need help fast 6A switch
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From: Virginia
Technically you should not use an AC switch for DC. And the amperage of the load will determine the size of the switch.
DC switches are specially made to open fast and the contacts move farther apart. The problem with DC is not turning it on, but turning it off. Once DC starts flowing, it wants to keep flowing. AC continuously turns off and goes the other direction, so it's easy to turn it off. But if you have a DC load on a AC switch, there is the chance when you turn it off, the current will keep flowing, jumping the smaller gap on a AC switch. This will mean meltdown of the switch.
This also holds true for fuses. DC fuses are specially made so when they open up, they are able to stop the DC current completely.
What are you hooking up? If it was a very small load that was not critical, you could try the switch, though it may not last. If you are switching a heavy load, the switch should be DC, and should be rated for the load it is switching. Of course this is why DC switches cost more money than AC switches.
DC switches are specially made to open fast and the contacts move farther apart. The problem with DC is not turning it on, but turning it off. Once DC starts flowing, it wants to keep flowing. AC continuously turns off and goes the other direction, so it's easy to turn it off. But if you have a DC load on a AC switch, there is the chance when you turn it off, the current will keep flowing, jumping the smaller gap on a AC switch. This will mean meltdown of the switch.
This also holds true for fuses. DC fuses are specially made so when they open up, they are able to stop the DC current completely.
What are you hooking up? If it was a very small load that was not critical, you could try the switch, though it may not last. If you are switching a heavy load, the switch should be DC, and should be rated for the load it is switching. Of course this is why DC switches cost more money than AC switches.
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Laughing Gas
Joined: Jan 2004
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From: Prince George, BC
i forgot to mention that the switch is a toggle switch so i can turn it on and off myself, i am using the toggle switch to lock my torque converter and run an LED light, i bought a DPDT toggle switch that says it is rated 6A 125VAC, and that is printed on the switch, it also says on the switch 3A 250VAC. so will it still work?
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From: Virginia
No matter if you turn it on and off by hand, there is the chance it will not turn the 12 volt DC current off. But you have a fairly light load there, so you could try it and see if it lasts. If it won't cut off, the truck will stall at a stop light because the torque convertor is still in lock-up. All you are switching is a small solenoid in the tranny.
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Laughing Gas
Joined: Jan 2004
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From: Prince George, BC
i am not sure what exactly happens, if there is a solnoid or what, all i know is that when i flick the switch on it grounds out the wire going to the tranny causing the t/c to lock. i think it does something to the PCM. well maybe i should find a different switch, i was at radio shack today, i guess i will go back and see if i can fins a different switch. if i found a bigger rating of switch, say like 10A would that be ok with AC?
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From: Virginia
Radio Shack used have DC rated switches. And they had the 12v light built into them. But they are selling less and less electrical equipment, and more cell phones, so I don't know if they still carry any or not.
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Laughing Gas
Joined: Jan 2004
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From: Prince George, BC
i will go and check, maybe while i am out i will check out and automotive store, i want to make sure i get the right switch. so if i find one it should be rated 12v or more and DC right? how many Amps would i need if i cand find a 12v one? thanks for all your help, i really appreciate it!!
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Laughing Gas
Joined: Jan 2004
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From: Prince George, BC
well i cant find the right switchall of them are AC, i found a couple at radio shack that were DC but there were on/off/on switches, then i went to and electronics store and they showed me acouple of switches and they said VAC on them too, and the dude behind the counter said it was DC, so i have no idea. right now i have a toggle switch that i bought and all the package said was 20A 12V automotive toggle switch, and that one is hooked up rightnow, but i cant put the LED on there cause it isnt a DPDT. i guess i should have gotten a standard transmission truck.
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From: Virginia
but i cant put the LED on there cause it isnt a DPDT
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Laughing Gas
Joined: Jan 2004
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From: Prince George, BC
i ran a positive power right from the battery for that illuminated switch i tried earlier, could i hook the postive on the LED to that and then the ground to the tranny side of the single pole or would this not work ( or is that what you just said but in different words??)
the LED i have is pre wired with a resistor built in
the LED i have is pre wired with a resistor built in
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From: Virginia
You could, but I was staying on the side of caution by running the LED off a switched source in case it was left on accidently.
Also if you wire it up to the battery +, and when you turn everything off, check to see if the LED is glowing dimly. If it is, what is happening is the LED ground has been lost by turning the switch off, but it might find a new ground by going up backwards through the tranny solenoid, and then to the 12 volt circuit that feeds the tranny solenoid. It may run up through some other components and find enough of a ground to glow very dim. This would nothurt anything, but I would not like it myself.
Also if you wire it up to the battery +, and when you turn everything off, check to see if the LED is glowing dimly. If it is, what is happening is the LED ground has been lost by turning the switch off, but it might find a new ground by going up backwards through the tranny solenoid, and then to the 12 volt circuit that feeds the tranny solenoid. It may run up through some other components and find enough of a ground to glow very dim. This would nothurt anything, but I would not like it myself.
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Laughing Gas
Joined: Jan 2004
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From: Prince George, BC
ok thanks franklin2, i cant thank you enough for the help you have given me. i think i will tap into the power i have running to my volt gauge cause i found a fuse where the power was switched on that.