special solenoid valve

HotWaterWizard is on the right track. Use your master arm switch to control the coil of a SPDT automotive relay. Tie Pin 30 to 12vdc Pin 87 will go to a constant to momentary relay (like above) with the output being the "enable coil" of the valve Pin 87A will go to a second constant to momentary relay with the output being the "disable coil" of the valve When you turn the switch on it will energize the relay which will send a constant voltage out pin 87. This constant voltage will get changed in to a pulse. When you turn the switch off, the relay will drop out, providing constant voltage on pin 87A. This constant voltage will get changed in to a pulse as well.Kevin Pierson

Kevin,

I think I understand your concept. It would be easier to visualize if it was drawn out. Any chance you could create a diagram showing what you are describing? It would be much appreciated. The mfg of the solenoid valve states that relays are not necessary due to needing only a monentary low current 12V to trigger the valve ON and OFF and the valve does not require any current to maintain either valve state. Seems like relays in the circuit would be overkill unless they are vital to creating the momentary pulsed 12v. Is there an easier way to do this? 

Thanks!

Kevin,

I think I got it. When I put it on paper it now makes sense.

Master arming switch drives a SPDT master relay. Term 87 of the master relay drives constant to momentary relay # 1 for momentary ON signal to valve. When the master switch is OFF, term 87A of the master relay drives constant to momentary relay #2 for momentary OFF signal to valve.

Seems complicated but it should work. It still seems like since I don't need any current to maintain the valve position that this could be done an easier way. What do you think?

Thanks

I will try again with another Idea I have along the same line.

OKAY Why do we need a relay at all? a SPST Switch is it (ON/ON)

John DeRosa (Hotwaterwizard)

Stockton California

When in doubt, try it out !

The arming switch (ON/OFF) is already existing and I need to do everything with just one switch. The 1st drawing with the relay would work especially when there is no power from the switch in the OFF position. Relay 87A solves that problem. Will the resistor/cap combo change a constant into a pulse? If so for how long of a pulse? I probably need about a second.

Thanks

That is the purpose of the resistor and Capacitor. To change it into a pulse. 

For a longer pulse just add another capacitor across the other in parallel  

John DeRosa (Hotwaterwizard)

Stockton California

When in doubt, try it out !

I do not think that the 10K resistor will provide enough current to operate the solenoid.

Good question . I asummed it was simular to the Relay coil amp draw. the Capacitor actually powers the coil and the resistor drains the voltage down at a given rate depending on its value.

Imagine the capacitor as a battery.

John DeRosa (Hotwaterwizard)

Stockton California

When in doubt, try it out !

If the capacitor was paralleled across the Motor, it would make a pulse last longer. No DC voltage will go through the capacitor. The only voltage to get to the Motor will be the voltage allowed through the resistor.

Different Circuit application.

http://www.electronics-tutorials.ws/rc/rc_1.html

http://www.play-hookey.com/ac_theory/ac_rc_parallel.html

http://www.wolframalpha.com/entities/calculators/parallel_RC_circuit/fc/08/36/

John DeRosa (Hotwaterwizard)

Stockton California

When in doubt, try it out !