On 05/06/2019 09:55, Harry Bloomfield wrote:
It happens that Harry Bloomfield formulated :
My bathroom extract fan's wax actuator has failed. This is used to
slowly open the shutters, when the fan is triggered. This one..

https://www.ebay.co.uk/itm/223481092415?ul_noapp=true

It looks as if it has over-heated in the area, before it actually
failed. As it is marked 120/240v I'm thinking to install a dropper to
reduce the voltage across it to around 120v, but I cannot find a
specification for the wattage or current to determine a suitable dropper.

Anyone know please?

I've just had another idea - a 400v diode will reduce the consumption to
around 50%, without the extra heat dissipation of a resistor.

Just trying to extend the working life of the actuator.

Good idea, but 400V doesn't give much margin on 240V RMS - go for a
1N4007 1kV diode. This used to be a trick for keeping a
non-thermostatic soldering iron on standby, you put a diode in a torpedo
switch.

(Although the motor does say .02A which would make it ~5W @ 240V.)

Cheers
--
Clive