momentary to constant setup problem

Ok I understand this is supposed to work, but I can't get it to. Nor do I understand how it works. Call me an idiot but hey I still can't figure it out. The setup I'm referring to is this one. 

I'm using a momentary push button for the pulse. I've checked the wiring a dozen times, it all checks out. But it only stays on as long as I have the button pushed. When I stopped the analyze the circuit, I my mind that's what it should do. Not stay on till ground or source is broken.

The way my feeble mind reads it is,

- pulse on 1st relay to pin #86 energizes the coil closing the switch between pin #30 & #87                                                                                                                                            Pin #87 from 1st relay energizes the 2nd relay at pin #85 closing the switch between pin #30 & #87.   (a redundant operation)                                                                           What I don't understand is what keeps the coil on the second relay energized? If you remove the - ground from pin #86 on the 1st relay, the field collapse opening the switch between #30 & #87. This in turn would turn off the 2nd relay because there is no longer a + connection to the coil on pin #85.                                                                        Yes No, am I full of something, or just plain stupid?

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Only the strong survive.
Eat the weak.

On the right relay, notice that 85 is also connected to 87, once that relay is energized, 87 keeps 12 volts on 85, thus keeping it energized.  Build it, it will work.  I think the diode is needed to eliminate relay chatter.

K

So one of my relay's must be wanky.

-------------
Only the strong survive.
Eat the weak.

Here is an easier circuit diagram

494_latching_relay_2.gif

Here is another that you just remove power to unlatch the circuit.

Here is the same circuit with a Cube relay

Here is a diagram of what the numbers mean.


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John DeRosa (Hotwaterwizard)
Stockton California
When in doubt, try it out !