Heater fan

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Re: Heater fan

Postby fozzza » Sat Jan 02, 2016 7:02 pm

benofbrum wrote:I used one of those Rover resistor units and mounted it on the side of the battery box with the plastic mounting uppermost and open on the sides. When I went to the classic car show at the Bath and West showground, the demister was on all the way down from Birmingham on the middle or low speed with no problems. Remember, even on the lower settings, most of the power will still be dissipated in the heater motor and at full power, no current goes through the resistors.

Thanks for the prompt feedback and advice, eBay hear I come, you must agree having the one speed fan is a bit primitive and while I'm sorting the electrics and got the heater and dash out I might as well try and upgrade it.

cheers.
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Re: Heater fan

Postby Inim666 » Sun Jan 03, 2016 12:37 am

I am currently trying to work out why the mini mpi heater won't fit correctly in the gap where the single speed unit used to sit.
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Re: Heater fan

Postby benofbrum » Sun Jan 03, 2016 11:23 am

The heater motor is only a single speed unit. The speed reductions are obtained via the resistor pack. You will also need the appropriate switch, which has to carry the full motor current at max speed. On Citroen BX's which I have owned in the past, the fan speed was controlled by a rheostat (variable resistor) which varied the control current to a power transistor which then fed the motor. These control units became quite rare.
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Re: Heater fan

Postby fozzza » Sun Jan 03, 2016 12:34 pm

benofbrum wrote:The heater motor is only a single speed unit. The speed reductions are obtained via the resistor pack. You will also need the appropriate switch, which has to carry the full motor current at max speed. On Citroen BX's which I have owned in the past, the fan speed was controlled by a rheostat (variable resistor) which varied the control current to a power transistor which then fed the motor. These control units became quite rare.

On the Car builder solutions website they do sell a fan speed conversion switch but it costs £30 and it is a rotary switch. I will use off/on/on heater rocker switch repositioned on the dash and the rover resistor and wire it accordingly to give me about half speed and bypass it to give me full speed.
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Re: Heater fan

Postby Geoff Butcher » Sun Jan 03, 2016 8:54 pm

fozzza wrote:
benofbrum wrote:
On the Car builder solutions website they do sell a fan speed conversion switch but it costs £30 and it is a rotary switchI will use off/on/on heater rocker switch repositioned on the dash and the rover resistor and wire it accordingly to give me about half speed and bypass it to give me full speed.


Just like a Morris Minor! I've got one of those if anyone wants it. (Switch, that is, not a Minor)
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Re: Heater fan

Postby fozzza » Mon Jan 04, 2016 1:24 am

Geoff Butcher wrote:
fozzza wrote:
benofbrum wrote:
On the Car builder solutions website they do sell a fan speed conversion switch but it costs £30 and it is a rotary switchI will use off/on/on heater rocker switch repositioned on the dash and the rover resistor and wire it accordingly to give me about half speed and bypass it to give me full speed.


Just like a Morris Minor! I've got one of those if anyone wants it. (Switch, that is, not a Minor)


I'm sorted but thank you for the offer.

kind regards.

Roy
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