Power Control Kemo M028N

[Roy Proud]

Hi, hoping someone out there can help. I am using a Kemo M028 Power controller. It is possible to replace the potentiometer with control voltages (1-5V/DC or 3-12V/DC or 6-24V/DC) What I would like to do find is a digital timing circuit that could raise the voltage at a pre determined time for eg raise from 1-5V/DC anywhere between 10mins and 60 mins. Ideally it would have a digital display. Sounds simple, but I just cannot find such a device.

Thanks Roy

 

[rjenkinsgb]

The whole controller is "live" to the AC power and AC is passed through the external pot circuit, so it's not safe to connect the existing control wires to separate electronics, without some form of isolation - opto or relay etc.

The module manufacturers do make a matching isolated unit specifically for the type of application you need:

M150 DC + pulse converter

www.kemo-electronic.de

The next simplest option would be use eg. two or three potentiometers in series, and have relays to short out some of them - relays open give the lowest speed, relays closed the highest speed & some closed/open intermediate speeds.

Or you could use a digital timer module that had an AC mains rated output contact, to short out the "low speed" pot after a set amount of time?

 

[Nigel Goodwin]

While not impossible, it's likely to be fairly difficult, and would need the existing schematic to work it out.

So it's certainly NOT simple, which is why you can't find such a device.

It looks like a crude triac/thyristor circuit, so the pot will be fully live to the mains as well.