Finished the hybrid-electric Power Wheels

[Ukraine Train]

If you missed it, I was asking about how to wire this thing up a while back. Well today we finished it and ran it for a few minutes with no problems. The two motors are 6V each so we originally wired the fog lights and motors in series so that the 14V from the alternator got knocked down but the car was really slow so we rewired the lights on a separate circuit and then just wired the motors in series so they get 7V apiece.

[onions!]

That's pretty cool.Bonus points for creativity.

[cfabe]

I espicially like the osha-approved FingerGrinder (TM) chain guard.

[280plus]

Hah, very cool. So the motors DO work in series. Interesting...Nice work!

[crt360]

Looks great, glad it worked.  What's the function of the little hopper looking piece on top of the engine?

[Ukraine Train]

Looks great, glad it worked.  What's the function of the little hopper looking piece on top of the engine?

The engine we used came from an old Mini Baja car. One of the rules for that race series is you have to have a splash pan around the fuel tank which drains down a hose to the ground. That's the hopper-type thing up top.

[grampster]

I was thinking it was the hopper for recycling body parts caught in the chain.  

[280plus]

(i'm baaaack...)

Anyhoo, I did a little research. Turns out I was thinking the only path for current was through the armature windings. Which would be true for a dc motor with permanent magnets. I did not think of the fact that those motors use a field winding instead of a magnet so the path is provided by the field windings in series.  So even I learned something from your experiment.

Thanx!

(sorry If I put you through a lot of extra work with the light thing)

I'm curious though, did the lights light up when they were in series with the motors?

[Ukraine Train]

Yes they lit up when in series with the motors, really bright too.

[280plus]

Hmph,,,again not what I would havwe expected. When you're done with it can you cruise it over to my house? I want to take a few readings...

[280plus]

Hey Ukraine...  

I was mulling the circuit over in my head some more and I was curious. When you had the lights in series with the motors did it go positive - lights - motors - negative? If so, would you mind terribly trying it positive - motors - lights - negative and see if that has a different result? I seem to remember something about dc being directional.  You know after you're done with it and have a few minutes sometime. It's not a biggie, I'm just curious.

[Ukraine Train]

I'm moving home today so I won't have time to play around with it but I imagine it would run in reverse and being that the lights are just resistors they'll still light up.

[280plus]

Thanks for the reply,
I'm thinking whatever sees the current first takes everything it needs and only the leftovers get past it. So if the lights were in the circuit "upstream" from the motors that might be why they got so bright and the motors ran so slow. Mind you this is just a guess on my part but I'm curious to know if it's right. Incidentally, if you do try it and the motors go real fast, don't run them for more than a couple seconds. We don't want to let the smoke out of them. Cause that's a nice little contraption you built there.

If you have no time don't worry about it. Someday I'll get a wild hair going and buy some cheap components at radio shack and try it myself. It's not at what you would call at the top of my priority list right now either.

[zahc]

The current in any part of a series circuit is the same, it wouldn't matter which 'side' the lights were on. Consider that the conducting electrons also flow opposite the direction of conventional current; terms like upstream don't make much sense.

Putting loads is series sums the resistences, so the more stuff you put in a series loop, the less current you will have with a given voltage.

[280plus]

I just find it interesting or baffling that the lights were really bright but the motors ran slow when in series with each other. Seems like the lights were sucking up all the voltage and not leaving much for the motors. Ah well, as long as he got it to work, even with my "help"...

[cfabe]

The lights have a much higher resistance than the motor, so it worked as a voltage divider with the lights getting most of the voltage. If the motor was 1 ohm and the light was 6 ohms, the lights would see 10 volts and the motor only 2 volts.

[280plus]

Ah, that makes sense. The lights were bright because they were using up more than 6V but there wasn't enough left to run the motors. I see said the blind man. Thanks for bearing with me!

Yup, I figgered it out. The field windings on the motors must have next to nothing for resistance. The lights just had way too much resistance in relation to the motors for it to work that way.

I'm STILL learning something new every day...

One of these days my head may just explode from all the knowledge stuffed in there though. It won't be pretty.