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Electrical 101

Electrical issues
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panfreak
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Posts: 198
Joined: Tue May 18, 2004 6:46 pm

Electrical 101

#1

Post by panfreak » Sat Apr 30, 2005 1:36 am

My '58 project is almost done. I have been putting in some late nights so I can ride this summer, and now I'm wiring. I went 12V, with a solid state relay. Cloth covered wire arrived for vintage look, and there is now another section of my shop manual with dirty prints all over the pages. The manual is great for data, but doesn't answer many questions, and I'm having a hard time getting a working understanding of what roles each piece plays in the charging system. I can run wires here to there, but it doesn't feel right not "getting" it.
Here's where you all come in: could someone please walk me through (in laymans terms) what exactly the relay, generator, condenser and coils functions are, and how they're supposed to interact with each other? Just knowing what they are called and where the wires are connected won't help me if I'm stuck on the side of the road somewhere. I know this is a giant leap back to grade one for some of you, but if I didn't love working on and learning about bikes, I wouldn't be here. Thanks in advance...



kell
Posts: 404
Joined: Sat Jun 19, 2004 2:58 am

Re: Electrical 101

#2

Post by kell » Sat Apr 30, 2005 12:12 pm

Check this out for an explanation of the ignition system http://www.mrbean.net.au/~rover/ketterin.htm" onclick="window.open(this.href);return false;

About the charging:
The generator has two circuits or sets of windings. One is the armature (A). The field (F) is the other one. The amount of current flowing in the field determines the amount of power that comes out of the armature, because the field is actually an electromagnet and the strength of the magnetic field generates the electricity in the armature as it spins around. So the voltage regulator is able to control the power by controlling the amount of current in the field; and the power that is generated comes out of the A terminal and is directed through the voltage regulator to the battery. I'm not sure of the standard setup but on my bike the battery is connected directly to this ouput, it doesn't go through the ignition switch. The charging current, when it peaks, is the highest current you will see anywhere on the bike and might overheat a switch.

panfreak
Panhead Register Member
Posts: 198
Joined: Tue May 18, 2004 6:46 pm

Re: Electrical 101

#3

Post by panfreak » Sat Apr 30, 2005 7:03 pm

Kell,
Thanks a million, that is exactly what I was after.

57Kicker
Posts: 51
Joined: Fri Jul 13, 2007 8:47 am

Re: Electrical 101

#4

Post by 57Kicker » Sun May 01, 2005 5:25 pm

On the topic "electrical 101", I want to replace some of the wiring and connectors on my 57 to ensure solid connections by soldering all joints. While I am doing this I thought about "upsizing" some of the wire guages. For example: generator to regulator use 12 Guage wire. Coil to breaker use 14 Guage wire. etc. I think this is only one guage more than whats there now.
I guess my question is, would there be any adverse effects by running heavier wire for this application? Or does it matter? I don't want to over work the electrics and risk toasting anything.
I have to get ol'Baxter back together soon 'cause I think spring is in the air!

THINK SPRING!!cheers!

kell
Posts: 404
Joined: Sat Jun 19, 2004 2:58 am

Re: Electrical 101

#5

Post by kell » Sun May 01, 2005 11:55 pm

If it's a really short run just make sure the wire gauge is big enough to carry the current without getting hot. On longer runs voltage drop depends on the length of the wire and becomes a determining factor.
There are plenty of resistance calculators on the web, here's one: http://www.csgnetwork.com/voltagedropcalc.html" onclick="window.open(this.href);return false;
Say you have a 6 ohm coil, it will draw no more than 2 amps (12 volts divided by 6). Choose a wire gauge, plug in the numbers and see how much volts you lose on the wire. Don't forget with this particular calculator you have to divide the length of the wire by two (if it's a single conductor, as the coil wire is).
If you size it for 0.1 volts drop you won't be losing anything. I use 16 or 14 gauge to the coil, don't remember.
For the charging circuit use total draw with lights on, plus ignition, plus charging current for the battery. The headlight draw would be the lamp's wattage divided by 12 if you have a twelve volt system. Charging current for the battery varies I'm not sure what the peak current is but call it 5 amps. Old bikes with small electrical systems you could use 14 gauge in the charging system, it's heavy enough to deal with the current, but you would get some voltage drop on the way from the genny to the battery. 12 gauge might be better.

Oh and in answer to 57 kicker you can't hurt anything by putting bigger wires on it.
And that calculator I linked to doesn't have a choice for twelve volts. Just click on 24, it doesn't matter. The calculation for voltage drop will come out the same.
Bootyful weather today. Time to haul a**.

57Kicker
Posts: 51
Joined: Fri Jul 13, 2007 8:47 am

Re: Electrical 101

#6

Post by 57Kicker » Mon May 02, 2005 12:03 pm

So Kell,
12 Ga. should be ok for my 12volt system on my 57. Here in Canada it is mandatory to run with lights on all the time. By the sounds of what your saying, the more current draw; (ie, lights on) the heavier gauge wire. Therefore 12 gauge from the gen. to the reg. and to the bat. and also for ground may be ok.
Thanks Kell

What a great site this is!

Jack_Hester
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Location: Roxboro, NC, U.S.A.
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Re: Electrical 101

#7

Post by Jack_Hester » Mon May 02, 2005 10:34 pm

57Kicker -

When you are choosing your wire, be sure to buy automotive types conductors. Must have many, fine strands. Don't purchase from home electrical supply, as these conductors are made with large strands. The point is flexibility. Road vibration, alone, is enough to break stiff conductors at the terminals. Another rule of thumb: 14ga - 15amps, 12ga - 20amps, 10ga - 30amps.

Jack

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