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Thermocouple Wire Connections

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cluros(at)gmail.com
Guest

Posted: Thu Sep 13, 2018 6:48 am Post subject: Thermocouple Wire Connections

I am wiring some of these CHT probes to a Dynon Skyview

[img]cid:ii_jm0opve90_165d3639cd62b9f2[/img]

I'm hoping to connect them with these

https://buy-ei.com/portfolio/olc-1/



as recommended by Dynon but as you can see the probes come with bullet connectors. I don't have any female connectors for the bullets. Will it mess up the readings to cut the bullet connectors off, strip the wire, and connect them to the Dynon harness using the OLC-1s?

Thank you,

Sebastien

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BARRY CHECK 6

Joined: 15 Mar 2011
Posts: 738

Posted: Thu Sep 13, 2018 7:05 am Post subject: Thermocouple Wire Connections

Sebastien:

Not at all!Â  You just have to figure out the polarity.Â  Voltage output should be something like 23 microvolts per Deg F.

BUT!Â  Why do you want to use an Under The Spark Plug sensor?Â  In general:

1 - They read High.

2 - They are very slow in reacting.

3 - They break easy.

Your choice of wire connector is a good one.Â  I have done dozens & dozens of connections using that connector.Â  WAY easier to use them than the nut & bolt system from JPI.

Barry

On Thu, Sep 13, 2018 at 10:54 AM Sebastien <cluros(at)gmail.com (cluros(at)gmail.com)> wrote:



 	  Quote: 	
		  I am wiring some of these CHT probes to a Dynon Skyview

[img]cid:ii_jm0opve90_165d3639cd62b9f2[/img]

I'm hoping to connect them with these

https://buy-ei.com/portfolio/olc-1/



as recommended by Dynon but as you can see the probes come with bullet connectors. I don't have any female connectors for the bullets. Will it mess up the readings to cut the bullet connectors off, strip the wire, and connect them to the Dynon harness using the OLC-1s?

Thank you,

Sebastien

712-5WK.jpg

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36.71 KB

Viewed:

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nuckolls.bob(at)aeroelect
Guest

Posted: Thu Sep 13, 2018 7:16 am Post subject: Thermocouple Wire Connections

At 09:46 AM 9/13/2018, you wrote:

  	  Quote: 	
		  I am wiring some of these CHT probes to a Dynon Skyview



 [img]cid:.0[/img]

 I'm hoping to connect them with these



  https://buy-ei.com/portfolio/olc-1/



 as recommended by Dynon but as you can see the probes come with bullet connectors. I don't have any female connectors for the bullets. Will it mess up the readings to cut the bullet connectors off, strip the wire, and connect them to the Dynon harness using the OLC-1s? 	


   Looks good.  The cool thing about modern thermocouple

   sensor/indicator systems is the very low currents

   flowing in the thermocouple 'loop'. Back when

   thermocouples were used to POWER an instrument

   on the panel, the voltages were small but the

   currents significant . . . loop resistance had

   to be kept LOW and FIXED. Thermocouple wiring

   was rather fat. Long runs to measure CHT, EGT

   or oil TEMP on the outboard engines of something

   like the B29 might have been 18 or even 16AWG.



   This was because thermocouples like Type K . . .



 [img]cid:.1[/img]



   Generated only 7.7 MILLIVOLTS off reference 

   at 190 degrees-C.  Your error budget for voltage

   drop in wiring was exceedingly small!



   Nowadays, the panel mounted instruments are capable

   of resolving the 400 or so microvolt difference

   between 180 and 190C with a very high input impedance

   to the instrument. No need to maintain

   very low resistance pathways in the thermocouple

   loops You only need to manage parasitic

   couples.



   The OLC-1 brings like-metals in the T/C loop direcly

   in contact with each other . . . no parasitic couples.

   So while the OLC-1 splices would be frowned upon

   to join wires in a power feeder with significant

   current, potential for upsetting the accuracy

   in a modern thermocouple instrumentation loop is nil.



 

   Bob . . .

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glastar(at)gmx.net
Guest

Posted: Thu Sep 13, 2018 12:13 pm Post subject: Thermocouple Wire Connections

Barry, this is probably a Rotax engine, as far as I know they have only 

this kind of CHT probes, no boss mounted like on a Lycoming.



Cheers Werner



On 13.09.2018 16:59, FLYaDIVE wrote:

 	  Quote: 	
		   Sebastien:

 


	


 	  Quote: 	
		   BUT!Â  Why do you want to use an Under The Spark Plug sensor?Â  In general:

 1 - They read High.

 2 - They are very slow in reacting.

 3 - They break easy.

argoldman(at)aol.com
Guest

Posted: Thu Sep 13, 2018 2:13 pm Post subject: Thermocouple Wire Connections

Sebastien,



Those connectors should work however you may need to cut off the existing connectors on the wires to get a good connection

Rich



Sent from my iPhone



On Sep 13, 2018, at 9:59 AM, FLYaDIVE <flyadive(at)gmail.com (flyadive(at)gmail.com)> wrote:

 	  Quote: 	
		  Sebastien:

Not at all!  You just have to figure out the polarity.  Voltage output should be something like 23 microvolts per Deg F.

BUT!  Why do you want to use an Under The Spark Plug sensor?  In general:

1 - They read High.

2 - They are very slow in reacting.

3 - They break easy.

Your choice of wire connector is a good one.  I have done dozens & dozens of connections using that connector.  WAY easier to use them than the nut & bolt system from JPI.

Barry

On Thu, Sep 13, 2018 at 10:54 AM Sebastien <cluros(at)gmail.com (cluros(at)gmail.com)> wrote:



 	  Quote: 	
		  I am wiring some of these CHT probes to a Dynon Skyview

[img]cid:ii_jm0opve90_165d3639cd62b9f2[/img]

I'm hoping to connect them with these

https://buy-ei.com/portfolio/olc-1/



as recommended by Dynon but as you can see the probes come with bullet connectors. I don't have any female connectors for the bullets. Will it mess up the readings to cut the bullet connectors off, strip the wire, and connect them to the Dynon harness using the OLC-1s?

Thank you,

Sebastien

712-5WK.jpg

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rlborger(at)mac.com
Guest

Posted: Thu Sep 13, 2018 4:39 pm Post subject: Thermocouple Wire Connections

Werner,

My Rotax 914 has Rotax provided boss mounted thermal sensors on cylinders 1 and 4.  My GRT EIS 4000 can read their input quite well.  I put small ring thermal sensors provided by GRT onto the cylinder head of cylinders 2 and 3 by screwing them onto bosses provided.  They seem to read well enough as all 4 are very close in temperature readout.

Blue skies & tailwinds,Bob BorgerEuropa XS Tri, Rotax 914, Airmaster C/S Prop (130 hrs).Little Toot Sport Biplane, Lycoming Thunderbolt AEIO-320 EXP, Hercules Prop.3705 Lynchburg Dr.Corinth, TX  76208-5331Cel: 817-992-1117rlborger(at)mac.com (rlborger(at)mac.com)



On Sep 13, 2018, at 3:13 PM, Werner Schneider <glastar(at)gmx.net (glastar(at)gmx.net)> wrote:

--> AeroElectric-List message posted by: Werner Schneider <glastar(at)gmx.net (glastar(at)gmx.net)>Barry, this is probably a Rotax engine, as far as I know they have only this kind of CHT probes, no boss mounted like on a Lycoming.Cheers WernerOn 13.09.2018 16:59, FLYaDIVE wrote: 	  Quote: 	
		  Sebastien: 	
 	  Quote: 	
		  BUT!  Why do you want to use an Under The Spark Plug sensor?  In general:1 - They read High.2 - They are very slow in reacting.3 - They break easy.

BARRY CHECK 6

Joined: 15 Mar 2011
Posts: 738

Posted: Thu Sep 13, 2018 4:44 pm Post subject: Thermocouple Wire Connections

Werner:

Well, that explains it!

Question:Â  Aren't Rotax engines water cooled?Â  <--Â  The 4 cycle ones?

So, if they are water cooled would you use just ONE CHT Probe?

I do not work on Rotax so, I'm theorizing.

Thanks Werner,

Barry

On Thu, Sep 13, 2018 at 4:18 PM Werner Schneider <glastar(at)gmx.net (glastar(at)gmx.net)> wrote:

 	  Quote: 	
		  --> AeroElectric-List message posted by: Werner Schneider <glastar(at)gmx.net (glastar(at)gmx.net)>

 Barry, this is probably a Rotax engine, as far as I know they have only 

 this kind of CHT probes, no boss mounted like on a Lycoming.

 Cheers Werner

 On 13.09.2018 16:59, FLYaDIVE wrote:

 > Sebastien:

 > 

 > BUT!Â  Why do you want to use an Under The Spark Plug sensor?Â  In general:

 > 1 - They read High.

 > 2 - They are very slow in reacting.

 > 3 - They break easy.

 > 

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glastar(at)gmx.net
Guest

Posted: Fri Sep 14, 2018 12:51 am Post subject: Thermocouple Wire Connections

Thanks Bob for setting it right it's a while since I've worked on a 

Rotax  Do you know if the 912 has that as well meanwhile?



Cheers Werner



On 14.09.2018 02:37, Robert Borger wrote:

 	  Quote: 	
		   Werner,



 My Rotax 914 has Rotax provided boss mounted thermal sensors on 

 cylinders 1 and 4.  My GRT EIS 4000 can read their input quite well. 

  I put small ring thermal sensors provided by GRT onto the cylinder 

 head of cylinders 2 and 3 by screwing them onto bosses provided.  They 

 seem to read well enough as all 4 are very close in temperature readout.



 Blue skies & tailwinds,

 Bob Borger

BARRY CHECK 6

Joined: 15 Mar 2011
Posts: 738

Posted: Fri Sep 14, 2018 4:33 am Post subject: Thermocouple Wire Connections

Bob Borger & Werner,



Iâ€™m theorizing once again.Â  Since ROTAX has only two bosses for CHT sensors and they are diagonally opposit each other and the engine is water cooled the sensors must be averaging or at least â€˜mellowingâ€™ the readings.Â  It is more like a car which has only one temperature gauge. Â 

Question: Has anyone used a CHT reading to diagnose and pin point a particular cylinder problem?Â  Of course since there are only two cylinders with probes the problem would have to be on those cylinders.Â  Unless... There is such an increase in temperature that, it defines a problem.

BarryÂ 

======= Â 



On Friday, September 14, 2018, Werner Schneider <glastar(at)gmx.net (glastar(at)gmx.net)> wrote:

 	  Quote: 	
		  --> AeroElectric-List message posted by: Werner Schneider <glastar(at)gmx.net (glastar(at)gmx.net)>

 

 Thanks Bob for setting it right it's a while since I've worked on a Rotax  Do you know if the 912 has that as well meanwhile?

 

 Cheers Werner

 

 On 14.09.2018 02:37, Robert Borger wrote:

  	  Quote: 	
		   Werner,

 

 My Rotax 914 has Rotax provided boss mounted thermal sensors on cylinders 1 and 4.Â  My GRT EIS 4000 can read their input quite well.Â  I put small ring thermal sensors provided by GRT onto the cylinder head of cylinders 2 and 3 by screwing them onto bosses provided.Â  They seem to read well enough as all 4 are very close in temperature readout.

 

 Blue skies & tailwinds,

 Bob Borger

 	
 

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 Electric-List" target="_blank">http://www.matronics.com/Navigator?AeroElectric-List

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  FORUMS -

 _blank">http://forums.matronics.com

 ====================================

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 ====================================

 b Site -

 Â  Â  Â  Â  Â  -Matt Dralle, List Admin.

 target="_blank">http://www.matronics.com/contribution

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-- 

Barry

"Chop'd Liver"

If you wash your hands before you go to the bathroom you may have the makings of a Crew Chief.

rlborger(at)mac.com
Guest

Posted: Fri Sep 14, 2018 5:06 am Post subject: Thermocouple Wire Connections

Barry,



The Rotax 9xx series of engines have liquid cooled heads and air cooled cylinders.  The CHT sensors are placed on what should be the extremes of CHT.  #1 should be the coolest CHT and #4 should be the warmest CHT.  #2 & #3 should be somewhere in between.  Rotax also has a separate coolant temperature sensor on the output of the manifold where the 4 returns from the cylinder head combine.  



I donâ€™t think that CHT is used as a diagnostic in trouble shooting.  It is a warning of serious problems in the cylinder like detonation or preignition.  If one sees a rapidly increasing, out of limit, CHT, itâ€™s time to reduce the throttle and find a place to land.



Blue skies & tailwinds,

Bob Borger

Europa XS Tri, Rotax 914, Airmaster C/S Prop (130 hrs).

Little Toot Sport Biplane, Lycoming Thunderbolt AEIO-320 EXP, Hercules Prop.

3705 Lynchburg Dr.

Corinth, TX  76208-5331

Cel: 817-992-1117

rlborger(at)mac.com



On Sep 14, 2018, at 7:32 AM, FLYaDIVE <flyadive(at)gmail.com> wrote:



Bob Borger & Werner,



Iâ€™m theorizing once again.  Since ROTAX has only two bosses for CHT sensors and they are diagonally opposit each other and the engine is water cooled the sensors must be averaging or at least â€˜mellowingâ€™ the readings.  It is more like a car which has only one temperature gauge.  



Question: Has anyone used a CHT reading to diagnose and pin point a particular cylinder problem?  Of course since there are only two cylinders with probes the problem would have to be on those cylinders.  Unless... There is such an increase in temperature that, it defines a problem.



Barry

hamish.mead(at)gmail.com
Guest

Posted: Fri Sep 14, 2018 7:16 am Post subject: Thermocouple Wire Connections

Hi group,



My first post here after lurking for sometime, thank you 

Sebastien - perfect timing on this topic as I need to make up some new CHT probes to fit a Jabiru 2200 engine. You said:

 	  Quote: 	
		   I am wiring some of these CHT probes to a Dynon Skyview

Could you post a product link to the CHT probes/terminals please? (I only get the list daily digest and guess you posted an image - I'll change my subscription type in a moment).
	




Also; I read Bob's article on DIY CHT probes, but still have a few questions - hope the group don't mind overloading a thread:

So far I ordered some AMP / TE 328975 12 mm ring terminalsÂ PIDG R 22-16COMM 22-18MIL 1/2 (http://www.te.com/usa-en/product-328975.html) for the job - with a view to removing the Plastic Insulation prior to installing - but:

- wonder if the above terminals may be too thin compared to the following thicker, plain-copper ring terminals: (https://www.parts4aircraft.com/cht-probes-ring-type-c2x9382903) - leading to premature failure or exhaust gas blow-by?

- wonder if the tin plate on PIDG terminals is not ideal, due to max working temp of tinplate being 150ÂºC typically. Will it burn/evaporate off and all be ok, or should I anneal the terminals to cherry red prior fitting, much as a spark plug copper gasket would be?

Regarding CHT lead insulation: I initially bought Type K glassfibre insulated extension cable with stainless steel over-braiding (https://uk.rs-online.com/web/p/thermocouple-extension-wire/2194595/) as it was cheaper than the PTFE or PFA insulated variety, but found the glass fibres to be strongly bonded to one another and therefore very fiddly to strip.

- As such, any recommendations for/against using PTFE or PFA insulation types for making CHT probes in future would be appreciated, e.g. perhaps: (https://uk.rs-online.com/web/p/thermocouple-extension-wire/6118012/).

Many thanks,

Hamish

Ledbury, UK

Â Â

cluros(at)gmail.com
Guest

Posted: Fri Sep 14, 2018 7:45 am Post subject: Thermocouple Wire Connections

westach.com > products > accessories > under spark plug ring type thermocouples



Aircraft Spruce carries many Westach products.

On Fri, Sep 14, 2018 at 8:15 AM, Hamish Mead <hamish.mead(at)gmail.com (hamish.mead(at)gmail.com)> wrote:

 	  Quote: 	
		  Hi group,



My first post here after lurking for sometime, thank you 

Sebastien - perfect timing on this topic as I need to make up some new CHT probes to fit a Jabiru 2200 engine. You said:

 	  Quote: 	
		   I am wiring some of these CHT probes to a Dynon Skyview

Could you post a product link to the CHT probes/terminals please? (I only get the list daily digest and guess you posted an image - I'll change my subscription type in a moment).
	




Also; I read Bob's article on DIY CHT probes, but still have a few questions - hope the group don't mind overloading a thread:

So far I ordered some AMP / TE 328975 12 mm ring terminalsÂ PIDG R 22-16COMM 22-18MIL 1/2 (http://www.te.com/usa-en/product-328975.html) for the job - with a view to removing the Plastic Insulation prior to installing - but:

- wonder if the above terminals may be too thin compared to the following thicker, plain-copper ring terminals: (https://www.parts4aircraft.com/cht-probes-ring-type-c2x9382903) - leading to premature failure or exhaust gas blow-by?

- wonder if the tin plate on PIDG terminals is not ideal, due to max working temp of tinplate being 150ÂºC typically. Will it burn/evaporate off and all be ok, or should I anneal the terminals to cherry red prior fitting, much as a spark plug copper gasket would be?

Regarding CHT lead insulation: I initially bought Type K glassfibre insulated extension cable with stainless steel over-braiding (https://uk.rs-online.com/web/p/thermocouple-extension-wire/2194595/) as it was cheaper than the PTFE or PFA insulated variety, but found the glass fibres to be strongly bonded to one another and therefore very fiddly to strip.

- As such, any recommendations for/against using PTFE or PFA insulation types for making CHT probes in future would be appreciated, e.g. perhaps: (https://uk.rs-online.com/web/p/thermocouple-extension-wire/6118012/).

Many thanks,

Hamish

Ledbury, UK

Â Â

rlborger(at)mac.com
Guest

Posted: Fri Sep 14, 2018 8:01 am Post subject: Thermocouple Wire Connections

Werner,



Yes, the 912 has the same arrangement of CHT sensors.



Blue skies & tailwinds,

Bob Borger

Europa XS Tri, Rotax 914, Airmaster C/S Prop (130 hrs).

Little Toot Sport Biplane, Lycoming Thunderbolt AEIO-320 EXP, Hercules Prop.

3705 Lynchburg Dr.

Corinth, TX  76208-5331

Cel: 817-992-1117

rlborger(at)mac.com



On Sep 14, 2018, at 3:50 AM, Werner Schneider <glastar(at)gmx.net> wrote:






Thanks Bob for setting it right it's a while since I've worked on a Rotax  Do you know if the 912 has that as well meanwhile?



Cheers Werner



On 14.09.2018 02:37, Robert Borger wrote:

 	  Quote: 	
		   Werner,

 

 My Rotax 914 has Rotax provided boss mounted thermal sensors on cylinders 1 and 4.  My GRT EIS 4000 can read their input quite well.  I put small ring thermal sensors provided by GRT onto the cylinder head of cylinders 2 and 3 by screwing them onto bosses provided.  They seem to read well enough as all 4 are very close in temperature readout.

 

 Blue skies & tailwinds,

 Bob Borger

argoldman(at)aol.com
Guest

Posted: Fri Sep 14, 2018 7:21 pm Post subject: Thermocouple Wire Connections

Speaking of thermocouplesâ€”-



Can one thermocouple be connected to two readout devices???

Thanks

Rich



Sent from my iPhone



On Sep 13, 2018, at 9:59 AM, FLYaDIVE <flyadive(at)gmail.com (flyadive(at)gmail.com)> wrote:

 	  Quote: 	
		  Sebastien:

Not at all!  You just have to figure out the polarity.  Voltage output should be something like 23 microvolts per Deg F.

BUT!  Why do you want to use an Under The Spark Plug sensor?  In general:

1 - They read High.

2 - They are very slow in reacting.

3 - They break easy.

Your choice of wire connector is a good one.  I have done dozens & dozens of connections using that connector.  WAY easier to use them than the nut & bolt system from JPI.

Barry

On Thu, Sep 13, 2018 at 10:54 AM Sebastien <cluros(at)gmail.com (cluros(at)gmail.com)> wrote:



 	  Quote: 	
		  I am wiring some of these CHT probes to a Dynon Skyview

<712-5WK.jpg>

I'm hoping to connect them with these

https://buy-ei.com/portfolio/olc-1/



as recommended by Dynon but as you can see the probes come with bullet connectors. I don't have any female connectors for the bullets. Will it mess up the readings to cut the bullet connectors off, strip the wire, and connect them to the Dynon harness using the OLC-1s?

Thank you,

Sebastien

BARRY CHECK 6

Joined: 15 Mar 2011
Posts: 738

Posted: Thu Sep 20, 2018 4:04 pm Post subject: Thermocouple Wire Connections

B. Borger:

Thank you for the explanation.Â Â 

And sorry it took so long to respond.Â  Your email was sent to the Spam Folder.

Barry

On Fri, Sep 14, 2018 at 9:11 AM Robert Borger <rlborger(at)mac.com (rlborger(at)mac.com)> wrote:



 	  Quote: 	
		  --> AeroElectric-List message posted by: Robert Borger <rlborger(at)mac.com>

 

 Barry,

 

 The Rotax 9xx series of engines have liquid cooled heads and air cooled cylinders.Â  The CHT sensors are placed on what should be the extremes of CHT.Â  #1 should be the coolest CHT and #4 should be the warmest CHT.Â  #2 & #3 should be somewhere in between.Â  Rotax also has a separate coolant temperature sensor on the output of the manifold where the 4 returns from the cylinder head combine.Â  

 

 I donâ€™t think that CHT is used as a diagnostic in trouble shooting.Â  It is a warning of serious problems in the cylinder like detonation or preignition.Â  If one sees a rapidly increasing, out of limit, CHT, itâ€™s time to reduce the throttle and find a place to land.

 

 Blue skies & tailwinds,

 Bob Borger

 Europa XS Tri, Rotax 914, Airmaster C/S Prop (130 hrs).

 Little Toot Sport Biplane, Lycoming Thunderbolt AEIO-320 EXP, Hercules Prop.

 3705 Lynchburg Dr.

 Corinth, TXÂ  76208-5331

 Cel: 817-992-1117

 rlborger(at)mac.com

 

 On Sep 14, 2018, at 7:32 AM, FLYaDIVE <flyadive(at)gmail.com> wrote:

 

 Bob Borger & Werner,

 

 Iâ€™m theorizing once again.Â  Since ROTAX has only two bosses for CHT sensors and they are diagonally opposit each other and the engine is water cooled the sensors must be averaging or at least â€˜mellowingâ€™ the readings.Â  It is more like a car which has only one temperature gauge.Â  

 

 Question: Has anyone used a CHT reading to diagnose and pin point a particular cylinder problem?Â  Of course since there are only two cylinders with probes the problem would have to be on those cylinders.Â  Unless... There is such an increase in temperature that, it defines a problem.

 

 Barry 

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