Horn Motor Armature ?

[JBR]

Using my ohm meter to check continuity from one brush of my horn motor to the other I get continuity. Checking the armature segments where the brushes ride I get continuity between segments.

Is this correct. Shouldn't the brushes and segments be isolated from one another?

Hope this makes sense.

Thanks,

Jon

[JBR]

OK, I put a piece of paper between the brushes and armature. No longer any continuity between the brushes. No continuity between the brushes and armature.

No continuity between the frame (ground?) and the brushes or armature segments.

I still have continuity between the armature segments themselves.

Now what?

Jon

[JBR]

Correct the horn doesn't work. I was going to send it in to by rewound. When I took the cover off the horn to unhook the wires I saw a broken wire from one of the brushes to one of the field windings. When I got the horn off the truck I saw that one of the windings was crispy. The smoke done left the wires. I thought I would try to rewind the burnt side. Best case scenario is it worked and I saved some money. If it didn't I really wasn't any worse off then before.

I got some #20 wire and rewound the burnt side. It work a couple of time and then quit. I was trying to figure out what I did wrong. I'm not and electrician.
Jon

[mrtexas]

The wiring is simple. The field coils should show continuity and about <1 ohm resistance. They are wound opposite to each other.

Think of the armature as a single wire cut in 6 pieces by the commutator bars(the strips the brushes contact). Be sure and sand the commutators with fine sandpaper as the motor won't work reliably if there is any corrosion. See if you can get the motor to run while turned on by giving the armature a spin.

I'm not an electrician either!

[JBR]

I went out an tried it again. Before I was using a couple of small jumper wires with clips and going from the fuse to a head hut. Nothing.

This time I got some heavier wire (16 Ga.) and went directly to the battery terminals. I got it to run. But there must be a dead spot somewhere because every once in a while it will stop and won't start again until I turn the armature a little.

Unfortunately I can't get it to run quite fast enough to give me a nice ahooga. It is almost there, but not quite.

I have one spring that I got at the hardware store that is a little stiff. Maybe with new springs, brushes, a relay, and a fully charged battery or the motor running i might get it.

It least the operation wasn't a total failure.

Any additional advice would be greatly appreciated.

Thanks for you help,
Jon

[Tom Wesenberg]

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Hold some fine sandpaper against the commutator while it's spinning. That will polish it up for a much better connection to the brushes. I've never found a need to install a relay.

[JBR]

I used 300 emery cloth on it today per Les Andrews. I have some 400 & 600 wet & dry I'll try tomorrow.
Thanks,
Jon

[Ron in Quincy]

Use a piece of regular fine wood sandpaper, not wet or dry, to clean the commutator.

For 6 volt horns, the original field coil wire was 20 guage. Using coated wire, make 45 turns per field; 6 or 7 turns per layer, not perfect is ok. After completed spray with varnish or insulating enamel. Remember the two field coils are wound in opposite directions.

Ron

[JBR]

I used #20 wire. I made 48 turns per Les Andrews. 4 layers of 10,and one of 8. I tried to keep them as neat as possible. I wound it in the opposite direction it came off.

45 or 48? Does it really make that much difference? I can redo it if it does.
Thanks,
Jon

[Tom Wesenberg]

Originally Posted by JBR

I used #20 wire. I made 48 turns per Les Andrews. 4 layers of 10,and one of 8. I tried to keep them as neat as possible. I wound it in the opposite direction it came off.

45 or 48? Does it really make that much difference? I can redo it if it does.
Thanks,
Jon

3 turns won't matter.

[JBR]

In other words, you are saying I should do the other field coil too? No problem. I can do that. Right now we are headed to a club picnic. I'll do it later this afternoon or tomorrow.
Thanks Everybody,
Jon

[JBR]

Make sense. I will do the other one tomorrow. We had a nice picnic with the club today, but now I'm tired.

Let's say I rewind the other field coil and it doesn't help and that the armature would than be suspect. Then what I do? I understand that armatures are not available and I'm nut sure I want to tackle that sucker.
Jon

[Mike V. Florida]

I would think a motor repair shop could do it, rewind the armature.