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Voltage reducer for 6v trafficators
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1stpop



Joined: 03 Dec 2007
Posts: 109

PostPosted: Sun Jul 18, 2010 6:09 pm    Post subject: Voltage reducer for 6v trafficators Reply with quote

I have recently changed my Morris 8 series e to 12v's and am trying to work out how to keep my 6v trafficators? They are in perfect order so am loathed to part with them or replace them especially if there is a simple way to still use them?

I have flashing indicators already on a separate circuit but would like to have the trafficators working if possible?
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WLC4EVA
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PostPosted: Sun Jul 18, 2010 8:32 pm    Post subject: Reply with quote

.
Get another trafficator of the same design.
Remove arm and keep amongst your spares.
Mount trafficator under dashboard.
Connect the additional trafficator in the circuit from the fuse to the trafficator switch.

Downside of keeping 6v trafficators on a 12v circuit is that they consume twice as many amps as 12v ones would, so be economical with their use.

If you've fitted an alternator rather than a 12v dynamo, use them as much as you wish.

Kind Regards, WLC
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PAUL BEAUMONT



Joined: 27 Nov 2007
Posts: 1281
Location: Barnsley S. Yorks

PostPosted: Mon Jul 19, 2010 1:04 pm    Post subject: Reply with quote

Sadly the heat generated is proportional to the square of the current, so even if you have an alternator fitted, use them sparingly - or keep a fire extinguisher handy! Surprised

Paul
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WLC4EVA
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PostPosted: Mon Jul 19, 2010 3:39 pm    Post subject: Reply with quote

.
"heat generated is proportional to the square of the current".

Whose law is that please Paul?
And how is it relevant please seeing that the current through the indicator will be the same as it was with the 6v system?

Kind Regards, WLC
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PAUL BEAUMONT



Joined: 27 Nov 2007
Posts: 1281
Location: Barnsley S. Yorks

PostPosted: Tue Jul 20, 2010 1:13 pm    Post subject: Reply with quote

You stated:
"Downside of keeping 6v trafficators on a 12v circuit is that they consume twice as many amps as 12v ones would, so be economical with their use".
"Joule heating, also known as ohmic heating and resistive heating, is the process by which the passage of an electric current through a conductor releases heat. It was first studied by James Prescott Joule in 1841. Joule immersed a length of wire in a fixed mass of water and measured the temperature rise due to a known current flowing through the wire for a 30 minute period. By varying the current and the length of the wire he deduced that the heat produced was proportional to the square of the current multiplied by the electrical resistance of the wire" Wikipaedia
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WLC4EVA
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PostPosted: Tue Jul 20, 2010 1:54 pm    Post subject: Reply with quote

.
Ah, got you Paul.

I think you will find that Joule had to double the voltage to get double the current through.
And that his deduction was not very clever.

Watt's Law is much more relevant to a discussion involving the heating effect of an electric current.

In any event, 1stPop wisely wanted to know how to continue to operate his indicators at 6v.
So no change there, and no need to worry more about fire extinguishers.

Kind Regards, WLC
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Nic Jarman



Joined: 05 Oct 2008
Posts: 1031
Location: Stoke by Clare, Suffolk

PostPosted: Tue Jul 20, 2010 3:49 pm    Post subject: Reply with quote

With a small amount of electrical knowledge it is quite easy to knock up a voltage regulator. The regulator should be bolted to the car body as it will dissepate a bit of energy (heat). So just how many amps does the trafficator draw?
http://uk.rs-online.com/web/search/searchBrowseAction.html?method=searchProducts&searchTerm=voltage+regulator+10+amp&x=8&y=8
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1936 Morris 8 Series 1
1973 MGB roadster
1977 MG Midget 1500
Dax Rush
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Uncle Alec



Joined: 14 Jan 2008
Posts: 734
Location: Manchester

PostPosted: Tue Jul 20, 2010 4:57 pm    Post subject: Reply with quote

What a load of buggering about. Get two 12v solenoids if you don't want to simply change the whole unit (which is what I'd do).
I'll send you two reclaimed solenoids if you tell me the model no. of the trafficator (if I have them of course).
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WLC4EVA
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PostPosted: Tue Jul 20, 2010 7:28 pm    Post subject: Reply with quote

.
Have you operated an indicator from an LM338T please Nic?
I ask because I have serious doubts that it would like the voltage spike when 1stpop cancelled a trafficator.

Kind Regards, WLC
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47Jag



Joined: 26 Jun 2008
Posts: 1480
Location: Bothwell, Scotland

PostPosted: Tue Jul 20, 2010 8:58 pm    Post subject: Reply with quote

WLC,

I think there is a flaw in your idea in that I think the solenoid has two windings. Pull-in and holding. The voltage would be that same across the trafficators at 'deployment time', but in the holding mode there would be a higher voltage than 6volts across the working trafficator due to the lower resistance of the 'voltage dropper' which would be always in 'pull-in' made.

Art
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WLC4EVA
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PostPosted: Tue Jul 20, 2010 9:20 pm    Post subject: Reply with quote

.
You could be right 47.

I expect the voltage dropper to be in hold in mode all the time.
Well after the first go anyway.

I felt that if there was a flaw in my suggestion, it was that the operating trafficator wouldn't get enough go-juice.

Uncle Alec's solution is by far the most sensible.
It seems for some reason 1stPop doesn't like it.

My preferred solution is usually to have a 6v sysyem and a 12v system by using 2 batteries.
Makes life a lot simpler.
It can also give the same starting sound.

Kind Regards, WLC
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victor 101



Joined: 03 Apr 2009
Posts: 446
Location: East Yorkshire

PostPosted: Wed Jul 21, 2010 6:33 am    Post subject: Reply with quote

Seems to me if you bought a set of 12v semaphores and sold your 6v you would be no worse of money wise, and it would be safer and quicker to just swap them over.
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Jim.Walker



Joined: 27 Dec 2008
Posts: 1229
Location: Chesterfield

PostPosted: Wed Jul 21, 2010 11:35 am    Post subject: Reply with quote

victor 101 wrote:
Seems to me if you bought a set of 12v semaphores and sold your 6v you would be no worse of money wise, and it would be safer and quicker to just swap them over.


I think you get the prize!!!!!!! This seems like attempts to make "a mountain out of a molehill". Rolling Eyes Rolling Eyes
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Quote from my late Dad:- You only need a woman and a car and you have all the problems you
are ever likely to want". Computers had not been invented then!
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Nic Jarman



Joined: 05 Oct 2008
Posts: 1031
Location: Stoke by Clare, Suffolk

PostPosted: Wed Jul 21, 2010 6:47 pm    Post subject: Reply with quote

WLC, the idea of using a regulator is a fairly standard method in electronics. The regulator would be in circuit before the switch as turning on and off the supply to the regulator is bad practise. Inductive loads must always be treated carefully. Good circuits can be found in "The Art of Electronics" by Horrowizs and Hall, and bad ones to avoid.
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1936 Morris 8 Series 1
1973 MGB roadster
1977 MG Midget 1500
Dax Rush
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WLC4EVA
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PostPosted: Thu Jul 22, 2010 9:23 am    Post subject: Reply with quote

.
Thanks, Nic, very true Nic, I use a number of them for various tasks.

My concern was using the sort of circuit that comes naturally with an LM338T to operate a coil.
An LM338T based regulator circuit would probably be ok for the fuel guage however, assuming it's an electric guage.
However, one of these, http://cgi.ebay.co.uk/LM317-Adjustable-Voltage-Regulator-Prototype-Module-/220466747836?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item3354d799bc would probably be cheaper and easier.

There's also a bit of a wallet problem in a voltage regulator to get 6v starter noises from 6v starter in a 12v system.

Parallel 6v and 12v systems solve the starter challenge, and the other ones, whilst retaining more under-bonnet originality.

Kind Regards, WLC
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