Electrical question?

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mjf65
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Electrical question?

Post by mjf65 »

After fitting the replacement 6V battery to my 1960 Model 31DL the lights and horn are working, however when I attached or remove the negative terminal from the battery I get a spark and also when the battery is connected it shows positive current on the ammeter. It might be charging with the motor running as it does move more towards full deflection on the meter but it's hard to say with the meter indicator swaying around? As soon as I disconnect the negative terminal the ammeter is back down to showing zero current. Any ideas where to start, I'm desperate to get out and ride.
bjimc
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Re: Electrical question?

Post by bjimc »

is the bike pos or neg earth and are you putting the battery cables the wrong way
Mick D
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Re: Electrical question?

Post by Mick D »

Hi

Something's wrong there - what year and model is the bike? Has the electrical system had any modifications?

When everything is switched off there should be no deflection on the ammeter - it should read zero and be centred.

If as you say it is reading positive when the battery is connected either the battery or the ammeter is connected the wrong way and you have an erroneous drain somewhere.

Post more details please.

Regards Mick
mjf65
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Re: Electrical question?

Post by mjf65 »

As far as I know the bike is still on 6V negative earth. It came without a battery so I checked both battery connections and the one that had earth continuity was fitted to the positive terminal and the other to the negative terminal. None of the wiring is standard colour coded as per the manual but it still has the original lucas voltage regulator and dynamo. As far as I'm aware it ran ok before Richard the previous owner stored it.

What are the advantages of changing it over to a negative earth system?
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dave16mct
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Re: Electrical question?

Post by dave16mct »

If the lead which had earth continuity was connected to the positive battery terminal then you have a positive earth system. I don't think there are any advantages of a negative earth 6 volt system (12v, yes).
Dave.
Mick D
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Re: Electrical question?

Post by Mick D »

Hi

Sorry missed the model and year in your first post :oops:

Your bike would originally have been positive earth so you have connected the battery as it would have been originally, so with the engine off and a drain on the battery the ammeter should read negative, (left of centre). So either the PO has wired the ammeter incorrectly or he's converted the bike to negative earth, (and you have the battery connected incorrectly).
What rectifier do you have fitted, is it an original pattern Lucas or a modern replacement?

Regards Mick
mjf65
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Re: Electrical question?

Post by mjf65 »

The bike is a 1960 Model 31 dynamo and magneto. It appears to have the original Lucas voltage regulator fitted.
Mick D
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Re: Electrical question?

Post by Mick D »

Ah OK

I think your wiring should be as here:

http://archives.jampot.dk/book/Owners_m ... Models.pdf

Regards Mick
mjf65
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Re: Electrical question?

Post by mjf65 »

Thank you all for your help, I've just sorted it, bit embarassing really. I had got the terminal connectors on the wrong way, simply switched over and all is good. The positive wire now has a wide piece of red electrical tape wrapped around it. Silly boy!
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clive
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Re: Electrical question?

Post by clive »

Enjoy the ride
clive
if it ain't broke don't fix
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