ICM254 Fan Blower Control Delay Timer -How to convert it to 12V DC

Thread Starter

Manfred Von Steinborn

Joined Feb 3, 2009
38
Thanks,
It is obvious that this timer module is powered by AC and can witch AC on and of.
Also, it is obvious that the PCB works on DC internally, ICs /transistors don't work on AC well. I'd like to find the way to power it with DC, that's all.
 

t06afre

Joined May 11, 2009
5,934
Thanks,
It is obvious that this timer module is powered by AC and can witch AC on and of.
Also, it is obvious that the PCB works on DC internally, ICs /transistors don't work on AC well. I'd like to find the way to power it with DC, that's all.
Both right and wrong. As said before I am 99.9% sure that the component controlling the output. Is a component that will need AC to work as wanted. The setup you want can for sure be done with some 555 timers. Why are you so stubborn about this:confused:
 

#12

Joined Nov 30, 2010
18,210
It absolutely, positively, uses a triac and depends on AC pulses to charge the delay capacitors. I know because I've taken that one (and several others) apart and traced out the circuits. Great place for ideas about using jfets for delay timers, but not how to use DC on a triac.

If you trace out the circuit with a pencil and paper, you might learn how to modify it, but it is going to be a very different circuit that you end up with.
 

CDRIVE

Joined Jul 1, 2008
2,219
Second opinion, please...

Anyone?
There isn't enough components on your board to have us believe there's any zero crossing detection. Therefore the Triac is probably triggered on the lower ends of the pos & neg slopes of the AC cycles.

DC brush motors generate electrical hash where the brushes make contact with the commutator. This hash is both positive and negative in nature. This is a very long shot but I'm wondering if replacing the Triac with an SCR, would work. When the timer has timed out, the gate trigger voltage is probably removed. I'm wondering if an SCR would turn off due to the negative hash voltage between the anode and cathode? Has anyone ever tested this?

The most you could loose is the cost of the SCR and even that won't be a loss because if it doesn't work you could build a 555 circuit that will employ the SCR.
 
Top