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#1
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Define "Normally Open" vs. "Normally Closed"
I'm replacing a broken surface mount magnetic switch mounted on my
garage door that controls a signal light in the house that comes on when the door is open. Thus, I need a switch that is OPEN (meaning no current flows) when the magnet is near the switch and CLOSED (meaning current flows) when the magnet is removed from the switch. So do I need a normally open switch or a normally closed one? Different manufacturers/vendors seem to use the terms differently. Is it "normal" when the magnet is near the switch-- or away from it? |
#2
Posted to alt.home.repair
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Define "Normally Open" vs. "Normally Closed"
Wiki didn't have the answer to this, so I provided it.
http://wiki.answers.com/Q/What_is_th...BhbnN3ZXJzIQ== In switch language, open means to disconnect, or break the circuit. Some people call this "turned off". Closed, is to connect, or make the circuit. Some people call this turned on. In the case of a normally open switch, the switch is open (off) unless something takes action on the switch. Pushes a button for example, or holds a magnet near the switch, or other active force. A normally closed switch is closed (on) unless some force causes the switch to be opened. -- Christopher A. Young Learn more about Jesus www.lds.org .. "Bitzer" wrote in message ... I'm replacing a broken surface mount magnetic switch mounted on my garage door that controls a signal light in the house that comes on when the door is open. Thus, I need a switch that is OPEN (meaning no current flows) when the magnet is near the switch and CLOSED (meaning current flows) when the magnet is removed from the switch. So do I need a normally open switch or a normally closed one? Different manufacturers/vendors seem to use the terms differently. Is it "normal" when the magnet is near the switch-- or away from it? |
#3
Posted to alt.home.repair
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Define "Normally Open" vs. "Normally Closed"
Normal is when the magnet is away. Which is the unactivated
condition. When the magnet is near the reed switch, that's not considered normal -- it's considered activated. -- Christopher A. Young Learn more about Jesus www.lds.org .. "Bitzer" wrote in message ... I'm replacing a broken surface mount magnetic switch mounted on my garage door that controls a signal light in the house that comes on when the door is open. Thus, I need a switch that is OPEN (meaning no current flows) when the magnet is near the switch and CLOSED (meaning current flows) when the magnet is removed from the switch. So do I need a normally open switch or a normally closed one? Different manufacturers/vendors seem to use the terms differently. Is it "normal" when the magnet is near the switch-- or away from it? |
#4
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Define "Normally Open" vs. "Normally Closed"
"Stormin Mormon" wrote in message ... Normal is when the magnet is away. Which is the unactivated condition. When the magnet is near the reed switch, that's not considered normal -- it's considered activated. -- Christopher A. Young Learn more about Jesus www.lds.org . Your description is about as clear as mud. Try again! |
#5
Posted to alt.home.repair
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Define "Normally Open" vs. "Normally Closed"
"Bitzer" wrote in message ... I'm replacing a broken surface mount magnetic switch mounted on my garage door that controls a signal light in the house that comes on when the door is open. Thus, I need a switch that is OPEN (meaning no current flows) when the magnet is near the switch and CLOSED (meaning current flows) when the magnet is removed from the switch. So do I need a normally open switch or a normally closed one? Different manufacturers/vendors seem to use the terms differently. Is it "normal" when the magnet is near the switch-- or away from it? Forget current flows or doesn't flow--that is confusing. Instead, do you have to close the switch in order to turn on the light? If so, then you need a normally open switch. Conversely, if the switch is open when the light is on, then you need a normally closed switch. From what you describe, I would think that you need a normally open switch---light off when door is closed. MLD |
#6
Posted to alt.home.repair
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Define "Normally Open" vs. "Normally Closed"
"MLD" wrote in message
... "Bitzer" wrote in message ... I'm replacing a broken surface mount magnetic switch mounted on my garage door that controls a signal light in the house that comes on when the door is open. Thus, I need a switch that is OPEN (meaning no current flows) when the magnet is near the switch and CLOSED (meaning current flows) when the magnet is removed from the switch. So do I need a normally open switch or a normally closed one? Different manufacturers/vendors seem to use the terms differently. Is it "normal" when the magnet is near the switch-- or away from it? Forget current flows or doesn't flow--that is confusing. Instead, do you have to close the switch in order to turn on the light? If so, then you need a normally open switch. Conversely, if the switch is open when the light is on, then you need a normally closed switch. From what you describe, I would think that you need a normally open switch---light off when door is closed. MLD Actually, not correct, either in analogy or in answer. The answer is normally closed -- as others have said, the state with no outside force acting on it. Same thing with relays -- IF the relay is "single throw". If the relay is "double throw", then again, NO or NC doesn't apply, as both states can be wired in as normal. A toggle light switch also has two "normal" states, even tho it single throw -- because the "outside force" is, well, you, so there is no natural "return position".. Ditto with any rotary-type multi-position switch, for fan speeds, etc.: every position is normal. To the OP, curious as to where you would get this kind of switch -- oem, from the garage door mfr?? How much $$?? Wouldn't they be able to just supply the right part, or are you kluging your own solution? Remarkably, Stormin brought up a good point semantically: "closed" in switching has the opposite meaning to a valve, ito flow. Go figger -- both the semantic snafu, and that Stormin actually grokked it. -- EA |
#7
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Define "Normally Open" vs. "Normally Closed"
Existential Angst wrote:
"MLD" wrote in message ... "Bitzer" wrote in message ... I'm replacing a broken surface mount magnetic switch mounted on my garage door that controls a signal light in the house that comes on when the door is open. Thus, I need a switch that is OPEN (meaning no current flows) when the magnet is near the switch and CLOSED (meaning current flows) when the magnet is removed from the switch. So do I need a normally open switch or a normally closed one? Different manufacturers/vendors seem to use the terms differently. Is it "normal" when the magnet is near the switch-- or away from it? Forget current flows or doesn't flow--that is confusing. Instead, do you have to close the switch in order to turn on the light? If so, then you need a normally open switch. Conversely, if the switch is open when the light is on, then you need a normally closed switch. From what you describe, I would think that you need a normally open switch---light off when door is closed. MLD Actually, not correct, either in analogy or in answer. The answer is normally closed -- as others have said, the state with no outside force acting on it. Same thing with relays -- IF the relay is "single throw". If the relay is "double throw", then again, NO or NC doesn't apply, as both states can be wired in as normal. A toggle light switch also has two "normal" states, even tho it single throw -- because the "outside force" is, well, you, so there is no natural "return position".. Ditto with any rotary-type multi-position switch, for fan speeds, etc.: every position is normal. To the OP, curious as to where you would get this kind of switch -- oem, from the garage door mfr?? How much $$?? Wouldn't they be able to just supply the right part, or are you kluging your own solution? Remarkably, Stormin brought up a good point semantically: "closed" in switching has the opposite meaning to a valve, ito flow. Go figger -- both the semantic snafu, and that Stormin actually grokked it. I bought the switch for about two bucks 15-20 years ago at Radio Shack-- along with the wire, transformer and LED indicator light i needed for my custome designed system. A contractor bashed the existing switch so I've been to a few Radio Shack stores around town but the clerks didn't know wht I was talking about. I showed the broken one to one clerk who thought it was a doorbell. RS seems to mainly sell cell phones and electronic toys these days-- no more electronic components. I see lots of them on line and on Ebay for around $10 or so-- but it's really unclear if they will keep the circuit open when the magnet is near or away. I guess I'll just buy one of each kind-- an NO and an NC-- and toss the one I don't need. |
#8
Posted to alt.home.repair
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Define "Normally Open" vs. "Normally Closed"
"Bitzer" wrote in message
... Existential Angst wrote: "MLD" wrote in message ... "Bitzer" wrote in message ... I'm replacing a broken surface mount magnetic switch mounted on my garage door that controls a signal light in the house that comes on when the door is open. Thus, I need a switch that is OPEN (meaning no current flows) when the magnet is near the switch and CLOSED (meaning current flows) when the magnet is removed from the switch. So do I need a normally open switch or a normally closed one? Different manufacturers/vendors seem to use the terms differently. Is it "normal" when the magnet is near the switch-- or away from it? Forget current flows or doesn't flow--that is confusing. Instead, do you have to close the switch in order to turn on the light? If so, then you need a normally open switch. Conversely, if the switch is open when the light is on, then you need a normally closed switch. From what you describe, I would think that you need a normally open switch---light off when door is closed. MLD Actually, not correct, either in analogy or in answer. The answer is normally closed -- as others have said, the state with no outside force acting on it. Same thing with relays -- IF the relay is "single throw". If the relay is "double throw", then again, NO or NC doesn't apply, as both states can be wired in as normal. A toggle light switch also has two "normal" states, even tho it single throw -- because the "outside force" is, well, you, so there is no natural "return position".. Ditto with any rotary-type multi-position switch, for fan speeds, etc.: every position is normal. To the OP, curious as to where you would get this kind of switch -- oem, from the garage door mfr?? How much $$?? Wouldn't they be able to just supply the right part, or are you kluging your own solution? Remarkably, Stormin brought up a good point semantically: "closed" in switching has the opposite meaning to a valve, ito flow. Go figger -- both the semantic snafu, and that Stormin actually grokked it. I bought the switch for about two bucks 15-20 years ago at Radio Shack-- along with the wire, transformer and LED indicator light i needed for my custome designed system. A contractor bashed the existing switch so I've been to a few Radio Shack stores around town but the clerks didn't know wht I was talking about. I showed the broken one to one clerk who thought it was a doorbell. RS seems to mainly sell cell phones and electronic toys these days-- no more electronic components. I see lots of them on line and on Ebay for around $10 or so-- but it's really unclear if they will keep the circuit open when the magnet is near or away. I guess I'll just buy one of each kind-- an NO and an NC-- and toss the one I don't need. Radio shack ain't what it used to be. Oh, you know, these magnetic switches were common in the old alarms systems, that you would put on doors, windows, etc. -- EA |
#9
Posted to alt.home.repair
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Define "Normally Open" vs. "Normally Closed"
"Bitzer" wrote in message
... Existential Angst wrote: "MLD" wrote in message ... "Bitzer" wrote in message ... I'm replacing a broken surface mount magnetic switch mounted on my garage door that controls a signal light in the house that comes on when the door is open. Thus, I need a switch that is OPEN (meaning no current flows) when the magnet is near the switch and CLOSED (meaning current flows) when the magnet is removed from the switch. So do I need a normally open switch or a normally closed one? Different manufacturers/vendors seem to use the terms differently. Is it "normal" when the magnet is near the switch-- or away from it? Forget current flows or doesn't flow--that is confusing. Instead, do you have to close the switch in order to turn on the light? If so, then you need a normally open switch. Conversely, if the switch is open when the light is on, then you need a normally closed switch. From what you describe, I would think that you need a normally open switch---light off when door is closed. MLD Actually, not correct, either in analogy or in answer. The answer is normally closed -- as others have said, the state with no outside force acting on it. Same thing with relays -- IF the relay is "single throw". If the relay is "double throw", then again, NO or NC doesn't apply, as both states can be wired in as normal. A toggle light switch also has two "normal" states, even tho it single throw -- because the "outside force" is, well, you, so there is no natural "return position".. Ditto with any rotary-type multi-position switch, for fan speeds, etc.: every position is normal. To the OP, curious as to where you would get this kind of switch -- oem, from the garage door mfr?? How much $$?? Wouldn't they be able to just supply the right part, or are you kluging your own solution? Remarkably, Stormin brought up a good point semantically: "closed" in switching has the opposite meaning to a valve, ito flow. Go figger -- both the semantic snafu, and that Stormin actually grokked it. I bought the switch for about two bucks 15-20 years ago at Radio Shack-- along with the wire, transformer and LED indicator light i needed for my custome designed system. A contractor bashed the existing switch so I've been to a few Radio Shack stores around town but the clerks didn't know wht I was talking about. I showed the broken one to one clerk who thought it was a doorbell. RS seems to mainly sell cell phones and electronic toys these days-- no more electronic components. I see lots of them on line and on Ebay for around $10 or so-- but it's really unclear if they will keep the circuit open when the magnet is near or away. I guess I'll just buy one of each kind-- an NO and an NC-- and toss the one I don't need. If you find one that says SPDT or DPDT, then it can be used as either NC or NO. Often, the screw terminals or lugs themselves are labeled NO and NC, but not the switch as a whole. -- EA |
#10
Posted to alt.home.repair
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Define "Normally Open" vs. "Normally Closed"
On Apr 29, 11:56*am, Bitzer wrote:
Existential Angst wrote: "MLD" wrote in message ... "Bitzer" wrote in message ... I'm replacing a broken surface mount magnetic switch mounted on my garage door that controls a signal light in the house that comes on when the door is open. Thus, I need a switch that is OPEN (meaning no current flows) when the magnet is near the switch and CLOSED (meaning current flows) when the magnet is removed from the switch. So do I need a normally open switch or a normally closed one? Different manufacturers/vendors seem to use the terms differently. Is it "normal" when the magnet is near the switch-- or away from it? Forget current flows or doesn't flow--that is confusing. *Instead, do you have to close the switch in order to turn on the light? *If so, then you need a normally open switch. *Conversely, if the switch is open when the light is on, then you need a normally closed switch. *From what you describe, I would think that you need a normally open switch---light off when door is closed. MLD Actually, not correct, either in analogy or in answer. The answer is normally closed -- as others have said, the state with no outside force acting on it. Same thing with relays -- IF the relay is "single throw". If the relay is "double throw", then again, NO or NC doesn't apply, as both states can be wired in as normal. A toggle light switch also has two "normal" states, even tho it single throw -- because the "outside force" is, well, you, so there is no natural "return position".. Ditto with any rotary-type multi-position switch, for fan speeds, etc.: every position is normal. To the OP, curious as to where you would get this kind of switch -- oem, from the garage door mfr?? How much $$?? *Wouldn't they be able to just supply the right part, or are you kluging your own solution? Remarkably, Stormin brought up a good point semantically: *"closed" in switching has the opposite meaning to a valve, ito flow. *Go figger -- both the semantic snafu, and that Stormin actually grokked it. I bought the switch for about two bucks 15-20 years ago at Radio Shack-- along with the wire, transformer and LED indicator light i needed for my custome designed system. A contractor bashed the existing switch so I've been to a few Radio Shack stores around town but the clerks didn't know wht I was talking about. I showed the broken one to one clerk who thought it was a doorbell. RS seems to mainly sell cell phones and electronic toys these days-- no more electronic components. I see lots of them on line and on Ebay for around $10 or *so-- but it's really unclear if they will keep the circuit open when the magnet is near or away. I guess I'll just buy one of each kind-- an NO and an NC-- and toss the one I don't need.- Hide quoted text - - Show quoted text - "Radio Shack seems to mainly sell cell phones and electronic toys these days-- no more electronic components." Well, since you brought it up... I was working at an event this weekend and somebody broke the 1/4 mono jack for one of the loudspeakers. I went over to the nearest Radio Shack to get a new jack. Since the young lady was nice enough to approach me and ask if she could help, I started to explain to her what I needed - quickly noticing the glaze that was coming over her eyes. Her response was "You'll have to speak to one of those guys. I know a lot about cell phones, but not much about that kind of stuff." So what's the deal? Does Radio Shack *expect* that everyone that walks into the store wants a cell phone? If not, why would someone who knows nothing about their other products approach me? |
#11
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Define "Normally Open" vs. "Normally Closed"
On Thu, 29 Apr 2010 13:49:12 -0700 (PDT), DerbyDad03
wrote: On Apr 29, 11:56*am, Bitzer wrote: Existential Angst wrote: "MLD" wrote in message ... "Bitzer" wrote in message ... I'm replacing a broken surface mount magnetic switch mounted on my garage door that controls a signal light in the house that comes on when the door is open. Thus, I need a switch that is OPEN (meaning no current flows) when the magnet is near the switch and CLOSED (meaning current flows) when the magnet is removed from the switch. So do I need a normally open switch or a normally closed one? Different manufacturers/vendors seem to use the terms differently. Is it "normal" when the magnet is near the switch-- or away from it? Forget current flows or doesn't flow--that is confusing. *Instead, do you have to close the switch in order to turn on the light? *If so, then you need a normally open switch. *Conversely, if the switch is open when the light is on, then you need a normally closed switch. *From what you describe, I would think that you need a normally open switch---light off when door is closed. MLD Actually, not correct, either in analogy or in answer. The answer is normally closed -- as others have said, the state with no outside force acting on it. Same thing with relays -- IF the relay is "single throw". If the relay is "double throw", then again, NO or NC doesn't apply, as both states can be wired in as normal. A toggle light switch also has two "normal" states, even tho it single throw -- because the "outside force" is, well, you, so there is no natural "return position".. Ditto with any rotary-type multi-position switch, for fan speeds, etc.: every position is normal. To the OP, curious as to where you would get this kind of switch -- oem, from the garage door mfr?? How much $$?? *Wouldn't they be able to just supply the right part, or are you kluging your own solution? Remarkably, Stormin brought up a good point semantically: *"closed" in switching has the opposite meaning to a valve, ito flow. *Go figger -- both the semantic snafu, and that Stormin actually grokked it. I bought the switch for about two bucks 15-20 years ago at Radio Shack-- along with the wire, transformer and LED indicator light i needed for my custome designed system. A contractor bashed the existing switch so I've been to a few Radio Shack stores around town but the clerks didn't know wht I was talking about. I showed the broken one to one clerk who thought it was a doorbell. RS seems to mainly sell cell phones and electronic toys these days-- no more electronic components. I see lots of them on line and on Ebay for around $10 or *so-- but it's really unclear if they will keep the circuit open when the magnet is near or away. I guess I'll just buy one of each kind-- an NO and an NC-- and toss the one I don't need.- Hide quoted text - - Show quoted text - "Radio Shack seems to mainly sell cell phones and electronic toys these days-- no more electronic components." Well, since you brought it up... I was working at an event this weekend and somebody broke the 1/4 mono jack for one of the loudspeakers. I went over to the nearest Radio Shack to get a new jack. Since the young lady was nice enough to approach me and ask if she could help, I started to explain to her what I needed - quickly noticing the glaze that was coming over her eyes. Her response was "You'll have to speak to one of those guys. I know a lot about cell phones, but not much about that kind of stuff." So what's the deal? Does Radio Shack *expect* that everyone that walks into the store wants a cell phone? If not, why would someone who knows nothing about their other products approach me? Radio Shack should expect everyone to buy a cellphone. They left me with a bad taste in my mouth when I bought my first compute from them. I used to buy everything at Radio Shack. I can't remember the last time I have been in one of their stores. Several years. I know your situation was that you needed something that day. I let Newegg bring the stuff to my door. |
#12
Posted to alt.home.repair
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Define "Normally Open" vs. "Normally Closed"
On Thu, 29 Apr 2010 11:56:39 -0400, Bitzer wrote:
Existential Angst wrote: "MLD" wrote in message ... "Bitzer" wrote in message ... I'm replacing a broken surface mount magnetic switch mounted on my garage door that controls a signal light in the house that comes on when the door is open. Thus, I need a switch that is OPEN (meaning no current flows) when the magnet is near the switch and CLOSED (meaning current flows) when the magnet is removed from the switch. So do I need a normally open switch or a normally closed one? Different manufacturers/vendors seem to use the terms differently. Is it "normal" when the magnet is near the switch-- or away from it? Forget current flows or doesn't flow--that is confusing. Instead, do you have to close the switch in order to turn on the light? If so, then you need a normally open switch. Conversely, if the switch is open when the light is on, then you need a normally closed switch. From what you describe, I would think that you need a normally open switch---light off when door is closed. MLD Actually, not correct, either in analogy or in answer. The answer is normally closed -- as others have said, the state with no outside force acting on it. Same thing with relays -- IF the relay is "single throw". If the relay is "double throw", then again, NO or NC doesn't apply, as both states can be wired in as normal. A toggle light switch also has two "normal" states, even tho it single throw -- because the "outside force" is, well, you, so there is no natural "return position".. Ditto with any rotary-type multi-position switch, for fan speeds, etc.: every position is normal. To the OP, curious as to where you would get this kind of switch -- oem, from the garage door mfr?? How much $$?? Wouldn't they be able to just supply the right part, or are you kluging your own solution? Remarkably, Stormin brought up a good point semantically: "closed" in switching has the opposite meaning to a valve, ito flow. Go figger -- both the semantic snafu, and that Stormin actually grokked it. I bought the switch for about two bucks 15-20 years ago at Radio Shack-- along with the wire, transformer and LED indicator light i needed for my custome designed system. A contractor bashed the existing switch so I've been to a few Radio Shack stores around town but the clerks didn't know wht I was talking about. I showed the broken one to one clerk who thought it was a doorbell. RS seems to mainly sell cell phones and electronic toys these days-- no more electronic components. I see lots of them on line and on Ebay for around $10 or so-- but it's really unclear if they will keep the circuit open when the magnet is near or away. I guess I'll just buy one of each kind-- an NO and an NC-- and toss the one I don't need. Go to the Borg or any other reasonably well stocked shop and get a normally closed magnetic alarm switch. Install it so the magnet (on the door) is in proximity to the switch with the door closed, and the light will come on when the magnet leaves the switch. |
#13
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Define "Normally Open" vs. "Normally Closed"
On Apr 29, 9:07*am, Bitzer wrote:
I'm replacing a broken surface mount magnetic switch mounted on my garage door that controls a signal light in the house that comes on when the door is open. Thus, I need a switch that is OPEN (meaning no current flows) when the magnet is near the switch and CLOSED (meaning current flows) when the magnet is removed from the switch. So do I need a normally open switch or a normally closed one? Different manufacturers/vendors seem to use the terms differently. Is it "normal" when the magnet is near the switch-- or away from it? You need a NC switch as you describe it. |
#14
Posted to alt.home.repair
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Define "Normally Open" vs. "Normally Closed"
On Thu, 29 Apr 2010 09:32:45 -0700 (PDT), Bob Villa
wrote: On Apr 29, 9:07*am, Bitzer wrote: I'm replacing a broken surface mount magnetic switch mounted on my garage door that controls a signal light in the house that comes on when the door is open. Thus, I need a switch that is OPEN (meaning no current flows) when the magnet is near the switch and CLOSED (meaning current flows) when the magnet is removed from the switch. So do I need a normally open switch or a normally closed one? Different manufacturers/vendors seem to use the terms differently. Is it "normal" when the magnet is near the switch-- or away from it? You need a NC switch as you describe it. Normally = Energized = most of the time. Except fire alarm systems Upload the wiring diagram to be sure. |
#15
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Define "Normally Open" vs. "Normally Closed"
"Metspitzer" wrote in message
news On Thu, 29 Apr 2010 09:32:45 -0700 (PDT), Bob Villa wrote: On Apr 29, 9:07 am, Bitzer wrote: I'm replacing a broken surface mount magnetic switch mounted on my garage door that controls a signal light in the house that comes on when the door is open. Thus, I need a switch that is OPEN (meaning no current flows) when the magnet is near the switch and CLOSED (meaning current flows) when the magnet is removed from the switch. So do I need a normally open switch or a normally closed one? Different manufacturers/vendors seem to use the terms differently. Is it "normal" when the magnet is near the switch-- or away from it? You need a NC switch as you describe it. Normally = Energized = most of the time. Not in relays. -- EA Except fire alarm systems Upload the wiring diagram to be sure. |
#16
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Define "Normally Open" vs. "Normally Closed"
On Thu, 29 Apr 2010 13:29:25 -0400, "Existential Angst"
wrote: "Metspitzer" wrote in message news On Thu, 29 Apr 2010 09:32:45 -0700 (PDT), Bob Villa wrote: On Apr 29, 9:07 am, Bitzer wrote: I'm replacing a broken surface mount magnetic switch mounted on my garage door that controls a signal light in the house that comes on when the door is open. Thus, I need a switch that is OPEN (meaning no current flows) when the magnet is near the switch and CLOSED (meaning current flows) when the magnet is removed from the switch. So do I need a normally open switch or a normally closed one? Different manufacturers/vendors seem to use the terms differently. Is it "normal" when the magnet is near the switch-- or away from it? You need a NC switch as you describe it. Normally = Energized = most of the time. Not in relays. I meant De energized in motor relays and Energized in fire alarm systems. |
#17
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Define "Normally Open" vs. "Normally Closed"
On Thu, 29 Apr 2010 13:07:44 -0400, Metspitzer
wrote: On Thu, 29 Apr 2010 09:32:45 -0700 (PDT), Bob Villa wrote: On Apr 29, 9:07Â*am, Bitzer wrote: I'm replacing a broken surface mount magnetic switch mounted on my garage door that controls a signal light in the house that comes on when the door is open. Thus, I need a switch that is OPEN (meaning no current flows) when the magnet is near the switch and CLOSED (meaning current flows) when the magnet is removed from the switch. So do I need a normally open switch or a normally closed one? Different manufacturers/vendors seem to use the terms differently. Is it "normal" when the magnet is near the switch-- or away from it? You need a NC switch as you describe it. Normally = Energized = most of the time. Except fire alarm systems Upload the wiring diagram to be sure. Actually, even with fire alarms you can have series string (normally closed) or parallel string(normally open) circuits. |
#18
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Define "Normally Open" vs. "Normally Closed"
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#19
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Define "Normally Open" vs. "Normally Closed"
On Thu, 29 Apr 2010 10:07:15 -0400, Bitzer wrote:
I'm replacing a broken surface mount magnetic switch mounted on my garage door that controls a signal light in the house that comes on when the door is open. Thus, I need a switch that is OPEN (meaning no current flows) when the magnet is near the switch and CLOSED (meaning current flows) when the magnet is removed from the switch. So do I need a normally open switch or a normally closed one? Different manufacturers/vendors seem to use the terms differently. Is it "normal" when the magnet is near the switch-- or away from it? Or you can look at the switch you pulled out and wire the new one the same way. |
#20
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Define "Normally Open" vs. "Normally Closed"
"Bitzer" wrote in message ... I'm replacing a broken surface mount magnetic switch mounted on my garage door that controls a signal light in the house that comes on when the door is open. Thus, I need a switch that is OPEN (meaning no current flows) when the magnet is near the switch and CLOSED (meaning current flows) when the magnet is removed from the switch. So do I need a normally open switch or a normally closed one? Different manufacturers/vendors seem to use the terms differently. Is it "normal" when the magnet is near the switch-- or away from it? As an electrician, I've been through this numerous times over the years. It clearly depend on who you are talking to, and what trade they're in. IMO, the "normal" position is the state the switch is in when nothing affects it. Alarm people have the opposite take on it. My solution is to always buy devices that come in the "form C" which is both open and closed circuits, this way you can't go wrong |
#21
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Define "Normally Open" vs. "Normally Closed"
On Thu, 29 Apr 2010 16:49:51 -0400, "RBM" wrote:
"Bitzer" wrote in message ... I'm replacing a broken surface mount magnetic switch mounted on my garage door that controls a signal light in the house that comes on when the door is open. Thus, I need a switch that is OPEN (meaning no current flows) when the magnet is near the switch and CLOSED (meaning current flows) when the magnet is removed from the switch. So do I need a normally open switch or a normally closed one? Different manufacturers/vendors seem to use the terms differently. Is it "normal" when the magnet is near the switch-- or away from it? As an electrician, I've been through this numerous times over the years. It clearly depend on who you are talking to, and what trade they're in. IMO, the "normal" position is the state the switch is in when nothing affects it. Alarm people have the opposite take on it. My solution is to always buy devices that come in the "form C" which is both open and closed circuits, this way you can't go wrong Yeah, then you can put one wire on the "common" and flip a coin. Wire it NO and if the light goes off when it should come on then wire it NC. My best guess is that you should wire it NO and the magnet will close the switch. |
#22
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Define "Normally Open" vs. "Normally Closed"
On Thu, 29 Apr 2010 17:54:39 -0400, Metspitzer
wrote: On Thu, 29 Apr 2010 16:49:51 -0400, "RBM" wrote: "Bitzer" wrote in message ... I'm replacing a broken surface mount magnetic switch mounted on my garage door that controls a signal light in the house that comes on when the door is open. Thus, I need a switch that is OPEN (meaning no current flows) when the magnet is near the switch and CLOSED (meaning current flows) when the magnet is removed from the switch. So do I need a normally open switch or a normally closed one? Different manufacturers/vendors seem to use the terms differently. Is it "normal" when the magnet is near the switch-- or away from it? As an electrician, I've been through this numerous times over the years. It clearly depend on who you are talking to, and what trade they're in. IMO, the "normal" position is the state the switch is in when nothing affects it. Alarm people have the opposite take on it. My solution is to always buy devices that come in the "form C" which is both open and closed circuits, this way you can't go wrong Yeah, then you can put one wire on the "common" and flip a coin. Wire it NO and if the light goes off when it should come on then wire it NC. My best guess is that you should wire it NO and the magnet will close the switch. That's fine if he wants to know when the door is CLOSED - Generally people set it up that they know when it is OPEN. (or NOT closed) |
#23
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Define "Normally Open" vs. "Normally Closed"
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#24
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Define "Normally Open" vs. "Normally Closed"
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#25
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Define "Normally Open" vs. "Normally Closed"
RBM wrote:
"Bitzer" wrote in message ... I'm replacing a broken surface mount magnetic switch mounted on my garage door that controls a signal light in the house that comes on when the door is open. Thus, I need a switch that is OPEN (meaning no current flows) when the magnet is near the switch and CLOSED (meaning current flows) when the magnet is removed from the switch. So do I need a normally open switch or a normally closed one? Different manufacturers/vendors seem to use the terms differently. Is it "normal" when the magnet is near the switch-- or away from it? As an electrician, I've been through this numerous times over the years. It clearly depend on who you are talking to, and what trade they're in. IMO, the "normal" position is the state the switch is in when nothing affects it. Alarm people have the opposite take on it. My solution is to always buy devices that come in the "form C" which is both open and closed circuits, this way you can't go wrong He he he, most electricians I come across are befuddled by three way and four way switches. I had to explain it to my electrical superintendent and foreman on a government job I worked on some years ago. Normally open and normally closed had to be explained to them using the illustration of the difference between a virtuous woman and a slut. *snicker* TDD |
#26
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Define "Normally Open" vs. "Normally Closed"
RBM wrote:
"Bitzer" wrote in message ... I'm replacing a broken surface mount magnetic switch mounted on my garage door that controls a signal light in the house that comes on when the door is open. Thus, I need a switch that is OPEN (meaning no current flows) when the magnet is near the switch and CLOSED (meaning current flows) when the magnet is removed from the switch. So do I need a normally open switch or a normally closed one? Different manufacturers/vendors seem to use the terms differently. Is it "normal" when the magnet is near the switch-- or away from it? As an electrician, I've been through this numerous times over the years. It clearly depend on who you are talking to, and what trade they're in. IMO, the "normal" position is the state the switch is in when nothing affects it. Alarm people have the opposite take on it. I agree. In all the following the contacts are closed with the magnet next to the reed switch. From an alarm perspective *NC* ("normal" is when the door is closed): http://en.wikipedia.org/wiki/Burglar..._control_panel "Most switching devices are N.C. (normally closed) circuits, so when the device is not in an alarm condition, the circuit is closed." http://www.alibaba.com/product-gs/21...ch_5C_31A.html "Output signal: normally closed (switch contact is closed when the door closed)" From a component manufacturer *NO* C&K: "ELECTRICAL CIRCUIT: SPST NO (Contact Form A). Reed switch opens when magnet is removed from proximity. Contacts are held closed when magnet is within actuation range." To know what the switch does you need to have a description like all of the above. My solution is to always buy devices that come in the "form C" which is both open and closed circuits, this way you can't go wrong For the magnetic switches I looked at from alarm companies, none said NO or NC. A few said NC loop. They were probably all "NC" from an alarm perspective. Except a few were Form C. -- bud-- |
#27
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Define "Normally Open" vs. "Normally Closed"
On Apr 29, 9:07*am, Bitzer wrote:
I'm replacing a broken surface mount magnetic switch mounted on my garage door that controls a signal light in the house that comes on when the door is open. Thus, I need a switch that is OPEN (meaning no current flows) when the magnet is near the switch and CLOSED (meaning current flows) when the magnet is removed from the switch. So do I need a normally open switch or a normally closed one? Different manufacturers/vendors seem to use the terms differently. Is it "normal" when the magnet is near the switch-- or away from it? You use a reed switch, with TWO magnets. When the door is down, place the two magnets so they oppose each other, the reed switch will stay open if you position the magnets correctly. one magnet on the door, one on the frame next to the reed relay/switch. When the door goes up, the one magnet will move away from the reed relay/switch and the remaining magnet will close the switch and turn on your alarm/light bulb/whatever. This is high-school 9th grade stuff, not rocket science!!!! |
#28
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Define "Normally Open" vs. "Normally Closed"
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#29
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Define "Normally Open" vs. "Normally Closed"
"Bitzer" wrote in message ... I'm replacing a broken surface mount magnetic switch mounted on my garage door that controls a signal light in the house that comes on when the door is open. Thus, I need a switch that is OPEN (meaning no current flows) when the magnet is near the switch and CLOSED (meaning current flows) when the magnet is removed from the switch. So do I need a normally open switch or a normally closed one? Different manufacturers/vendors seem to use the terms differently. Is it "normal" when the magnet is near the switch-- or away from it? NC -- Nonny On most days, it's just not worth the effort of chewing through the restraints.. |
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