Comet Electrics

mercurycrest

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VOC Member
Well, since I've been riding and repairing my Series A for 46-1/2 years, I figure I know what it is..or, isn't. Once a nice old man even told me he thought he'd built it. So, I asked him to autograph it. :)
Series A being signed by PEI 1.jpeg
 

Desmond

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VOC Member
Hooked a new 6 volt battery up to the comet but no idea which wire goes to positive or negative. Hook it up one way and lights work with ammeter needle sitting high then when I switch switch connections lights still work and ammeter sits just below Half way which seems more normal. Any ideas?
 

Desmond

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VOC Member
They were Negative earth as standard but there are now many new voltage reuulators available and some of them require Positive earth as I have just found out with my '51 Comet.
 

Andy H

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VOC Member
Original neg earth which is ideal if you hook up satnav or phone charger when touring. I know most gadgets work off 12v but my Garmin adapter seems happy with 6v on my Rapide and took me to Italy and back . I have now spoiled it by a rewound dynamo for 12v. However recently bought Comet which has pos earth with solid stare regulator and that was 12v. Has lucas dynamo but probably 6v one . I have converted back to neg earth as wiring loom was a birds nest anyway. How do i tell if lucas dynamo 6 or 12v ? Probably academic now as gone all led.
 

Martyn Goodwin

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Non-VOC Member
Original neg earth which is ideal if you hook up satnav or phone charger when touring. I know most gadgets work off 12v but my Garmin adapter seems happy with 6v on my Rapide and took me to Italy and back . I have now spoiled it by a rewound dynamo for 12v. However recently bought Comet which has pos earth with solid stare regulator and that was 12v. Has lucas dynamo but probably 6v one . I have converted back to neg earth as wiring loom was a birds nest anyway. How do i tell if lucas dynamo 6 or 12v ? Probably academic now as gone all led.
The original dynamo, intended as 6 volt actually produces over 20 volts - its the voltage regulator that makes ties the output to 6V.

The difference between a purpose made 6 and 12 volt dynamo is in in the gauge of wire and the number of turns of same on the armature. When rewound for 12 Volts the dynamo needs to spin faster to produce the same volts (but possibly at higher amps).

Having gone full LED and a 12V regulator, it matters not if the dynamo is 6 voly or a 12 volt conversion as the current required (amps) is miniscule compared to incandescent. Its the regulator that controls the plot!
 

poor1

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Non-VOC Member
Martin. You suggest checking with a multimeter before starting the engine. How exactly would you know whether it was negative or positive earth?
 

poor1

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Non-VOC Member
Martin. Now that it is established that Vincents do have a Negative earth could you possible enlighten me as to how it can be verified with a mustimeter as I am in the same position in not being sure which battery terminal should be earthed.
 

timetraveller

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VOC Member
Does your battery have a plus sign and a negative/minus sign built into the casing. If it does then it is easy. Connect the one marked with a minus sign to the earth of the bike. Lacking these markings you can use the multimeter. Make sure that the black and red wires are connected to their colour matched terminals on the face of the multimter and then switch to volts/DC/12v(or whatever). Then connect to the battery terminals with red to positive and black to negative. If the battery terminals are unmarked then just connect up and see what reading you get. Provided that you have the right wire into the right terminal on the meter then if you see six volts on the meter then the black wire is to the negative and the red to the positive. If you see minus six volts then the red it to the negative and so on. If all this is beyond you then find a normal dry cell battery as used in a torch, portable radio or similar and repeat the exercise. Such batteries are clear;y marked at their positive and negative ends. If all this is beyond you then find a child of ten to twelve years old and ask them to help you. Any yoiungster with an interest in modern gadgets will know what to do. Failing all this then is there a local section of the VOC within a reasonable distance? Someone there can probably help.
 

poor1

Well Known and Active Forum User
Non-VOC Member
Does your battery have a plus sign and a negative/minus sign built into the casing. If it does then it is easy. Connect the one marked with a minus sign to the earth of the bike. Lacking these markings you can use the multimeter. Make sure that the black and red wires are connected to their colour matched terminals on the face of the multimter and then switch to volts/DC/12v(or whatever). Then connect to the battery terminals with red to positive and black to negative. If the battery terminals are unmarked then just connect up and see what reading you get. Provided that you have the right wire into the right terminal on the meter then if you see six volts on the meter then the black wire is to the negative and the red to the positive. If you see minus six volts then the red it to the negative and so on. If all this is beyond you then find a normal dry cell battery as used in a torch, portable radio or similar and repeat the exercise. Such batteries are clear;y marked at their positive and negative ends. If all this is beyond you then find a child of ten to twelve years old and ask them to help you. Any yoiungster with an interest in modern gadgets will know what to do. Failing all this then is there a local section of the VOC within a reasonable distance? Someone there can probably help.
I suspect you have gone to great lengths to be felicitous.
 
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