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Author Topic: LD1 Start-o-matic resistor ratings ?  (Read 8751 times)

smeghead

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LD1 Start-o-matic resistor ratings ?
« on: May 05, 2015, 12:10:26 AM »
Hi

I've got a LD1 SOM that i'm trying to get fully working, it runs and generates fine in manual mode, just the SOM part has never worked as long as I've owned it.

So far I've repaired the detection coil and a bunch of other issues, so it now it starts automatically when required but the main contactor doesn't operate. I've tracked it down to both the variable resistor and the 6k8 fixed resistor that limit the voltage/current to the contactor windings have both failed open circuit.

What power rating should these be ? they both look fairly hefty so I'm guessing at least 5 watts possibly 10 or 15 ?  I've checked the continuity of the contactor coil at 4k7 so I'm hoping that's ok.

Does anyone have the manual for this machine available to download?   I'm currently working off the diagram inside the control box but bits of it are missing.

Thanks.

oldgoat

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Re: LD1 Start-o-matic resistor ratings ?
« Reply #1 on: May 21, 2015, 02:16:36 PM »
The current through the start relay is only about 30 milliamps at 230v so a 5 watt resistor should be fine.

oldgoat

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Re: LD1 Start-o-matic resistor ratings ?
« Reply #2 on: May 21, 2015, 02:19:33 PM »
Send me your email and I will send you the circuit

smeghead

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Re: LD1 Start-o-matic resistor ratings ?
« Reply #3 on: May 23, 2015, 09:34:09 PM »
Send me your email and I will send you the circuit

Thanks oldgoat for the diagrams, the SL2-SOM.jpg diagram is similar to the one in my control box but does have a few differences regarding the connections to the DC section of the generator.

I'll take a photo of the (incomplete) diagram in my control box and post it up shortly.

Is the AC side of it adjustable ? as the voltage output is a little bit low at the correct frequency.

oldgoat

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Re: LD1 Start-o-matic resistor ratings ?
« Reply #4 on: May 24, 2015, 02:16:18 PM »
The brush position has a lot to do with the output voltage you can rotate the brush plate and also alter the series resistor on the shunt field to lift the voltage a bit. The auxillary field is the part that does the regulation set the current through it at about 4 amps as a starter and see how well it compensates for a big load.

smeghead

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Re: LD1 Start-o-matic resistor ratings ?
« Reply #5 on: May 25, 2015, 08:13:10 PM »
Here's a photo of the circuit diagram from inside the control box.



As you can see it's a little bit different to the one you sent me.