Model A horn problems

Ian NZ

Ian NZ

Well-known member
What is the best way to test the windings and armature on a Sparton model A horn. My horn works allright when you rev the engine up when the generator is charging, but when it is not charging its not very good, so I was wondering if the horn needs rewinding.
 
Ian,

It seems that there is not anything wrong with your horn. The problem is that your generator is not turning fast enough to produce the required voltage at idle.

Look at your generator. It may be the one that need attention.

Should you need me, I am here.

Neil Stegall
THE HORN MAN
601-469-0878
 
Have you cleaned the armature to very bright and lubed the felts with a drop or two of light oil?
Also try "Hot Wiring" from the battery to the horn directly to determine if its the horn or the connections.
 
If oiling & cleaning doesn't help, that little supplied horn relay, that hides inside the horn cover, will usually do the trick. If running a 6 Volt alternator, the horn always sounds good, even at an IDLE.
Bill W.
 
I have lubed the felts and cleaned the armature and I do have a relay tucked under the frame connected to the horn so therefor the discharge will not show on the ammeter, and I am running a 6 volt generator with a Fun Projects Regulator just that I was wondering if there is anyway I can test the horn windings.
 
A properly adjusted and working Model A horn draws about 4 to 5 amps while running steady. If your's draws more then it is likely shorted or adjusted too tight.
 
The above information is correct. However, be sure to clean the groves in the commutator with a popsicle stick or a wooden skewer. It will make a difference in the performance of the horn.
 
Have you tried changing the adjustment -with my car the best idle parage adjustment is one click out from the best on the road adjustment, most times my only parade prep is to take off the cover and clean the commotator with a rag and make the adjustment

I do have a better connection at the top of the horn button and the bottom--I use this to have the horn make different sounds during parades
 
Ian NZ said:
What is the best way to test the windings and armature on a Sparton model A horn.
Click to expand...

Unless you have specialized equipment (growler) any method of testing will be just ok and not the best.

Have you tested the horn by temporarily hooking it up to the battery?
Have you replaced the relay that you are using for the horn?
 
Ian NZ said:
I have lubed the felts and cleaned the armature and I do have a relay tucked under the frame connected to the horn so therefor the discharge will not show on the ammeter, and I am running a 6 volt generator with a Fun Projects Regulator just that I was wondering if there is anyway I can test the horn windings.
Click to expand...

I guess what we are doing a poor job of saying is that we do not believe you have a winding problem.

What we do need to know is exactly how the relay is wired. Where does the supply voltage to the battery come from? The horn works by supplying a voltage from the battery to one terminal of the horn, it goes through the horn, and then to ground and the battery.

Where is the relay, before the horn of after the horn? Need to know this so as to point you to where you need to measure voltage.
 
Mike V. Florida said:
I guess what we are doing a poor job of saying is that we do not believe you have a winding problem.

What we do need to know is exactly how the relay is wired. Where does the supply voltage to the battery come from? The horn works by supplying a voltage from the battery to one terminal of the horn, it goes through the horn, and then to ground and the battery.

Where is the relay, before the horn of after the horn? Need to know this so as to point you to where you need to measure voltage.
Click to expand...

There are three connections on the relay, the main supply to the relay points connection comes from the main supply connected to the light switch, another switch or points connection on the relay is actuated by the horn button, and on the other points connection on the relay which goes to the horn motor which is earthed too ground through the frame.
 
Ian NZ said:
There are three connections on the relay, the main supply to the relay points connection comes from the main supply connected to the light switch, another switch or points connection on the relay is actuated by the horn button, and on the other points connection on the relay which goes to the horn motor which is earthed too ground through the frame.
Click to expand...


If wired as you describe, then the horn should show up on the ammeter.

Anyway, get a volt meter;

Measure across the battery. Record the voltage. you should have over 6 volts, if not you have a battery or generator/regulator problem. Fix that.

If you have 6 volts or more, get some wire and remove the leads from the horn and go directly to the battery. If the horn does not blow then you have a horn problem.

If the horn blows, then measure the power lead from the relay by having someone blow the horn, record the voltage. Should be the same as the battery.

Connect the meter across the leads that go to the horn, have someone blow the horn, record the voltage. It should be the same as the battery.

That's enough to start, let us know the results, then we can move on.
 
Mike V. Florida said:
If wired as you describe, then the horn should show up on the ammeter.

Anyway, get a volt meter;

Measure across the battery. Record the voltage. you should have over 6 volts, if not you have a battery or generator/regulator problem. Fix that.

If you have 6 volts or more, get some wire and remove the leads from the horn and go directly to the battery. If the horn does not blow then you have a horn problem.

If the horn blows, then measure the power lead from the relay by having someone blow the horn, record the voltage. Should be the same as the battery.



Connect the meter across the leads that go to the horn, have someone blow the horn, record the voltage. It should be the same as the battery.

That's enough to start, let us know the results, then we can move on.
Click to expand...


Thanks for the advise Mike, I will find a Volt meter and do a few tests, what I have noticed if I charge the battery up with a battery charger and fully charge the battery even if I leave the car for a few days and blow the horn, it works good as gold, I wonder if I have a generator problem but I will carry out the tests you describe.
 
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