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Odd Behavior of Circuit

BobK

Jan 5, 2010
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Assuming that those are the leads coming out of the bell, that is not the correct connection for the diode. The diode must be directly across the electromagnet coil in the bell. The way you have it wired, the diode is out of the circuit when the interrupter disconnects the magnet and the EMF pulse is created.

Bob
 

ADavis53

Nov 17, 2017
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Nov 17, 2017
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Assuming that those are the leads coming out of the bell, that is not the correct connection for the diode. The diode must be directly across the electromagnet coil in the bell. The way you have it wired, the diode is out of the circuit when the interrupter disconnects the magnet and the EMF pulse is created.

Bob

Thanks, Bob. It may be time for me to throw in the towel on this one. I'm not sure i'll be able to install the diode inside the bell itself given my skill set.


And for Mr. Fixit- Thank you too! I have put the bell on it's own power supply. In all cases i get 12V with no load, 12V with the bell connected and ringing and 12V when the bell stops ringing- i see no variation in voltage under any condition I've tested.

I spoke to the manufacturer of the timer/relay and he too believes that the bell is generating so much hash that it's causing the timer to constantly reset. He also suggested decoupling the power supply.

The bell is an old Archer 49-498a.. .i cannot find any documentation on it anywhere. Not surprising given it's 30-40 years old.

The bell works as intended on its own power supply. rings when it has power, stops as soon as I remove voltage.

If i give the bell constant power via it's own power supply how can my timer/relay impact when it is supposed to ring? Essentially wire the relay/timer backwards and allow it to complete the (-) leg of the circuit when it's closed?
 

Alec_t

Jul 7, 2015
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Try connecting a fat cap, say at least 100uF electrolytic (correctly polarised), 25V rated, in parallel with a 100nF ceramic cap, across the bell terminals.
 

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