Thanks for the replies. Klaus, i have looked for a datasheet and was not able to find one. This doorbell ringer is circa 1961... the model number doesn't even turn up in a google search. I've ordered a 24V transformer capable of 30A. That seems like an amazing amount of current... I think I charge my electric car with about 11 amps, why on earth you need 30 amps to move a chime striker an inch is beyond me. My thinking is that the solenoid is only seeing current when the doorbell (momentary switch) is depressed. The way most people ring a doorbell, the coil is only in use for a fraction of a second, not enough time to heat up even given its thin gauge wire. Worth a shot, if it doesn't work I'll contact NuTone and see if they can sell me two 24V solenoids. Thanks for your help![/QUOTE
Is your resistance measurement of 51 ohms on your solenoid correct. If it were DC voltage I would expect the current would be less than .50 amp.
24v divided by 51 ohms = .47 amps.