Author Topic: Some thoughts on building a replica Start-O-Matic control panel  (Read 376 times)


  • Newbie
  • *
  • Posts: 14
    • View Profile
Some thoughts on building a replica Start-O-Matic control panel
« on: November 05, 2019, 09:50:21 AM »
My Lister LD1 SOM did not come with a control panel and I have not been able to source one so far. I am fairly conversant with electronics so I have been toying with the idea of building a working panel from scratch using a mix of old and modern components where necessary. Hopefully, an original will turn up one day.

Has anyone been there and done that?

Here are some of the problems as I see it, and possible workarounds.

1.  Choke (CH) is a prominent part of the panel and plays an important role. This would be hard to replicate as it is unknown what material the toroidal core is made from. (I also note that different part numbers are given for the 12 volt and 24 volt chokes and it would be interesting to find out what the differences were. Maybe wound with different gauge of wire as the 1.5Kw generator outputs a max of about 6 amps whereas the 4.5Kw units puts out about 18 amps of current. Hopefully, someone may be able to explain the differences or take some measurements of wire diameter and toroidal core dimensions of both 12v and 24v chokes). Anyway, I would like to make a replica probably using an insulated core just for show and feed one turn only through a small current transformer and associated electronics to perform the same task as the original choke.

2.  The line contactor (LC) should be reasonably easy to replace with a modern relay with suitable contact rating if someone is able to measure the voltage across it's coil when the generator is operational, or, measure the resistance of the coil itself, please.

3.  Reset switch (K) - fairly easy to replicate it's function with a push button and timer/relay readily available and cheap.

4.  Detection relay (D) should be able to be replaced with any relay with a coil resistance of 100 Ohms.

5.  Meter - I should have something similar that I can modify and rescale.

I have attached the most modern circuit I have for the LD1 and SL1 generators. LD2 and SL2 circuit is very similar except for an extra resistor in the reset switch circuit and some difference in the wiring of the generator head.

Cheers from Australia