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-   -   Anyone see a problem with this definition of Normally Open? (http://www.diychatroom.com/f17/anyone-see-problem-definition-normally-open-116225/)

justplumducky 09-04-2011 09:56 PM

Anyone see a problem with this definition of Normally Open?
 
Normally Open-
State where current flows until the plunger pin is actuated to close the electrical circuit.

Found this definition in an online EPA certification practice test site. Anyone see a problem with it, or is it just me?

JJboy 09-04-2011 10:02 PM

NC - Normally Close
NO - Normally Open

Original state when doesn't have power voltage applied.

justplumducky 09-04-2011 10:07 PM

Thx for your reply JJBoy

What I was getting at:
Quote:

Normally Open-
State where current flows until the plunger pin is actuated to close the electrical circuit.
Seems to me this is saying that current flows in an open circuit. Since when does current flow in an OPEN circuit?

JJboy 09-04-2011 10:14 PM

It isn't clear, but may be the voltage of the coil

gregzoll 09-05-2011 02:20 AM

Quote:

Originally Posted by justplumducky (Post 721284)
Thx for your reply JJBoy

What I was getting at:

Seems to me this is saying that current flows in an open circuit. Since when does current flow in an OPEN circuit?

When does traffic flow along a city street? When does water flow out along water pipes and out of your faucet or garden house? When does pedestrian flow downtown a busy metropolis along sidewalks?

justplumducky 09-05-2011 06:10 AM

Quote:

Originally Posted by gregzoll (Post 721343)
When does traffic flow along a city street? When does water flow out along water pipes and out of your faucet or garden house? When does pedestrian flow downtown a busy metropolis along sidewalks?

Thx for your reply Greg~, but I have no clue what you're talking about - can't tell if you agree or disagree with my statement "Since when does current flow in an open circuit?"

beenthere 09-05-2011 07:22 AM

The practical definition of an open circuit. is no flow.

So it should read: State where no current flows until the plunger pin is actuated to close the electrical circuit.

justplumducky 09-05-2011 08:56 AM

Thank you beenthere.

gregzoll 09-05-2011 09:55 AM

Quote:

Originally Posted by justplumducky (Post 721410)
Thx for your reply Greg~, but I have no clue what you're talking about - can't tell if you agree or disagree with my statement "Since when does current flow in an open circuit?"

The point that I was trying to prove, is to think about your question that you posted, to figure out the answer about what is Normally Closed, and What is Normally Open.

justplumducky 09-05-2011 10:12 AM

Quote:

The point that I was trying to prove, is to think about your question that you posted, to figure out the answer about what is Normally Closed, and What is Normally Open.
I already knew the answer from a purely electrical point of view, but when I brought it to the attention of the aforementioned EPA Practice Testing site, he told me his definition was correct. That got me wondering if there wasn't some sort of application in HVAC/R where maybe the usual electrical definition didn't apply. Then I got to realizing that electrical symbols (and their definitions) would probably have to be universal, thus my statement, "Since when does current flow in a normally OPEN circuit?"

Sorry for being a bit obtuse and missing your meaning Greg~.

beenthere 09-05-2011 10:33 AM

As with going to seminars. The people that write test, often interject their own personal interpretations. And thats what it sounds like the guy did that wrote the test you saw/took.

gregzoll 09-05-2011 10:38 AM

Don't worry. When I went to Basic Electricity & Electronics for the Navy, they had their way of stating things, that was different than how my father taught me about stuff. Then of course, it all changed when you actually got to do the work at your duty station. The process changed along with the way of doing things, but the way things worked in a circuit didn't.


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