[andypc42]

Hi
I am a new member to this forum.  I was very interested in the post of Potter of the 16 August 2008.  I have a 1958 S-O-M with a 2.5 KVA generator with a N suffix after the unit number.  I have no control boxes just the seven wires coming from the windings and brush sets.  This unit has two sets of brushes for the commutator.  The question I have is, what are the component values for the main field rheostat, auxillary field resistance, current transformer and bridge rectifier.  Would it be possible to obtain  the above?  I have stripped the generator down for overhaul cleaning etc, and it appears to be in good condition except for the slip ring brushes which need replacing.  I am not averse to using modern components and circuit design if I can find a circuit to do the job.
Looking forward to any replies.

andypc42
 

[compig]

Will be interesting to see if this info is available. I have a '53 SOM complete with all control gear in unmolested condition and was going to examine and record details on all the electrical components for future reference in case of failure. Having never seen a SOM instruction manual I don't know if this info is included , there doesn't seem to be a downloadable copy on the web.

[miwyl]

Hi
 I found a schematic for a LS1 s.o.m if that helps.
Some component values listed


http://freespace.virgin.net/stephen.kelly7/pageengines.html


Mike


Jkson 6/1 Voltmaster 5kw 3600 rpm

[AdeV73]

I've found an S-o-M manual on the Internal Fire website. The "downside" is you have to give them a £10 donation in order to access the manuals - but having donated once, you can download any & as many as you like (which is lucky, since I downloaded the 5/1 manual, then the 6/1 manual, then bought a SoM...)

The file in question is called "lstrsom.pdf".

[listeroil]

Andypc

The value of the main field resistor is 15 ohms 4 amps
The value of the auxillary field resistance is 3.5 ohms 2.9 amps
A modern 25 amp 50 volt bridge rectifier will do the job
The current transformer is more of a problem I dont think you will get one of the shelf but perhaps you can make one yourself.
There are 2 types listed for the N type alternator and they are called choke in the specs.
The first one is 86 turns 16swg with tappings at 0. 74. 80. 86.
The second one is Primary winding 48 turns 15swg tapping at 45.   Secondary winding 103 turns tapping at 96 turns.
Both these are listed as suitable for the N type alternator. These are for 230 volt operation. A 50 va transformer could probably be striped down and rewound to do the job.

Mick

[andypc42]

Hi
Many thanks for your replies.
 I apprecaite that you took the time to reply to my post.  Listeroil / Mick thanks for the list of values. I subsequently found the same values on another forum.  The values given for the choke were for a K series Pt No 64-7044
 86T. 2x16 SWG EN Tappings 0,74,80,86.   I have no problem in trying to make the above choke.  Do you know if the 2x16 windings go one on top of the other or are wound together, what kind of former would I use.

Regards
andypc42

[listeroil]

I have just spoken with my mate who is an electronics engineer. He says that the 2 windings are wound together and if they are wound round a core of the same dimensions as the lister core it should perform the same.
I have a 1951 2.5kw SOM in storage and will go over and measure and take a picture of the choke in the next few days if you like.
The other thing he told me was that the bridge rectifier should be rated at 500 volts because it is connected to the AC side of things and it was impossible to tell from the wiring diagram what voltage is going to it. Unfortunatly my 2.5kw SOM is not running at the moment so I cannot take any voltage readings at the bridge rectifier.

Mick

[oliver90owner]

OK, they had all sorts of controllers over the years - kind of evolved/modified as electrics/electronics progressed. I suppose they just shrunk from about 4 boxes to one over the years.

I have a copy of the Lister SOM manual 957/969 printed in 1969. 3 to 4.5 kW

Not sure if I have anything much earlier.

Compig,

You might try Listerdiesel.  He would have them.

Regards, RAB

[andypc42]

Hi listeroil
I think your electronics engineer mate is quite correct regarding the windings.  As to the bridge rectifier I was going to use stud rectifier diodes to and make up the bridge that way.  If you could take some measurements and some photos that would be great.  A bit ckeeky I know but if you would be so kind could you ask your electronics engineer mate for an up to date circuit of the alternator control box.

Regards
andypc42

[listeroil]

Andypc


I thinkthis diagram should be allright for your SOM all the information I got from my genuine 1967 2.5kw SOM manual. All this information applies to the later N type alternators. All of the components should fit in the top box.







The Main field resistor Aux field resistor and Charge resistor are available from http://www.arcol.co.uk/index.php Their PB range are the same as Lister used.  This is a picture of a 12 ohm charge resistor from a 4.5kw SOM here is a picture of a 4.5 top box with charge main and economy resistor fitted on the back face.
.





This is the Economy Resistor they also available from arcol in their PE range



The top box measures 13 inches long 12 inches wide and 7 inches high it is mounted to the alternator with rubber mountings I use these mini exhaust rubbers  1.50gbp each from my local motor factor. It is inportant to fit an earth braid bond from the top box to the alternator frame.



The choke is the same size as a 100va transformer you should be able to get one easy these 2 are very similar to the original one

http://www.maplin.co.uk/free_uk_delivery/100VA_Transformer_Kit_3728/100VA_Transformer_Kit_3728.htm 

http://uk.farnell.com/dagnall-electronics/d3067/transformer-100va-2-x-12v/dp/1166191






Mick

[tiger]

Wow thanks for the schmatics and the Pics I've lurked on this forum for a couple of years and finally have a concept of the Lister SOM! One thing, the rectifier in the picture I believe is of the Selium type, bad, bad, bad, if you are present when it fails! Its smoke is deadly! Put in the new style,silicone ones they are only 1" square and do not kill when they blow. For ratings, double the peak voltage and amperage and install with heatsink compound to the houseing. Your looking at $5.00 to $7.00 US for very cheap insurence.
Thanks again for the pics!

[compig]

Another thanks for the pix and diagrams here.
tiger , in all the years I've been involved in electronics I've never heard that the smoke from a blown selenium rectifier is dangerous to health !!

[andypc42]

Hi listeroil

Many thanks for the pics and information very comprehensive.
For the fuel cut-off electrics and mechanism I was considering a time delay circuit and a currently manufactured solenoid with a built in holding coil. 
All the above is missing off my engine, I just have the exhaust valve lifter.

Once again many thanks for the info.

Regards
andypc42 

[tiger]

Another thanks for the pix and diagrams here.
tiger , in all the years I've been involved in electronics I've never heard that the smoke from a blown selenium rectifier is dangerous to health !!

Compig: In the early 50's I dragged home some power supplies from a plateing shop. My Dad a engineer electromechancal and also a Ham radio operator from the 20's warned me to be careful. I dam near killed the dog, and the cat. When my dad got home one sniff and he knew something had happened, I was white as a sheet shaking,caughing and heaving my guts out.In the late 70's I met a man thru my wifes uncle who worked the gold tailings in california, his ww2 generator quit I metered it out, sent him a silicone replacement but he had found an original and it blew shortly after while testing it. A year later I went to see him, the one I sent was in and working but he was on a oxygen bottle and in a bad way. I havn't seen any military or medical electrical /electroics useing them since the late 60's. That is my 2 cents.

[compig]

Well you learn something every day !!  During my college and University years studying electronics I was never made aware of any danger regarding selenium rectifiers which , in the light of what you have said above , makes me a bit annoyed !!  Certainly in the future I'll be very cautious of the things so thanks for the warning  !!