Electricans! Howcome I'm blowing bulbs. Help!

[leprogle]

I have an 83 185s motor, I put a 75 watt Ricky Stator lighting coil in it, so that I could run a 350x headlight, with 35watt bulbs. I think I had the coil wired backwards the first time, and that may have been the reason for blowing the bulbs. At first I had 12v25/25w regular bulbs and they blew, as soon as I revved the engine over idle. I pulled the flywheel, and flipped the coil around. Then, I fired it up and tested with a voltmeter. I got 7/8v at an idle, and when revved, shoots to 50-60+v. I then tried the stock 185s headlight: 12v45/45, which worked fine. However I now purchased new halogen 12v35/36.5w bulbs, they run at an idle, but I am afraid to try it over that, as they are $15 a pop, versus $5 for the regular.
Do you need a special bulb to run on only a magneto? are the bulbs I have now, only good for 12vDC off a battery, voltage regulator, and rectifier? the magneto produces AC, is that why my bulbs are blowing?
please help!
thanks
Jon

[Somekindofjerk]

You need a voltage regulator. If you dont use one your getting full power all the time even if it revs out it will pump that full power to your headlights. Get a regulator for an X and figure out using the 350X wiring diagrams how to wire it in.

[leprogle]

Is that all is need is just the regulator? would I need the rectifier too to change it to DC? or just the regulator?

[Somekindofjerk]

Just the regulator should get you all fixed up.

[YTM200BOY]

Yep voltage regualtor is probably your issue............

[dirtybiker71]

There is also an aftermarket regulator on the market by MSR and Moose. It is a 2 wire universal set up that sells for under $20 and comes with super easy instructions. Just make sure that you wire it up into the lighting circuit AFTER the switch, or between the switch and the headlights. In this way, you are shutting off power to the regulator also when the headlights are off. If this is not done, the regulator will be trying to dump off all of the power that the lighting coil can put out all the time and will overheat. You don't need to convert to DC. Lightbulbs don't know the difference. You would only need to do that if you were going to charge a battery from this source as they are DC. It is normal for a lighting coil (on your stator) to put out that type of high voltage under unregulated and open circuit conditions.

[leprogle]

I got a voltage regulator off of a 250sx, and I only used two of the yellow wires. The one beside the red, and the green. Going by the wiring diagram in the clymer manual, I put the yellow and green from the lighting coil to the yellow wires on the regulator. I then put the red from the regulator to the yellow, which is the feed for the light switch, and then hooked the ground to the ground going to the switch.
I started the bike up, and tested the two lighting circuits, it is the same 7/8v idle, and 50-60 or when revved. However it is now DC. Should that work? It does say dc on the bulb, so I assume the AC is what cooked the bulbs.
I greatly appreciate the input, hopefully I'll have headlights for the weekend!
thanks
Jon

Oh, see what you mean, I should probably hook it between the lights and switch, instead of stator and switch.
gotcha, will have to try that

[dirtybiker71]

The voltage is what kills the bulbs, not whether it's direct current (DC) or alternating current (AC). Seriously, it makes no difference to the bulbs one way or the other. I have a degree in electronics and have worked as an electrician. You may be able to make the 250SX regulator work and if it ends up changing the voltage to DC it will work fine. Actually that particular regulator will have a rectifier in it which is the part that changes AC from the stator to DC to charge the battery since that was an electric start, battery powered machine. The 3 yellow wires were the input to the reg or the output from the SX stator. (3 wires for the 3 phase stator. ) The red one should have been the regulator output, or the regulated 12VDC which then was sent to the battery. Typically on Honda applications the green would be the ground. Sounds like you hooked it up right, but the one thing I'm not certain about is whether the 3 phase regulator will work at all with your single phase stator. On simple lighting systems like the original one on the 185 motor that don't use a regulator, the output of the lighting coil part of the stator is simply matched to the power consumption of the bulbs. (Which is determined by the internal resistance of the filaments.) This is why, for the most part, you can only use the original type bulbs in these systems. Others will just be dim, or too bright and burn out quickly. I have used the ricky stator lighting coils on motocross bikes to add lights to off road machines, but always used the aftermarket 2 wire regulators with good success. Good luck!

[ATCnut]

The 250sx regulator will not work. The sx has a three phase generator, to charge the battery. You have a single phase You need a regulator off of a 350X, or the generic aftermarket one. The AC is not killing your bulbs, the voltage is.

(FYI I'm an electrical engineer, been doing this stuff for 20+ years)

[Rex Karz]

And don't forget, the proper regulator is a shunt regulator, it shorts the excess voltage to ground. It also shorts all of the negative pulses to ground.

[leprogle]

I had it out for a rip last night, and the lights worked good.....for an hour or two, they then suddenly stopped working, they flicked on once, about 5 min later, and then back out, so i just turned them off, I'm going to have to look into getting one of those aftermarket jobbies probably.
I checked my bulbs and they're still good, i think, I didn't meter them, but the filaments looked good.
Thanks guys, I'm an apprentice electrician, myself, but i've only been at it for a year, thanks for the input.
Jon

[leprogle]

How would I wire a 2-wire uni, or 350x in? it's only 2 wires on either isn't it? does it just go in series on the hot wire?

[ATCnut]

The two wire uni unit, or the 350X unit goes in parallel with the bulbs. It is a shunt regulator, when the voltage gets too high for the bulbs, it conducts and clamps the voltage down to a level the bulbs can withstand.