meeotch
Newbie level 5
I'm going to be controlling several (15 or so) solenoids using an arduino, and I'd like to protect them from getting stuck in the energized position - e.g., if the arduino crashes or something shorts out. I can't do it with a single fuse on the power supply, since there's no telling how many may be on at any given time & thus the total current is unpredictable. I could fuse them individually, but I'm trying to avoid that to save space/time/cost. Also, it's difficult to size the fuses, because the inrush current is much higher than the steady-state current when the coils activate. (The coils may pull a couple of amps each when first activated, but only one amp when held in the on position.)
Is there some sort of alternative device or circuit that will act like a slow-blow fuse? That is, one that will react to the *time* that coil has been energized, rather than only the amount of current going through it?
I thought some sort of R-C circuit might do the trick, but these are AC coils, and my head exploded when attempting to puzzle it out.
Power source is a 120V to 24VAC transformer, and the coils are the only things drawing from it. So the ideal solution would be one that sits next to the transformer, and cuts the circuit if it draws 1A for more than, say, 30 seconds - but will not react to a draw of 10A for less than a few seconds.
Is there some sort of alternative device or circuit that will act like a slow-blow fuse? That is, one that will react to the *time* that coil has been energized, rather than only the amount of current going through it?
I thought some sort of R-C circuit might do the trick, but these are AC coils, and my head exploded when attempting to puzzle it out.
Power source is a 120V to 24VAC transformer, and the coils are the only things drawing from it. So the ideal solution would be one that sits next to the transformer, and cuts the circuit if it draws 1A for more than, say, 30 seconds - but will not react to a draw of 10A for less than a few seconds.