Real life dilemma: Help powering an AC device with DC

[BobK]

I would check what happens when you press the button. Do you get 12V AC between the 2 wires at the chime? If you, you cannot simply connect that to your chime.

Bob

 

[BGB]

An AC inductive device relies on the inductive reactance to limit current, if fed from DC the load is purely the resistance of the coil, which is very low for a AC device.
Usually it is not a good idea, even if the voltage is lowered.
The AC device current is determined by the inductive reactance effectively in series with the DC resistance.
M.

yeah, could be.

the contactor coils have resistances of around 7 and 12 ohms IIRC. probably not meant to pull a lot of current as they use fairly thin wire. one looks like 28 AWG, the other maybe 30 AWG (and uses a physically smaller coil). one will close at 5v, and the other closes at 7v.

could be useful if I want to drive them using PWM off of a 12v battery though (to drive a few DC motors, they should be sufficient. the peak power for the motors is at least below the LRA for the contractors, though the efficiency point of the motors is above the FLA for the contactors, but it may be ok as they have a lot of metal and I would be running them at a fairly low voltage. ).