Electrical Progress
- Discovered "RC" circuit is not quick enough to power the huge Contactor relay. Probably because the Relay has an "Economizer" circuit in it, I believe the relay is expecting a "Switch" type jolt of power. Actually, probably banking on this in order to draw down the relay contacts.
- Tried other kinds of RC circuit modifications. None successful.
So then decided to use 555 Timer (because it gives a sharp signal). - Lots, and lots of stuffing around.
- Eventually figured it out, and got it to work perfectly !
Also ... solved the low voltage power problem (ie 12 volts). Simple Zener diode as power supply, with a series of small (low watt) resistors to "share the load". - This is effective at the higher voltage, and gives a nice stable 12V power supply for the 555 and for the relay. Effectively, it is a very rough regulator, or "pre-regulator" ... except there is no need to use an actual regulator to get smoother power (555 is robust).
Tested, and re-tested. - Then re-drew the PCB (yet again) to include the extra components.
Final Schematic
Final PCB (printed to "Print-n-Peel" PCB paper)
