Sparton Horn Wiring

[mill48]

Hello guys. I need help in wiring a new 12v organization horn. I had expected it would come already wired. I know I have to take the motor cover off, but how do I wire from there? I already have a relay installed with the hot(red) wire running straight to the battery. It's a 12V horn.

[alexiskai]

What's an "organization" horn?

[mill48]

That was a typo.
I meant Sparton horn.

[brokenspoke]

The search function is your friend

[mill48]

Are there any horn experts in this thread?

[katy]

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A picture of the inards would help.

[alexiskai]

If you're just asking "how do I hook the horn up to the car," the standard wiring harness has two wires, blue and yellow, with bullet connectors, that emerge from a conduit into the radiator shell. The yellow wire goes to the cutout/alternator and provides a live 6V connection at all times. The blue wire routes into the light switch and then to the horn rod. When you push the horn button, it closes the connection to ground, which completes the circuit and sounds the horn.

The horn has two copper terminals below the motor frame, mounted on top of an insulating block. There should be a channel in the insulating block when viewed from the side. The bullet connectors insert into this channel and are held in place by the copper terminal. It doesn't matter which terminal you connect the blue or yellow wire to, it works either way.

I recently released a video on assembling the horn that shows the horn motor area and briefly discusses proper connection of the wires. The video is very long, but if you skip to the last few minutes you may get some helpful info.

[mill48]

Here are pictures of the horn insides.

[alexiskai]

Insert connectors on either side of the terminal block as shown with arrows

[rotorwrench]

Series wound motors are not polarity sensitive. They will function and in the correct direction of rotation either way.

[alexiskai]

Originally Posted by rotorwrench

Series wound motors are not polarity sensitive. They will function and in the correct direction of rotation either way.

How does that work? It was my intuitive sense that reversing the connectors would reverse the rotation, but no, huh?

[mill48]

Originally Posted by alexiskai

Insert connectors on either side of the terminal block as shown with arrows

What type connectors go there?

[alexiskai]

See photo

[mill48]

Are those like bullet terminal connectors?

[rotorwrench]

Originally Posted by alexiskai

How does that work? It was my intuitive sense that reversing the connectors would reverse the rotation, but no, huh?

Not on series wound. Starter motors are series wound to give the high torque needed for starting and they can be positive or negative ground and still spin the same direction of rotation. Series wound use a lot of amperage to work so they are generally only used for high torque situations.

[mill48]

What's the name of that wire and where can buy it. I know I can get the bullet ends at almost any auto parts store.

[rotorwrench]

The type and size of bullet connectors used on the early Fords are not as common as they used to be. Many are machined from brass now and can not be crimped like those in the photo (post #13). The good ones are formed from sheet brass or copper and are tinned for corrosion resistance and easy soldering for those that solder them, The machined brass replacments have to be soldered.

Reproduction cloth covered wire in multiple types of color coding is available from parts sources and is fabricated by several sources such a Bauer Electronics and Rhode Island wire to name a few, The better the quality the higher the price. Standard main electrical harnesses come with all the normal wiring for the model A with a few exceptions. Most Model A parts sources carry them. Bauer makes a lot of these but there may be other sources from different model A parts retail sources.

I like Rhode Island wire since they coat the cloth outer jacket to give it better color retention over time. Cloth colors tend to fade quickly under normal use.

[mill48]

Thanks guys. I tested my horn and it works. Your knowledge is greatly appreciated.

[Badpuppy]

Originally Posted by alexiskai

How does that work? It was my intuitive sense that reversing the connectors would reverse the rotation, but no, huh?

The coils are wound so the fields oppose each other. They're connected in series, so in reversing the current the fields still oppose.

When one of the windings is replaced with a permanent magnet, reversing current reverses rotation.

[dlamm]

I just had the same question. Thanks for the great photo
Dean