D.C. Grd Detect Lights

[group44]

I need to provide a set of lights, and a test pushbutton for a 125VDC 2 wire system. One light for Pos to Grd and the other for Neg to Grd. The pushbutton would light both for a test. Spec only calls out lights w/ resistors, or LED. Does anyone have a wiring diagram and info on how to size the resistor? Any help would be greatly appreciated

 

[itsmoked]

Use a "break b4 make" double-pole/double-throw pushbutton.

The "unpushed" normally closed contacts hook the bulbs up in their non-test form. When you push the button they are disconnected from their normal form and hooked to the test setup.

But then your question has so little detail I'm probably being foolish.



Keith Cress
kcress -

http://www.flaminsystems.com

 

[waross]

The old ground detector circuit would just be two lights connected line to ground. In normal operation both lights light at less than full brilliance. If one line goes to ground, that lamp goes out and the other goes to full brilliance. No test switch needed.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[rovineye]

Below is how the Navy does it. Look at 300-3.2.6.2.2 and the associated schematic.

 

[Skogsgurra]

That's a rather interesting document, rovineye.

It seems to have been around for a while. And still not quite correct. Picture B is a three-phase AC system. But the text says DC system. Surely someone must have spotted this before?

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...

 

[group44]

Rovineye,

Thank you very much. I knew there had to be a design out there. This is exactly what I was looking for.

Gary

 

[rovineye]

Skogsgurra,
Yes that is an error. I have used that as guidance before, when adding capacitors to a ground detector, and never noticed the mis-label. There is a method for reporting such errors. I tried it once and next thing I knew I was tasked with verifying the entire document. I won't make that mistake again.

This document that I posted excerpts from has about 350 pages.

 

[Skogsgurra]

I refrain from it, too!

Gunnar Englund

http://www.gke.org

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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...