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Author Topic: Startomatic wiring advice  (Read 476 times)

Dill-the-Dog

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Startomatic wiring advice
« on: September 26, 2022, 06:38:48 PM »
Hi, I'm a newbie to this site, but have been struck by the collective expertise on show.

I live off-grid in a small 1830 cottage on the Isle of Man. I have recently bought an SR2 6KW statomatic generator, with the intention for it to be a back-up power supply when renewables fail me. However, I need power to build the infrastructure to house everything, so until then it is my only source of electricity. Or it would be if it worked!

The engine starts easily by hand or by the start button on the control box. However, as soon as the lock on the throttle is removed (for hand-start) or if the start button is no longer pressed, the engine dies. The decompressor solenoid is working. The generator generates AC power when running. So the problem is with the electronic throttle control.

The mechanics of the throttle are free and in good order. I have had the throttle solenoid apart and that looks OK. Have tested both coils and the resistance is correct for the gauge of wire and number of turns, and it clearly works with the push button start. So I guess it must be in the control box.

I have attached photos. You can see someone has done quite a bit of messing at some point. It bares a resemblance to the circuit diagram and photos of other control boxes on this forum, but there are extra bits!

Any pointers gratefully received. Until that point I'm on headtorches and candles.

Thanks,  Sean

ajaffa1

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Re: Startomatic wiring advice
« Reply #1 on: September 26, 2022, 10:12:19 PM »
Hi Sean, welcome to the forum..
These Startomatic engines and control panels are old and appear to be very complicated. In reality they are very robust and quite simple. They do have a number of old selenium rectifiers and bridge rectifiers, which break down with age, I would recommend you replace all of these with modern silicon rectifiers/diodes.
It sounds, from your description, that the problem lies with the fuel control solenoid or the circuit that feeds it. When the engine is starting, the large solenoid coil is energized moving the solenoid and opening the rack on the fuel injector pump. Once the engine is running, only the small solenoid coil is energized, keeping the rack on the injector pump open.
There is a small set of contacts hidden under the top cover of the fuel solenoid check the condition of the contacts, if they are dirty or misadjusted the engine will start and then stall.
If you follow the wiring back from the fuel solenoid to the control panel you should be able to identify the relay that it is attached to. Check the condition of those contacts.
Good luck,
Bob

Dill-the-Dog

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Re: Startomatic wiring advice
« Reply #2 on: September 27, 2022, 09:36:06 AM »
Hi Bob,

Thanks for getting back to me. The picture of your control box was one of the ones I was admiring when researching solutions.
I've heard about the selenium rectifiers issue. I can't see anything that looks like one (cooling fins etc). The the alternator box and generator head have some big electrical component where I'd imagine them to be, but I don't know what they are.
There is a scattering of diodes in the control box (see original picture). 'D' has obviously been replaced by a modern relay. And there's an additional large component in the bottom right, again which I'm unsure about.
When I had the fuel solenoid apart I checked the points below the top cap, which seem fine.
Would it be worth, at least partially, starting again, using modern rectifiers (as you've described previously), making a better job with the diodes etc and generally tidying things up? Would it be worth returning 'D' to an original if I can source one? All advice gratefully received.

Sean

oldgoat

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Re: Startomatic wiring advice
« Reply #3 on: September 27, 2022, 12:21:20 PM »
One thing to check is the value of the capacitor in parallel with the D relay if it is too small D will chatter and release

ajaffa1

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Re: Startomatic wiring advice
« Reply #4 on: September 27, 2022, 10:58:18 PM »
Hi Sean, does your control box still have the wiring diagram in the back of the box? If it does could you please post a photo of it.
Sadly I lost all my wiring diagrams and technical manuals in the 2019 Australian bush fires, I also lost all my computerized info so I am having to advise you from memory.
I can see that someone has made some modifications to the control panel. D has been replaced with a modern relay. The large relay appears to have a 3 phase motor starter relay next to it (MTE) This is probably because the 240 volt contacts on the large relay have burned out.
I can see someone has replaced the selenium rectifier for D with a diode. I can also see a collection of diodes to the right hand side of your control panel, these would be replacements for the selenium bridge rectifier but I can`t see if they have been wired as a bridge rectifier.
A word of warning here: the large square condenser in the center of the control panel is rated at 4 Microfarads and is charged with rectified 240 volts, so it has a charge of around 360 volts DC. This is more than enough to kill someone, please be careful.
I would certainly be looking at tidying things up a bit, photograph everything in detail, as you go, for reference during the rewiring.
Let us know what you find,
Bob

Dill-the-Dog

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Re: Startomatic wiring advice
« Reply #5 on: September 28, 2022, 09:50:53 AM »
Thanks Bob,
Sorry to hear you were affected by the bush fires.
I've attached a photo of the circuit diagram.
I'm off work after today, so I'll do some more investigating. Thanks for the warning about the condenser. I had spotted that on the circuit diagram (it says 400V DC on mine). How long will it hold its charge?
Cheers,
Sean

ajaffa1

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Re: Startomatic wiring advice
« Reply #6 on: September 29, 2022, 08:51:07 AM »
Hi Sean, the condenser should discharge through the coil on the line contactor relay fairly quickly but don`t take any chances. Get yourself a multimeter and check before doing any work. I know this from personal experience after I accidentally shorted out that condenser, it blew the end off a screwdriver!

Bob

fikamu

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Re: Startomatic wiring advice
« Reply #7 on: November 15, 2022, 09:33:18 PM »
Hi guys,

Nice to hear, that some one else is also struggling with same Start-O-Matic systems ... I read one well done documentation and found that in the circuit, where I have drawn red lines, seems to be the fuel supply circuit, if I am not wrong. Please guys with better knowledge, help us, if my drawing is not okay or if there is some other issues to correct. I am working on with my drawing and trying to understand that robust component "wilderness" and maybe by that means, able to change all possible problem producers to new components. I'll follw this with high interest.

BR
Kari