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Old 19-12-17, 08:45 PM   #1
Bravemeister
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Default 1.75 kW startomatic no output, diode?

Hi All,

Since my last post I have bought a replacement alternator for my now running engine. This is the same alternator, however comes with the startomatic panel.

I have connected everything up as it should be, started the engine by connecting a 500W halogen lamp to the output on the panel.

The genny does not however output.... Well, it will but I'm having to manually pull the switch contact that makes about 5 contacts in one go. I've identified a potential cause for the coil not actuating the contacts and relying on me doing it manually - the diode(s).

On the electrical diagram it looks as though there are 3 diodes in a row, something i'm not familiar with..... This unit is an "all in one" with 10 fins coming off it, so I imagine it gets hot. If I were to go about testing this unit how would I do it, failing that, If I were to get a replacement part, what should I be looking for?

I can post pictures, but where am I putting them as they are bigger than the forum limit allows.

Regards,

Matt
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Old 19-12-17, 10:49 PM   #2
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Quote:
Originally Posted by Bravemeister View Post
...<snip> I can post pictures, but where am I putting them as they are bigger than the forum limit allows.

Regards,

Matt
Have you tried re-sizing the pictures with something like IrfanView

Stuart.
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Old 19-12-17, 11:12 PM   #3
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The grey thing in the bottom right corner, electrical diagram to follow.
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Old 19-12-17, 11:17 PM   #4
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The 3 diodes in a row "LCR". I cant get a reading across it when doing a diode check.

On the other single diode I get 0.303 voltage drop.
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Old 19-12-17, 11:22 PM   #5
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I think you're looking for a Selenium rectifier

Stuart.
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Old 20-12-17, 12:46 AM   #6
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Looks like a signal diode array, scroll down to 'signal diode'.

http://www.electronics-tutorials.ws/diode/diode_4.html
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Old 20-12-17, 11:34 AM   #7
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Some 'signal' if it needs all those fins!

I agree with Robotstar - metal rectifier, be it selenium, copper oxide or whatever. Could probably be replaced by a suitably rated silicon job if it is kaput (does it smell of old cabbage?)

NHH
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Old 20-12-17, 01:53 PM   #8
listerdiesel
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Drop me your postal address, I'll send you some axial diodes.

Peter
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Old 20-12-17, 02:31 PM   #9
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Some 'signal' if it needs all those fins!
My first thoughts exactly, just based my search on the diode symbol on the drawing.
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Old 20-12-17, 03:01 PM   #10
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Technically, the finned Selenium rectifiers are multiple semiconductors in a series configuration to give the required Vrrm voltage, a single silicon diode will do the same job.

Peter
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