[DeTomaso] Hot Dimmer Switch

[Tomas Gunnarsson]

Your in house dimmer is not a rheostat (which is basically an adjustable resistor), it's a thyristor controller and works in a pulse width modulating mode that's much more efficient.

Tomas

----- Original Message ----- 
From: "Art Stephens" <artstephens at charter.net>
To: "Ken Green" <kenn_green at yahoo.com>; "Thomas Tornblom" <Thomas.Tornblom at hax.se>; "Tomas Gunnarsson" <guson at home.se>
Cc: <detomaso at realbig.com>
Sent: den 20 mars 2007 18:39
Subject: Re: [DeTomaso] Hot Dimmer Switch


Ken,
     I think you may be on to something here.  I believe the dimmer 
originally did not control the lights to the speedo and tach?  I'm thinking 
the later cars had a second dimmer to handle that?  My new speedo and tach 
have two bright lights apiece that my dimmer did not have to handle before. 
After testing,  I can see that one bulb per unit will be plenty,  if that 
isn't good enough,  I'll probably pull the bulb out of the light that covers 
the gauges and climate controls.  It just doesn't seem like that giant 
rheostat should get that hot?  I've got a 300 watt halogen lamp in the 
living room and the rheostat never gets that hot and it is handling like 20 
times the juice?
Thanks,

Art


----- Original Message ----- 
From: "Ken Green" <kenn_green at yahoo.com>
To: "Thomas Tornblom" <Thomas.Tornblom at hax.se>; "Tomas Gunnarsson" 
<guson at home.se>
Cc: "Art Stephens" <artstephens at charter.net>; <detomaso at realbig.com>
Sent: Monday, March 19, 2007 1:26 PM
Subject: Re: [DeTomaso] Hot Dimmer Switch


>      You can make a very efficient switched capacitor or switched inductor 
> power supply, but the ones I have seen don't have a knob to vary the 
> voltage out.  I guess there are really cheap processors available and I 
> suppose some may have inputs for a pot and they can be programmed to 
> control a switched power supply and thereby control the voltage output 
> based on the pot setting.  Seems like overkill?
>
>        If the lights are too bright, maybe try dimmer (lower current) 
> bulbs first, and see if that drops the power dispated in the dimmer switch 
> enough?  The heat you're feeling should just be proportional to the sum of 
> the currents through all of the light it is controlling.
>
>  Ken
>
> Thomas Tornblom <Thomas.Tornblom at hax.se> wrote:
>  Tomas Gunnarsson skrev:
>> Art,
>>
>> There is no efficiency gain to be had by switching from one rheostat ot 
>> another. They all have the same power loss at a given output voltage.
>
> Unless one use some modern switching thing.
>
>>
>> Tomas
>
> Thomas
>
>>
>> ----- Original Message ----- 
>> From: "Art Stephens"
>> To:
>> Sent: den 19 mars 2007 07:45
>> Subject: [DeTomaso] Hot Dimmer Switch
>>
>>
>>> I ran for years with no dimmer switch for the gauges. After installing 
>>> the new AutoMeter speedo and tach, I hooked up the dimmer switch again 
>>> because the new units were so bright. Now that dimmer runs hot. It gets 
>>> so hot that I'm pretty sure if given enough time, the bezel will be too 
>>> hot to touch. My main concern here is fire. Has anyone out there 
>>> replaced their rheostat with something a little more efficient?
>>>
>>> Art
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>
>
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