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Reedswitch

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pelletie1959(at)me.com
Guest

Posted: Tue Feb 21, 2017 5:51 pm Post subject: Reedswitch

Hi Bob,



My question. I figure to use your following wiring diagram for my Pitot Heated.

http://www.aeroelectric.com/PPS/DeIce/Pitot_Heat.pdf



I found and ordered the Reed Switch that you recommand on your diagram. The part number 2750232 of Radio schack.



I remark that this switch is for a 5 Volts circuit.

https://www.radioshack.com/products/spst1a-5vreed-rly



I found another Reed switch that seems to fit for a 12 volts circuit. The part number is 2750233

https://www.radioshack.com/products/spst1a-12v-rd-rly



The part number 2750232 is correct or it's better to use the Reedswitch 2750233?



Regards.



Daniel Pelletier

arcticarrow(at)gmail.com
Guest

Posted: Tue Feb 21, 2017 6:49 pm Post subject: Reedswitch

Hi Daniel,



Curious, what’s the function of the reed switch in the pitot heat schematic?



Thanks,

Bernie

 	  Quote: 	
		   On Feb 21, 2017, at 4:46 PM, DANIEL PELLETIER <pelletie1959(at)me.com> wrote:

 

 

 

 Hi Bob,

 

 My question. I figure to use your following wiring diagram for my Pitot Heated.

 http://www.aeroelectric.com/PPS/DeIce/Pitot_Heat.pdf

 

 I found and ordered the Reed Switch that you recommand on your diagram. The part number 2750232 of Radio schack.

 

 I remark that this switch is for a 5 Volts circuit.

 https://www.radioshack.com/products/spst1a-5vreed-rly

 

 I found another Reed switch that seems to fit for a 12 volts circuit. The part number is 2750233

 https://www.radioshack.com/products/spst1a-12v-rd-rly

 

 The part number 2750232 is correct or it's better to use the Reedswitch 2750233?

 

 Regards.

 

 Daniel Pelletier

ceengland7(at)gmail.com
Guest

Posted: Tue Feb 21, 2017 7:30 pm Post subject: Reedswitch

Looks like proof of life for the pitot heater. If the heater circuit or 

heater dies for some reason, the LED goes out.



On 2/21/2017 8:43 PM, Bernie Willis wrote:

 	  Quote: 	
		   



 Hi Daniel,



 Curious, what’s the function of the reed switch in the pitot heat schematic?



 Thanks,

 Bernie

> On Feb 21, 2017, at 4:46 PM, DANIEL PELLETIER <pelletie1959(at)me.com> wrote:

>

> 

>

> Hi Bob,

>

> My question. I figure to use your following wiring diagram for my Pitot Heated.

> http://www.aeroelectric.com/PPS/DeIce/Pitot_Heat.pdf

>

> I found and ordered the Reed Switch that you recommand on your diagram. The part number 2750232 of Radio schack.

>

> I remark that this switch is for a 5 Volts circuit.

> https://www.radioshack.com/products/spst1a-5vreed-rly

>

> I found another Reed switch that seems to fit for a 12 volts circuit. The part number is 2750233

> https://www.radioshack.com/products/spst1a-12v-rd-rly

>

> The part number 2750232 is correct or it's better to use the Reedswitch 2750233?

>

> Regards.

>

> Daniel Pelletier

>

user9253

Joined: 28 Mar 2008
Posts: 1927
Location: Riley TWP Michigan

Posted: Tue Feb 21, 2017 7:33 pm Post subject: Re: Reedswitch

If I am interpreting the schematic correctly, the relay coil is not used.  Therefore it does not matter if the coil is rated for 5 volts or 12 volts.  It is not used.  Instead, you wind your own coil with wire rated to carry the heater current.  The number of turns in the new coil will be determined by trial and error.  Start with 5 turns and keep increasing the number until the reed switch closes.  It is not necessary to purchase a reed relay.  A reed switch is all that is needed.  Reed switches are very inexpensive.  Shipping will cost more than a reed switch.

  The combination of a reed switch wrapped with wire makes a current sensing relay.

_________________
Joe Gores

user9253

Joined: 28 Mar 2008
Posts: 1927
Location: Riley TWP Michigan

Posted: Tue Feb 21, 2017 7:49 pm Post subject: Re: Reedswitch

"Magnet wire" has very thin insulation which makes it better suited for winding coils.  Electric motors are wound with magnet wire.

eBay item number: 251137776873

_________________
Joe Gores

nuckolls.bob(at)aeroelect
Guest

Posted: Wed Feb 22, 2017 12:22 pm Post subject: Reedswitch

At 09:52 PM 2/21/2017, you wrote:

  	  Quote: 	
		  --> AeroElectric-List message posted by: Eric Page <edpav8r(at)yahoo.com>



 The reed switch is sensitive to magnetic fields.  The five turns ("5T" on the diagram) of wire around the switch act as an inductor, creating a magnetic field that will close the switch when the pitot heater is drawing current.  This will turn on the LED indicator without having to directly interrupt the feed to the heater or its control relay. 	


   Correct. See  http://tinyurl.com/htf4elj



 

   Bob . . .

arcticarrow(at)gmail.com
Guest

Posted: Wed Feb 22, 2017 1:36 pm Post subject: Reedswitch

That’s a cleaver idea.  I put an analog ammeter in the circuit for the same reason but not as sophisticated.

Bernie 	  Quote: 	
		  On Feb 22, 2017, at 11:19 AM, Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:

  At 09:52 PM 2/21/2017, you wrote:  	  Quote: 	
		  --> AeroElectric-List message posted by: Eric Page <edpav8r(at)yahoo.com (edpav8r(at)yahoo.com)> The reed switch is sensitive to magnetic fields.  The five turns ("5T" on the diagram) of wire around the switch act as an inductor, creating a magnetic field that will close the switch when the pitot heater is drawing current.  This will turn on the LED indicator without having to directly interrupt the feed to the heater or its control relay. 	
   Correct. See  http://tinyurl.com/htf4elj 

   Bob . . .

alec(at)alecmyers.com
Guest

Posted: Wed Feb 22, 2017 1:42 pm Post subject: Reedswitch

..and the meter in series inserts extra points of failure. 

The reed switch is such a smart idea because it's a parallel circuit, but one that's sensitive to the heat-providing current flowing.

On 22Feb2017, at 4:32 PM, Bernie Willis <arcticarrow(at)gmail.com> wrote:

That’s a cleaver idea.  I put an analog ammeter in the circuit for the same reason but not as sophisticated.

Bernie

 	  Quote: 	
		   On Feb 22, 2017, at 11:19 AM, Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com> wrote:

 At 09:52 PM 2/21/2017, you wrote:

> 

> 

> The reed switch is sensitive to magnetic fields.  The five turns ("5T" on the diagram) of wire around the switch act as an inductor, creating a magnetic field that will close the switch when the pitot heater is drawing current.  This will turn on the LED indicator without having to directly interrupt the feed to the heater or its control relay.

   Correct. See http://tinyurl.com/htf4elj

   Bob . . .

ceengland7(at)gmail.com
Guest

Posted: Wed Feb 22, 2017 2:22 pm Post subject: Reedswitch

Not heat; magnetism. The coil generates a magnetic field around the reed 

switch, closing it.

On 2/22/2017 3:39 PM, Alec Myers wrote:

 	  Quote: 	

 ...and the meter in series inserts extra points of failure.

 The reed switch is such a smart idea because it's a parallel circuit, but one that's sensitive to the heat-providing current flowing.

 On 22Feb2017, at 4:32 PM, Bernie Willis <arcticarrow(at)gmail.com> wrote:

 That’s a cleaver idea.  I put an analog ammeter in the circuit for the same reason but not as sophisticated.

 Bernie

> On Feb 22, 2017, at 11:19 AM, Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com> wrote:

>

> At 09:52 PM 2/21/2017, you wrote:

>> 

>>

>> The reed switch is sensitive to magnetic fields.  The five turns ("5T" on the diagram) of wire around the switch act as an inductor, creating a magnetic field that will close the switch when the pitot heater is drawing current.  This will turn on the LED indicator without having to directly interrupt the feed to the heater or its control relay.

>    Correct. See http://tinyurl.com/htf4elj

>

>    Bob . . .

>

alec(at)alecmyers.com
Guest

Posted: Wed Feb 22, 2017 3:10 pm Post subject: Reedswitch

It's a pitot heat circuit, right? We're sensing the current that generates the heat in the pitot head. I-squared R and all that.



 	  Quote: 	
		   On Feb 22, 2017, at 5:19 PM, Charlie England <ceengland7(at)gmail.com> wrote:

 

 

 

 Not heat; magnetism. The coil generates a magnetic field around the reed switch, closing it.

 

> On 2/22/2017 3:39 PM, Alec Myers wrote:

> 

> 

> ...and the meter in series inserts extra points of failure.

> The reed switch is such a smart idea because it's a parallel circuit, but one that's sensitive to the heat-providing current flowing.

> On 22Feb2017, at 4:32 PM, Bernie Willis <arcticarrow(at)gmail.com> wrote:

> 

> That’s a cleaver idea.  I put an analog ammeter in the circuit for the same reason but not as sophisticated.

> 

> Bernie

>> On Feb 22, 2017, at 11:19 AM, Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com> wrote:

>> 

>> At 09:52 PM 2/21/2017, you wrote:

>>> 

>>> 

>>> The reed switch is sensitive to magnetic fields.  The five turns ("5T" on the diagram) of wire around the switch act as an inductor, creating a magnetic field that will close the switch when the pitot heater is drawing current.  This will turn on the LED indicator without having to directly interrupt the feed to the heater or its control relay.

>>   Correct. See http://tinyurl.com/htf4elj

>> 

>>   Bob . . .

>>

ceengland7(at)gmail.com
Guest

Posted: Wed Feb 22, 2017 3:37 pm Post subject: Reedswitch

Sorry; the phrasing tricked me. I mis-read it as saying the reed switch 

was sensitive to the heat.



On 2/22/2017 5:05 PM, Alec Myers wrote:

 	  Quote: 	
		   



 It's a pitot heat circuit, right? We're sensing the current that generates the heat in the pitot head. I-squared R and all that.



> On Feb 22, 2017, at 5:19 PM, Charlie England <ceengland7(at)gmail.com> wrote:

>

> 

>

> Not heat; magnetism. The coil generates a magnetic field around the reed switch, closing it.

>

>> On 2/22/2017 3:39 PM, Alec Myers wrote:

>> 

>>

>> ...and the meter in series inserts extra points of failure.

>> The reed switch is such a smart idea because it's a parallel circuit, but one that's sensitive to the heat-providing current flowing.

>> On 22Feb2017, at 4:32 PM, Bernie Willis <arcticarrow(at)gmail.com> wrote:

>>

>> That’s a cleaver idea.  I put an analog ammeter in the circuit for the same reason but not as sophisticated.

>>

>> Bernie

>>> On Feb 22, 2017, at 11:19 AM, Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com> wrote:

>>>

>>> At 09:52 PM 2/21/2017, you wrote:

>>>> 

>>>>

>>>> The reed switch is sensitive to magnetic fields.  The five turns ("5T" on the diagram) of wire around the switch act as an inductor, creating a magnetic field that will close the switch when the pitot heater is drawing current.  This will turn on the LED indicator without having to directly interrupt the feed to the heater or its control relay.

>>>    Correct. See http://tinyurl.com/htf4elj

>>>

>>>    Bob . . .

>>>

Airdog77

Joined: 24 Nov 2013
Posts: 80
Location: Northern Virginia

Posted: Fri Feb 24, 2017 9:32 am Post subject: Re: Reedswitch

Bob, et al,



I'm a little confused on the implementation of a reed switch in a scenario as you have shown in the diagram on page 3 of your document: "Failure Warning w/ On Annunciation".  



I guess I don't understand why when using an LED to annunciate that is sourced with the SAME power as to the load being monitored.  Why not just tie into the relay (say out of the FastOn connector) with a separate wire with a 470 ohm resistor to the LED, then to ground.



IF using the SAME power as the end component being monitored (here, pitot heat), isn't an added wire as I described above really the end result that the reed switch provides when it's activated/closed? 



I could understand using the reed switch in a manner as a "poor man's relay" if the power source for the LED was completely separate from power source of the monitored load (again, here a pitot tube).  But in using the same power as the pitot heat, in this case, it seems like a bit of added complexity for no real gain?



I hope my question makes sense.  Not trying to be snarky, just trying to learn so I can implement the simplest, cleanest system possible ... and I have this exact issue for driving a few annunciator LEDs.



Thanks!

Wade

_________________
Airdog
Wade Parton
Building Long-EZ N916WP
www.longezpush.com

ceengland7(at)gmail.com
Guest

Posted: Fri Feb 24, 2017 9:52 am Post subject: Reedswitch

On Fri, Feb 24, 2017 at 11:32 AM, Airdog77 <Airdog77(at)gmail.com (Airdog77(at)gmail.com)> wrote:

 	  Quote: 	
		  --> AeroElectric-List message posted by: "Airdog77" <Airdog77(at)gmail.com (Airdog77(at)gmail.com)>

 

 Bob, et al,

 

 I'm a little confused on the implementation of a reed switch in a scenario as you have shown in the diagram on page 3 of your document: "Failure Warning w/ On Annunciation".

 

 I guess I don't understand why when using an LED to annunciate that is sourced with the SAME power as to the load being monitored.  Why not just tie into the relay (say out of the FastOn connector) with a separate wire with a 470 ohm resistor to the LED, then to ground.

 

 IF using the SAME power as the end component being monitored (here, pitot heat), isn't an added wire as I described above really the end result that the reed switch provides when it's activated/closed?

 

 I could understand using the reed switch in a manner as a "poor man's relay" if the power source for the LED was completely separate from power source of the monitored load (again, here a pitot tube).  But in using the same power as the pitot heat, in this case, it seems like a bit of added complexity for no real gain?

 

 I hope my question makes sense.  Not trying to be snarky, just trying to learn so I can implement the simplest, cleanest system possible ... and I have this exact issue for driving a few annunciator LEDs.

 

 Thanks!

 Wade

 

 --------

 Airdog

 Wade Parton

 Building Long-EZ 916WP

 www.longezpush.com



	
If the LED is wired directly to the power wire, and the wire breaks anywhere after your attach point for the LED, the LED is still lit but you have no pitot heat and no awareness. If the pitot heater itself fails, your LED is still lit, but you have no pitot heat & no awareness.



Using the coil & reed switch senses *current flow* through the heating element. If the circuit opens for any reason, the LED goes out, telling you you have no pitot heat.

Bob McC

Joined: 09 Jan 2006
Posts: 258
Location: Toronto, ON

Posted: Fri Feb 24, 2017 10:12 am Post subject: Reedswitch

Wade;   

The LED connected to the load as you describe only confirms that voltage is available at the load, not that the load is actually working. The read switch scenario confirms that current is being drawn by the load and therefore the pitot heater is actually heating and is not burned out.   

Bob McC   [quote]    

--------

_________________
Bob McC
Falco #908
(just starting)

user9253

Joined: 28 Mar 2008
Posts: 1927
Location: Riley TWP Michigan

Posted: Fri Feb 24, 2017 10:31 am Post subject: Re: Reedswitch

Double pole reed switches (Form C) are available with normally closed contacts.  The circuit could be wired so that a red LED illuminates only when the pitot heating element burns open.

_________________
Joe Gores

Airdog77

Joined: 24 Nov 2013
Posts: 80
Location: Northern Virginia

Posted: Fri Feb 24, 2017 10:41 am Post subject: Re: Reedswitch

Ahh, ok!  I was looking at it more from the binary on/off of the pitot tube.  But now I see the reed switch allows for a more qualitative monitoring of the pitot heat element's health in case it goes inop, wiring issue, etc.



Thanks all.  Love this forum!



Cheers,

Wade

_________________
Airdog
Wade Parton
Building Long-EZ N916WP
www.longezpush.com

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