An old 2C/GPO mains powered telephone bell outdoor repeater/sounder. To be used outdoors as a portable flooding-imminent alarm , in the theory that no one these takes notice of car alarm or house alarm piezo sounders these days. Quite easy to take apart, 2 stators 150 ohms each and armature 34 ohms across the commutator, all in series for 240V ac. Placing all 3 in parallel instead, starts and turns reliably unloaded at
12V Dc, not reassembled with the sounder diaphragm yet . The klaxon sounder is the same mechanism used in percussion mode of a hand power drill. Hopefully when the sounder diaphragm is replaced, it will start and run loud enough on 18V battery pack, failing that adding another 12V battery in series. The rear thrust bearing of the rotor shaft has a lockable but easy to adjust mechanism to change the pressure of the percussion sawtooth ratchet wheel against the pip of the diaphragm of the sounder (labelled as tuning) so perhaps allow to spin up no load then engage load and so noise generation, repeatedly, if the DC voltage is not enough for continuous sounding loudly. It looks like the stator coils are only wedged in by thin phenolic board, so perhaps easily removed and potentially replaced with winding of coils of thicker wire , retaining the rotor as is, and get more noise possibly. Any other ideas to make more noise if necessary?- posted
1 month ago