Classic cars forum & vehicle restoration.

pryantcc · Joined: 07 Sep 2009 Posts: 88

Hi guys,
I have a 1948 Alvis. It came with two lovely shiney refurbished wind tone horns in a box. It looks like they have 6V stamped on the bottom. If I put them in series, will the 12V across them be divided in 2 and feed them both with 6V?

Is there any way I can tell if they are designed for 6 or 12V feed?

Thanks,
Paul.

Nic Jarman · Posted: Fri Oct 02, 2009 11:13 am Post subject:

Yes. If you put the 2 horns in series and put 12v across them that is fine. If you are wrong and they are 12v they may not sound or will be quite quiet.
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1936 Morris 8 Series 1
1973 MGB roadster
1977 MG Midget 1500
Dax Rush

ukdave2002 · Joined: 23 Nov 2007 Posts: 4105 Location: South Cheshire

The only thing to watch is that the 2 devices in series present the same load;

If you connected a 12v battery to a 6v 10watt bulb in series with a 5 watt 6v bulb, the 10 watt bulb would have 8volts across it and the 5 watt 4volts.

If you measure the resistance of the horns and they are about the same it will be fine.

Dave

47Jag · Posted: Fri Oct 02, 2009 3:06 pm Post subject:

Dave & Nic,

I'm not so sure it will work. The principle the horn works on as you are no doubt aware is that the points are closed, the coil is energised, pulls on the diaphragm, the points open and the diaphragm springs back. This on/off action repeats and at a frequency moving air in the trumpet to give the desired note. So now we have 2 horns in series. When horn A's points open it also cut the power to horn B . What sort of strangled sound are we going to get???? I've never tried it but would be interested to know the results.

Paul,

If you take the dome off there is a tag between 2 of the screws which has the voltage stamped along with all sorts of other stuff (Lucas part No., date of manufacture etc)

Art

traction39 · Joined: 19 May 2009 Posts: 399 Location: South Wales

I thought the voltage was supplied in "parallel" to overcome this problem and to allow the two tones - town and country?
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Alistair

Citroen Light 15 1953, "12" 1939,
Riley 9 Special 1932

Peter_L · Posted: Fri Oct 02, 2009 3:37 pm Post subject:

You may wish to check this out. It includes details of the coil resistance for 6V and 12 V models.

http://www.vintagemg.com/ArticlePDFs/THorns1-2.pdf