Can you get a device to alter motor speed like the TRV alters water flow?

[ericmark]

I have a old Myson radiator, this has it's own thermostat switching it on/off as required and a manual speed control, my late mother-in-law caught the speed control with her wheel chair and broke off the control knob, it is quite a hefty resistor so just set at a medium speed.

However just like the TRV alters flow rate according to temperature so giving a seamless control, I wondered if there is now a control to alter fan speed according to temperature? Two reasons, one is better temperature control and the second is to reduce noise.

On a cold day we really need to heat pumped out by the Myson, we simply could not fit a standard radiator in that location, but on warmer days having it stopped or just ticking over would make watching TV so much easier, we would not need to turn up the volume.

But before trying to replace the broken part, it seems a good idea to see if there is not a better model.

 

[Alec_t]

I wondered if there is now a control to alter fan speed according to temperature?

Yes. It's commonplace in computers and automobiles. Easy with DC motors; difficulty varies with type of AC motors.

 

[Roger928]

Yes its simple...

The Components needed :

1. Arduino
2. Temperature Sensor LM35
3. 1K Resistor
4. Diode 1N4007
5. Dc Motor or a simple DC fan
6. NPN transistor BC547
7. A voltage source with 12Volts
8. hook up wires
9. optional : voltage source socket

 

[magicmushroom666]

You could use a basic mechanical thermostat to stop and start the fan when the temperature changes.

Depending on the type of fan it may be possible to completely control the speed using a PID controller and SCR but that's probably over complicating things!

 

[ericmark]

I had considered on/off or more to point pulse width modulated, however to get an off the shelf unit would be a better option. I would have thought by now there is a ready built unit, there must be loads of people who have swapped from an old on/off boiler to a modern condensate boiler which has variable flame height, and so also need to change the radiator on/off to a variable speed control to match.

If I have to build my own I would think start point is a lamp dimming unit, and build from that, but expect some where there is a ready built unit designed for retro fit?