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-   -   E-Stop (http://www.homebrewtalk.com/f170/e-stop-276656/)

Bsquared 10-25-2011 05:31 PM

E-Stop
 
So the last part of my Electric set up I need is the E-Stop. I ordered the big red mushroom, and have an in-line fuse holder for the 1amp fuse, but I am a little stumped on the two 1Ω resistors. The resistors I am picturing are the ones that get soldered in to a board. are these the ones people use? How are these incorporated with a wire? are they just soldered in-line to the wire? or is there a better way.

Thanks in advance for the help.

samc 10-25-2011 06:01 PM

Are you talking about the P-J device? If so I just carefully, soldered a wire on the metal leads.

audger 10-25-2011 06:19 PM

anything that gives you a little resistance will work. for only 1ohm, you can probably even get away without it- though i wont tell you to do that without seeing the whole wiring diagram. i believe all its for is to trickle a little current to the ground wire to trip the GFCI. a standard 1/8th watt resistor with some 28 or 26ga wire will work for that.

do you have a specific wiring diagram to confirm?

Bsquared 10-25-2011 06:58 PM

Yes I'm using PJ wire diagram for the e-stop. This is what I am thinking of...http://lh4.ggpht.com/_eA-8mAKSPic/St...09_32-crop.jpg
Is this right?

orangehero 10-25-2011 11:39 PM

On his diagrams they are 1K ohm 1W.

kellzey 10-26-2011 02:51 AM

Yes, you need something like this... these are 1 watt resistors

http://justradios.com/sscomp.JPG

I think the ones in post #4 or 1/8, 1/4, and 1/2 watt

I picked up from my local electronics surplus place...

Bsquared 10-26-2011 02:55 AM

Sweet,Thanks. I did not see the 1K 1W this morning. I have a good electronic component shop I go to down the street. I'm sure they will have them.

kellzey 10-26-2011 03:08 AM

If you get stuck, i can get some more and send some to you.

lschiavo 10-26-2011 03:16 AM

Using two 1k resistors results in 7 Watts dissipated and 60mA of fault current. I assume the wattage of the resistors doesn't matter much as the Gfi should trip before the resistors have much chance to heat.

I think the fault current could be reduced by raising the resistance and maybe splitting the load into three resistors. Then the wattage rating of the resistors would not be exceeded. Is this worth doing? Wouldn't 15 or 20mA be sufficient to trip the gfi? I think this is a brilliant way to provide an e stop but I never really understood the excessive current or undersized resistors.

P-J 10-26-2011 03:48 AM

Please keep in mind that once the E-Stop is pressed the GFCI will cut all of the power to the control panel within a millisecond. There is no need to have higher wattage resistors or resistors that limit the current draw to a lower level. We are talking about 0.06A for less time that it would take for you to blink your eye. Will the resistors heat up? NOT a chance.!


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