quote:

Originally posted by 67TSCHEVY2:
a solenoid has to have power to make or break the electrical connection. power has to be ran to a switch i assume in the drivers compartment. a electrical disconnect does not cut the power off to the control switch or the solenoid could not be energized. read the rulebook.... This cutoff switch must be connected to the positive side of the electrical system and must stop all electrical functions...

Are you commenting on my set up or the link?

The last sentence is straight out of the Nhra rulebook , make out of it what you wish lol ...

quote:

Originally posted by 67TSCHEVY2:
The last sentence is straight out of the Nhra rulebook , make out of it what you wish lol ...

Really strange response to a simple question but okay.

I make nothing of it because you are making wrong assumptions. I totally agree with the last sentence in your comment and have no problem with it because I am entirely legal.

I do have to say though that you are wrong about needing power to break the solenoid connection or you are stating wrong what you mean.

Wrong depends on what type of solenoid one uses. So which one is right .....

quote:

Originally posted by 67TSCHEVY2:
Wrong depends on what type of solenoid one uses. So which one is right .....

Okay I think I see what you are saying now. Why would anyone use a normally closed solenoid and use power to open it to kill the main power? LOL Also why not just ask that? Either way I am legal, safe and it works great. Much to the dismay of some.

So you are using a N.O. solenoid. Can't be but two ways to close it so pick one. Lol

Wouldn't a solenoid that is activated by a switch that needs a ground still have a positive connection as a typical on/off mechanical switch once power is killed?

A mechanical switch doesn't kill the + connection from the battery to the switch, just everything after the switch.So if you had a solenoid that needed a ground to energize the solenoid and power the car, wouldn't it still have the same live cable to the solenoid if the solenoid didn't have a ground input?
Maybe I'm thinking about it wrong, but I don't see a need for a + wire to be wired to the kill switch/es if it needs a ground to complete the circuit to power the car. Remove the ground and car would shut down in my opinion.
Discuss

quote:

Originally posted by 67TSCHEVY2:
So you are using a N.O. solenoid. Can't be but two ways to close it so pick one. Lol

Already did, thanks.

M120,
My two Master Disconnect switches, one on dash nd on on rear valance are wired to complete a ground circuit that opens the solenoid and no power can come out of it. When "on" the solenoid is "engaged" and uses some milliamps as it gets a little warm over a couple hours. I just click it off with dash mounted master Switch when the truck sits. 3 years not even the smallest of issues. easy to wire (18 gauge wire) and low-amp toggle switch is all that is needed.
Jok

Jok, I'm cutting power with my switches. Don't want a grounded wire allowing the activation of the solenoid.

quote:

Originally posted by 67TSCHEVY2:
a solenoid has to have power to make or break the electrical connection. power has to be ran to a switch i assume in the drivers compartment. a electrical disconnect does not cut the power off to the control switch or the solenoid could not be energized. read the rulebook.... This cutoff switch must be connected to the positive side of the electrical system and must stop all electrical functions...

Constant duty solenoids are normally open if wired properly the rear switch (the one NHRA actually cares about) kills power to the entire car including the secondary switch inside the car.

I think I am now reading between the lines here.
1. If you control the solenoid with switches inside the driver area and the back of the vehicle, they must be wired in series so that either switch will kill the power.

2. As Curtis states, he uses the + battery power through those switches because he doesn't want a potential grounded wire to cause the switch to stay on.

3. But the NHRA rule states that the cutoff switch must be connected to the positive side of the electrical system and must stop ALL electrical functions.

4. So if you follow the rule, but have the emergency stop switches wired to provide positive power to the solenoid to send power to ALL electrical functions. Then once the solenoid is turned off, you will never be able to turn it back on because you have killed the positive power to the emergency stop switches that will need power to turn the solenoid (or solid state relay) back on.

5. But if you do use the negative or ground through the emergency stop switches to control the solenoid (or solid state relay), then you will meet the rule as stated and will be able to energize the solenoid (or solid state relay) and restore positive power back to everything in the vehicle.

I think I said that all that correctly.

So you are reading into it that having power to the switch, (potential) is a function? #4

quote:

My two Master Disconnect switches, one on dash nd on on rear valance are wired to complete a ground circuit that opens the solenoid and no power can come out of it. When "on" the solenoid is "engaged" and uses some milliamps as it gets a little warm over a couple hours. I just click it off with dash mounted master Switch when the truck sits. 3 years not even the smallest of issues. easy to wire (18 gauge wire) and low-amp toggle switch is all that is needed.

^^^^^^ NOT LEGAL

8:4 MASTER CUTOFF
Mandatory when battery is relocated, or as outlined in Class
Requirements. An electrical power cutoff switch (one only) must be installed on the rearmost part of each vehicle and be easily accessible from outside the car body. This cutoff switch must be connected to the POSITIVE SIDE of the electrical system and must stop all electrical functions including magneto ignition. The off
position
must be clearly indicated with the word “OFF.” If switch
is “push/pull” type, “push” must be the action for shutting off
the electrical
system, “pull” to turn it on. Any rods or cables
used to activate the switch must be minimum 1/8-inch diameter.
Plastic or keyed switches prohibited. Switches and/or controls
must be located behind rear wheels on rear-engine dragsters.

This message has been edited. Last edited by: markemark,

quote:

If you control the solenoid with switches inside the driver area and the back of the vehicle, they must be wired in series so that either switch will kill the power.

^^^^^NOT LEGAL

8:4 MASTER CUTOFF
Mandatory when battery is relocated, or as outlined in Class
Requirements. An electrical power cutoff switch (ONE ONLY) must
be installed on the rearmost part of each vehicle and be easily
accessible
from outside the car body. This cutoff switch must be
connected to the positive side of the electrical system and must
stop all electrical functions including magneto ignition. The off
position
must be clearly indicated with the word “OFF.” If switch
is “push/pull” type, “push” must be the action for shutting off
the electrical
system, “pull” to turn it on. Any rods or cables
used to activate the switch must be minimum 1/8-inch diameter.
Plastic or keyed switches prohibited. Switches and/or controls
must be located behind rear wheels on rear-engine dragsters.

Thinking that if a tech guy pushes the switch on the back of my car and the car shuts off, the fuel pump and all other 12 volt accessories shut down he could care less how it happened. BTW - I chose the ground wire between the solenoid and a switch at the rear and one on the dash in series method with the rear switch having priority.

This message has been edited. Last edited by: Lincoln,

The solenoid or power relay (solid state) will be connected to and controlling the positive side of the battery feed. If the "emergency stop" switches that control the solenoid or power relay (solid state) use the ground connection to turn on or off the battery positive controlled solenoid or relay (solid state), then that meets the rules.

As far as the "one only" cutoff switch that must be located at the back of the vehicle, there is an awful lot of vehicles that don't fully meet that rule because they ALSO have a manually activated way to operate the battery disconnect switch from within the driver compartment.

This is how I interpret the rule..

The cutoff switch on this car is the “ONLY ONE” and is activated from the outside rear of the car. The rule does NOT say this ONLY ONE cutoff switch cannot be (manually) activated from inside the car.

If you use a N/C push to OPEN contact switch, mounted on the rear exterior of your car, THIS contact switch is NOW the Master Cut Off, NOT the 300 amp relay that the 2 gauge battery cable is attached to. And because the contact switch is the ONLY ONE master cut off, the positive power that goes through it cannot be series with another remotely controlled switch.

The positive power at my master cut off does NOT remove the battery power from my car. It turns OFF my relay board that controls all electrical functions of the car.

Ahhhh Mr West gets it LMAO

Both of my cars will pass a real tech inspection anywhere and have passed an NHRA Tech Inspection at a divisional and national events those with electrical/solenoids will not!