Is a relay required to run a purge solinoid?
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From: Alexandria La.
Is a relay required to run a purge solinoid? About ready to wire up the purge noid, bought my kit used so I have no Idea if it requires a relay or not. I was kinda figuring since my line lock requires no relay that the purge probably wouldnt either but I didnt want to start a fire under my hood because I didnt ask someone that knew. 
Most do not, including NOS, Cold Fusion and I think Dyno Tune? The nos type is not a constant voltage type so no worry (momentary on/off). Cold Fusion is a constant voltage, but a very small amp load 1 1/2 or 2 amps. So both can be wired with out relay. Now I have run both types, but I chose to use a relay, just seems a little safer, imo. It's a judgement call on your part.
Robert
Robert
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From: Alexandria La.
Originally Posted by Robert56
Most do not, including NOS, Cold Fusion and I think Dyno Tune? The nos type is not a constant voltage type so no worry (momentary on/off). Cold Fusion is a constant voltage, but a very small amp load 1 1/2 or 2 amps. So both can be wired with out relay. Now I have run both types, but I chose to use a relay, just seems a little safer, imo. It's a judgement call on your part.
Robert
Robert
Thanks for the reply!
Originally Posted by WS6HUMMER
Guess I'll give it a try without a relay, I'll run and inline 2.5 amp fuse though.
Thanks for the reply!
Thanks for the reply!
Robert
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From: LT1 land...the "409" of the 90s!
Most do not have a relay as Robert has typed up for you. I still insist on installing them. I can not count how many times for some strange reason they burn out the switchs 
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From: Wichita Falls, TX
I would go with a relay, just for the convience of using small gauge wire to controll the noid.. And you can run a lesser switch since very little amps are running throu it.
Ricky
Ricky
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From: Alexandria La.
Originally Posted by NXRICKY
I would go with a relay, just for the convience of using small gauge wire to controll the noid.. And you can run a lesser switch since very little amps are running throu it.
Ricky
Ricky
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I doubt there will be an initial surge. That's backward
from how an inductor behaves. What will kill your
cheapo switch is the arc on opening circuit, the
inductor current -will- still circulate as long as it's
able, and throw an arc during break. A poor quality
contact won't take much of that without pitting.
An automotive relay expects to drive inductive loads
and is made to survive it.
from how an inductor behaves. What will kill your
cheapo switch is the arc on opening circuit, the
inductor current -will- still circulate as long as it's
able, and throw an arc during break. A poor quality
contact won't take much of that without pitting.
An automotive relay expects to drive inductive loads
and is made to survive it.
Originally Posted by jimmyblue
I doubt there will be an initial surge. That's backward
from how an inductor behaves. What will kill your
cheapo switch is the arc on opening circuit, the
inductor current -will- still circulate as long as it's
able, and throw an arc during break. A poor quality
contact won't take much of that without pitting.
An automotive relay expects to drive inductive loads
and is made to survive it.
from how an inductor behaves. What will kill your
cheapo switch is the arc on opening circuit, the
inductor current -will- still circulate as long as it's
able, and throw an arc during break. A poor quality
contact won't take much of that without pitting.
An automotive relay expects to drive inductive loads
and is made to survive it.
Robert
Originally Posted by jimmyblue
I doubt there will be an initial surge. That's backward
from how an inductor behaves. What will kill your
cheapo switch is the arc on opening circuit, the
inductor current -will- still circulate as long as it's
able, and throw an arc during break. A poor quality
contact won't take much of that without pitting.
An automotive relay expects to drive inductive loads
and is made to survive it.
from how an inductor behaves. What will kill your
cheapo switch is the arc on opening circuit, the
inductor current -will- still circulate as long as it's
able, and throw an arc during break. A poor quality
contact won't take much of that without pitting.
An automotive relay expects to drive inductive loads
and is made to survive it.
So the next obvious question is what amp relay?
Guessing a 10-20?
My dry kit on the little brown truck...Thanks Dean!
While making the panels, I came across a new switch from Edelbrock for momentary applications, look way more HD than the Radioshack ones I have been using for the mock up (and about 7 times more expensive too). Gonna order one of them for my purge. #72274
Cheers
Beer
Guessing a 10-20?
My dry kit on the little brown truck
...Thanks Dean!While making the panels, I came across a new switch from Edelbrock for momentary applications, look way more HD than the Radioshack ones I have been using for the mock up (and about 7 times more expensive too). Gonna order one of them for my purge. #72274
Cheers
Beer
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From: Wichita Falls, TX
Originally Posted by Beer99C5
So the next obvious question is what amp relay?
Guessing a 10-20?
My dry kit on the little brown truck...Thanks Dean!
While making the panels, I came across a new switch from Edelbrock for momentary applications, look way more HD than the Radioshack ones I have been using for the mock up (and about 7 times more expensive too). Gonna order one of them for my purge. #72274
Cheers
Beer
Guessing a 10-20?
My dry kit on the little brown truck
...Thanks Dean!While making the panels, I came across a new switch from Edelbrock for momentary applications, look way more HD than the Radioshack ones I have been using for the mock up (and about 7 times more expensive too). Gonna order one of them for my purge. #72274
Cheers
Beer
Several things to look at. If the switch is rated at the amp draw you are using you are good to go, with one thing to think about. The size of the wire needed to run.. Most relays are used to keep the heavy gauge stuff from running in and all around the car.
Ricky
Capacitive loads draw a current spike on close-
circuit. So would a stalled-rotor motor (relative
to running steady current) where the winding
current has no back-EMF to oppose the voltage.
But the motor is not entirely like an inductor
(solenoid). An inductor current will be zero at
the instant of close-circuit and ramp up until
you hit the winding resistance limit. In a motor
you'd have the current start at zero, ramp up
fairly quick (inductor) and then come back down
as the much slower rotor spins up and starts
pushing back voltage against the supply. A
motor will minimize winding resistance to allow
maximum torque (current) while a solenoid is
usually designed with internal limiting resistance
to permit "stalled" steady state operation.
I wouldn't worry much about ratings, everything
on the AutoZone shelf is 30A, seems like.
circuit. So would a stalled-rotor motor (relative
to running steady current) where the winding
current has no back-EMF to oppose the voltage.
But the motor is not entirely like an inductor
(solenoid). An inductor current will be zero at
the instant of close-circuit and ramp up until
you hit the winding resistance limit. In a motor
you'd have the current start at zero, ramp up
fairly quick (inductor) and then come back down
as the much slower rotor spins up and starts
pushing back voltage against the supply. A
motor will minimize winding resistance to allow
maximum torque (current) while a solenoid is
usually designed with internal limiting resistance
to permit "stalled" steady state operation.
I wouldn't worry much about ratings, everything
on the AutoZone shelf is 30A, seems like.
