Matronics Email Lists :: View topic

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

Relay sticking

Matronics Email Lists Forum Index -> AeroElectric-List

View previous topic :: View next topic

Author Message

cluros(at)gmail.com
Guest

Posted: Mon Dec 24, 2018 5:15 pm Post subject: Relay sticking

We had a strange event last week with our O-200 powered CH750. After running the battery down during a fuel gauge calibration that lasted over an hour, one of our pilots tried to start the engine to taxi back but with the already depleted battery and a less than perfect start procedure they gave up after a couple weak start attempts. I walked over to the aircraft to brief them on a prop start and when I asked for the master on the starter ran. Shut the master off, cycled the start button rapidly a dozen times, master on again and the starter ran again. I could hear the starter relay clicking loudly each time power was applied so it does not seem like there was a physical failure of the relay but more some electrical short activating the relay each time power was applied.



The build team inspected the relay and found a loose connection. Tightening it took the problem from continuous to intermittent; in their words "it's fixed but it did it again once".

We have removed the relay for replacement, I still think the switch is suspect but they've decided the problem is the relay. Does the aeroelectric list think there would be value in cutting open the relay and examining it? Any suggestions on how best to do so?

Thank you,

Sebastien

Kellym

Joined: 10 Jan 2006
Posts: 1705
Location: Sun Lakes AZ

Posted: Mon Dec 24, 2018 6:12 pm Post subject: Relay sticking

I don't think you have a problem. I think that if the engine didn't 

actually start, the starter might not reach enough speed to disengage.

Also, extended cranking at low voltage probably heated the solenoid a 

lot, causing sticking in it. After the battery is fully recharged, give 

it another try, without cranking more than 10-15 seconds on any try. It 

is likely to start, and the starter will disengage normally. You can 

test the relay on the bench, without a starter connected, just battery 

cable on input side and switchable 12V on ignition terminal, just 

activating long enough to see your multi-meter show voltage on the 

output terminal.



On 12/24/2018 6:14 PM, Sebastien wrote:

 	  Quote: 	
		   We had a strange event last week with our O-200 powered CH750. After 

 running the battery down during a fuel gauge calibration that lasted 

 over an hour, one of our pilots tried to start the engine to taxi back 

 but with the already depleted battery and a less than perfect start 

 procedure they gave up after a couple weak start attempts. I walked over 

 to the aircraft to brief them on a prop start and when I asked for the 

 master on the starter ran. Shut the master off, cycled the start button 

 rapidly a dozen times, master on again and the starter ran again. I 

 could hear the starter relay clicking loudly each time power was applied 

 so it does not seem like there was a physical failure of the relay but 

 more some electrical short activating the relay each time power was applied.

 

 The build team inspected the relay and found a loose connection. 

 Tightening it took the problem from continuous to intermittent; in their 

 words "it's fixed but it did it again once".

 

 We have removed the relay for replacement, I still think the switch is 

 suspect but they've decided the problem is the relay. Does the 

 aeroelectric list think there would be value in cutting open the relay 

 and examining it? Any suggestions on how best to do so?

 

 Thank you,

 

 Sebastien

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD

alec(at)alecmyers.com
Guest

Posted: Mon Dec 24, 2018 8:46 pm Post subject: Relay sticking

I say change the relay. (And have done, on two different aircraft, for identical symptoms.) If the relay sticks on a good engine start it will take the starter motor with it, unless you shut it down soon, and itâ€™s hard to spot unless you have a â€œstarter energizedâ€ lamp. In my case I was lucky, the massive current drain took the radio out before I took off, but I only worked out why when I heard the weird grinding noise of the engine driving the locked up starter when I took my headset off. 



That was an O235 engine, similar starter configuration to yours.



Do you have a â€œstarter energizedâ€ lamp?



On Dec 24, 2018, at 21:04, Kelly McMullen <kellym(at)aviating.com> wrote:






I don't think you have a problem. I think that if the engine didn't actually start, the starter might not reach enough speed to disengage.

Also, extended cranking at low voltage probably heated the solenoid a lot, causing sticking in it. After the battery is fully recharged, give it another try, without cranking more than 10-15 seconds on any try. It is likely to start, and the starter will disengage normally. You can test the relay on the bench, without a starter connected, just battery cable on input side and switchable 12V on ignition terminal, just activating long enough to see your multi-meter show voltage on the output terminal.



 	  Quote: 	
		   On 12/24/2018 6:14 PM, Sebastien wrote:

 We had a strange event last week with our O-200 powered CH750. After running the battery down during a fuel gauge calibration that lasted over an hour, one of our pilots tried to start the engine to taxi back but with the already depleted battery and a less than perfect start procedure they gave up after a couple weak start attempts. I walked over to the aircraft to brief them on a prop start and when I asked for the master on the starter ran. Shut the master off, cycled the start button rapidly a dozen times, master on again and the starter ran again. I could hear the starter relay clicking loudly each time power was applied so it does not seem like there was a physical failure of the relay but more some electrical short activating the relay each time power was applied.

 The build team inspected the relay and found a loose connection. Tightening it took the problem from continuous to intermittent; in their words "it's fixed but it did it again once".

 We have removed the relay for replacement, I still think the switch is suspect but they've decided the problem is the relay. Does the aeroelectric list think there would be value in cutting open the relay and examining it? Any suggestions on how best to do so?

 Thank you,

 Sebastien

cluros(at)gmail.com
Guest

Posted: Mon Dec 24, 2018 9:09 pm Post subject: Relay sticking

We do not have a starter energized light but we do have a Dynon Skyview so I'm thinking there must be a way of connecting it to a GP input to display a warning. Have not checked the Dynon install manual yet.

On Mon, Dec 24, 2018, 20:50 Alec Myers <alec(at)alecmyers.com (alec(at)alecmyers.com) wrote:

 	  Quote: 	
		  --> AeroElectric-List message posted by: Alec Myers <alec(at)alecmyers.com (alec(at)alecmyers.com)>

 I say change the relay. (And have done, on two different aircraft, for identical symptoms.) If the relay sticks on a good engine start it will take the starter motor with it, unless you shut it down soon, and itâ€™s hard to spot unless you have a â€œstarter energizedâ€ lamp. In my case I was lucky, the massive current drain took the radio out before I took off, but I only worked out why when I heard the weird grinding noise of the engine driving the locked up starter when I took my headset off. 

 That was an O235 engine, similar starter configuration to yours.

 Do you have a â€œstarter energizedâ€ lamp?

 On Dec 24, 2018, at 21:04, Kelly McMullen <kellym(at)aviating.com (kellym(at)aviating.com)> wrote:

 --> AeroElectric-List message posted by: Kelly McMullen <kellym(at)aviating.com (kellym(at)aviating.com)>

 I don't think you have a problem. I think that if the engine didn't actually start, the starter might not reach enough speed to disengage.

 Also, extended cranking at low voltage probably heated the solenoid a lot, causing sticking in it. After the battery is fully recharged, give it another try, without cranking more than 10-15 seconds on any try. It is likely to start, and the starter will disengage normally. You can test the relay on the bench, without a starter connected, just battery cable on input side and switchable 12V on ignition terminal, just activating long enough to see your multi-meter show voltage on the output terminal.

 > On 12/24/2018 6:14 PM, Sebastien wrote:

 > We had a strange event last week with our O-200 powered CH750. After running the battery down during a fuel gauge calibration that lasted over an hour, one of our pilots tried to start the engine to taxi back but with the already depleted battery and a less than perfect start procedure they gave up after a couple weak start attempts. I walked over to the aircraft to brief them on a prop start and when I asked for the master on the starter ran. Shut the master off, cycled the start button rapidly a dozen times, master on again and the starter ran again. I could hear the starter relay clicking loudly each time power was applied so it does not seem like there was a physical failure of the relay but more some electrical short activating the relay each time power was applied.

 > The build team inspected the relay and found a loose connection. Tightening it took the problem from continuous to intermittent; in their words "it's fixed but it did it again once".

 > We have removed the relay for replacement, I still think the switch is suspect but they've decided the problem is the relay. Does the aeroelectric list think there would be value in cutting open the relay and examining it? Any suggestions on how best to do so?

 > Thank you,

 > Sebastien

 ===========

 br> fts!)

 r> > e.com" rel="noreferrer noreferrer noreferrer" target="_blank">www.mypilotstore.com

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

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

 ===========

  -

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

 ===========

  FORUMS -

 eferrer noreferrer noreferrer" target="_blank">http://forums.matronics.com

 ===========

 WIKI -

 errer noreferrer noreferrer" target="_blank">http://wiki.matronics.com

 ===========

 b Site -

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

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

 ===========

Kellym

Joined: 10 Jan 2006
Posts: 1705
Location: Sun Lakes AZ

Posted: Tue Dec 25, 2018 7:46 am Post subject: Relay sticking

Be very careful with your generalizations. A Continental starter is very 

different than a Lycoming starter. There are no models I know of shared 

between those brands. So it is pretty unlikely that they are "similar 

configuration". Lycoming starters are on the front of the engine, 

Continentals on the rear of the engine, just for example. Some  may have 

a relay (solenoid) mounted on the starter, some do not. You may be right 

about replacing relay, given the generally low cost.

Yes, having a starter energized lamp is a good suggestion regardless.



On 12/24/2018 9:45 PM, Alec Myers wrote:

 	  Quote: 	
		   

 

 I say change the relay.  

 

 That was an O235 engine, similar starter configuration to yours.

 

 Do you have a â€œstarter energizedâ€ lamp?

_________________
Kelly McMullen
A&P/IA, EAA Tech Counselor # 5286
KCHD

alec(at)alecmyers.com
Guest

Posted: Tue Dec 25, 2018 9:36 am Post subject: Relay sticking

On Dec 25, 2018, at 10:45 AM, Kelly McMullen <kellym(at)aviating.com> wrote:






 	  Quote: 	
		  Be very careful with your generalizations. A Continental starter is very different than a Lycoming starter. There are no models I know of shared between those brands. So it is pretty unlikely that they are "similar configurationâ€.


	


For sure. I understood Sebastien had a Lycoming O-200, and the aircraft I was writing about has a lycoming O-235. If he has a Continental O-200 then theyâ€™re not similar. 



However the second engine wth which I had a sticky starter solenoid problem was a Continental IO-470, where the starter adapter is damaged within a few seconds of a locked up starter contactor, The starter adapter is impossible to reach without removing the engine from the aircraft. Lycoming - or Continental - I would take absolutely no chances with running either engine with the slightest suspicion of a sticky solenoid.

alec(at)alecmyers.com
Guest

Posted: Tue Dec 25, 2018 9:38 am Post subject: Relay sticking

Sorry - I should be less ambiguous. Weâ€™re talking about sticky starter *contactors* - regardless of whether the starter has a solenoid or some other engagement mechanism. A new contactor is about $100 for a PMA one. Princess Auto (I know Sebastien is in Canada) used to do an intermittent duty 12v contactor of identical dimensions for CDN$16.



On Dec 25, 2018, at 11:55 AM, Alec Myers <alec(at)alecmyers.com> wrote:



On Dec 25, 2018, at 10:45 AM, Kelly McMullen <kellym(at)aviating.com> wrote:






 	  Quote: 	
		   Be very careful with your generalizations. A Continental starter is very different than a Lycoming starter. There are no models I know of shared between those brands. So it is pretty unlikely that they are "similar configurationâ€.


	


For sure. I understood Sebastien had a Lycoming O-200, and the aircraft I was writing about has a lycoming O-235. If he has a Continental O-200 then theyâ€™re not similar. 



However the second engine wth which I had a sticky starter solenoid problem was a Continental IO-470, where the starter adapter is damaged within a few seconds of a locked up starter contactor, The starter adapter is impossible to reach without removing the engine from the aircraft. Lycoming - or Continental - I would take absolutely no chances with running either engine with the slightest suspicion of a sticky solenoid.

cluros(at)gmail.com
Guest

Posted: Tue Dec 25, 2018 9:58 am Post subject: Relay sticking

Sorry, I didn't know Lycoming made an O-200, this one is a Continental. In any case we think the problem is in the relay or switch, not the starter itself.



We are planning on replacing the relay with one of these:

https://aircraftspruce.ca/catalog/elpages/starterrelay.php



At $20Â it seems a good idea.

What I'm wondering about is how to best cut open the old one in order to see how the failure may have occurred?

On Tue, Dec 25, 2018, 09:43 Alec Myers <alec(at)alecmyers.com (alec(at)alecmyers.com) wrote:



 	  Quote: 	
		  --> AeroElectric-List message posted by: Alec Myers <alec(at)alecmyers.com (alec(at)alecmyers.com)>

 

 Sorry - I should be less ambiguous. Weâ€™re talking about sticky starter *contactors* - regardless of whether the starter has a solenoid or some other engagement mechanism. A new contactor is about $100 for a PMA one. Princess Auto (I know Sebastien is in Canada) used to do an intermittent duty 12v contactor of identical dimensions for CDN$16.

 

 

 

 On Dec 25, 2018, at 11:55 AM, Alec Myers <alec(at)alecmyers.com (alec(at)alecmyers.com)> wrote:

 

 

 

 On Dec 25, 2018, at 10:45 AM, Kelly McMullen <kellym(at)aviating.com (kellym(at)aviating.com)> wrote:

 

 --> AeroElectric-List message posted by: Kelly McMullen <kellym(at)aviating.com (kellym(at)aviating.com)>

 

 > Be very careful with your generalizations. A Continental starter is very different than a Lycoming starter. There are no models I know of shared between those brands. So it is pretty unlikely that they are "similar configurationâ€.

 

 For sure. I understood Sebastien had a Lycoming O-200, and the aircraft I was writing about has a lycoming O-235. If he has a Continental O-200 then theyâ€™re not similar. 

 

 However the second engine wth which I had a sticky starter solenoid problem was a Continental IO-470, where the starter adapter is damaged within a few seconds of a locked up starter contactor, The starter adapter is impossible to reach without removing the engine from the aircraft. Lycoming - or Continental - I would take absolutely no chances with running either engine with the slightest suspicion of a sticky solenoid.

 

 

 ===========

 br> fts!)

 r> > e.com" rel="noreferrer noreferrer noreferrer" target="_blank">www.mypilotstore.com

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

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

 ===========

  -

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

 ===========

  FORUMS -

 eferrer noreferrer noreferrer" target="_blank">http://forums.matronics.com

 ===========

 WIKI -

 errer noreferrer noreferrer" target="_blank">http://wiki.matronics.com

 ===========

 b Site -

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

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

 ===========

alec(at)alecmyers.com
Guest

Posted: Tue Dec 25, 2018 10:07 am Post subject: Relay sticking

 	  Quote: 	
		  Sorry, I didn't know Lycoming made an O-200,


	


After checking, I guess they donâ€™t! Sorry for the confusion.

BARRY CHECK 6

Joined: 15 Mar 2011
Posts: 738

Posted: Tue Dec 25, 2018 7:21 pm Post subject: Relay sticking

Sabastien:

There are three test you should do:

1 - Test the Relay

2 - Test the Start Switch

3 - Test the wiring for the Start Switch

Test the Relay - Test 1:

a> Remove the wires connected to the relay.

b> Using an Ohm Meter read across the Contacts



Without power applied to the relay you should read an open.Â Â 



c> Using an Ohm Meter read across the Coil



You should read some value of resistance.

The issue is:Â  IS there one contact or two?

If one, then the case is your other contact.

AND one contact COULD BE off the INPUT side which would be your B+

d> Using an Ohm Meter read across ONE Coil to Ground (CASE) and thenÂ Â 

e> Using an Ohm Meter read across ONE (the other ) Coil to Ground (CASE)



Start Switch Test 2:

a> Remove the wires to the Start Switch.

b> Using an Ohm Meter read across the Contacts

With the switch NOT pressed it should read open

c> Press the Switch.

With the switch pressed it should read closed (zero ohms).

If anything other than above replace the switch.

Test the wiring for the Start Switch Test 3:

a> Since you have the wires already disconnected from the Switch and the Relay you can do two checks

a1> Across the wires that came off the Start Switch.

They should read open.

a2> From ONE end of a wire from the switch to the other end of the wire where it connects to the Start Relay.Â 

You should read a close (zero ohms) for each wire.

IF you get anything other than the above - Replace the wires.

OK - Are you ready to POWER TEST the Starter Relay?

IF SO - DISCONNECT IT FROM THE STARTER MOTOR.

Well, it already should have been done if you followed instructions in Test 1.

Using a set of jumper leads.



Run a lead from the BatteryÂ + to the INPUT side of the Start Relay.

Run a second lead from the Battery - (Ground) to the Coil terminal of the relay.

It should snap CLOSED.

Well, it may not IF you have a relay that has two (2) Coil Terminals.Â  Some relays use an independentÂ + & - connections.Â Â Â 

IF you have a single coil terminal your INPUT Battery B+ will be readable on the OUTPUT relay terminal.Â  Now, here is a TRICK -Â 

Step 1:Â  Read the Voltage across the CLOSED relay terminals.Â  It should read ZERO!

If you have a voltage that means there is a RESISTANCE internally in the relay contacts.Â Â 

Throw the relay away!

Step 2: While CLOSED,Â  take a resistance reading Across the Input & Output.

You should read ZERO Ohms.Â  Why do I call this a TRICK?Â  Because you are reading a Resistance while there is a voltage on the same terminals.Â  YEAH!Â  It is possible to read resistance.Â  And, if you do...Â  Throw the relay away.Â  You want ZERO resistance.

Last test:Â  Does the relay have Diode across the Coil?Â Â 

1 - It should be installed with theÂ + side of the Diode on the Negative - side of the Coil.

2 - CheckÂ  the Diode for Forward to Reverse Bias Resistance.Â  There should be a Minimum of 10:1 Reverse to Forward.Â Â 

OR...Â  Just throw it away and replace it with a New Diode.

OR...Â  Of course you could just replace the relay and diode without testing it.Â  That way you know the circuit has a good relay - But,Â  you have no proof that the old relay is bad.Â  What about the wires and the Start Switch?

Side Note:Â  I always, well, almost always,Â  use the above procedure ONLY because sometimes the R&R of the relay is way more time consuming and/or requires two people.Â  AND, I hate being a Pull & Replace Mechanic.Â  You would never know if it was the relay or just a bad ground.

Barry

On Mon, Dec 24, 2018 at 8:19 PM Sebastien <cluros(at)gmail.com (cluros(at)gmail.com)> wrote:



 	  Quote: 	
		  We had a strange event last week with our O-200 powered CH750. After running the battery down during a fuel gauge calibration that lasted over an hour, one of our pilots tried to start the engine to taxi back but with the already depleted battery and a less than perfect start procedure they gave up after a couple weak start attempts. I walked over to the aircraft to brief them on a prop start and when I asked for the master on the starter ran. Shut the master off, cycled the start button rapidly a dozen times, master on again and the starter ran again. I could hear the starter relay clicking loudly each time power was applied so it does not seem like there was a physical failure of the relay but more some electrical short activating the relay each time power was applied.



The build team inspected the relay and found a loose connection. Tightening it took the problem from continuous to intermittent; in their words "it's fixed but it did it again once".

We have removed the relay for replacement, I still think the switch is suspect but they've decided the problem is the relay. Does the aeroelectric list think there would be value in cutting open the relay and examining it? Any suggestions on how best to do so?

Thank you,

Sebastien

nuckolls.bob(at)aeroelect
Guest

Posted: Thu Dec 27, 2018 9:11 am Post subject: Relay sticking

At 07:14 PM 12/24/2018, you wrote:

  	  Quote: 	
		  We had a strange event last week with our O-200 powered CH750. After running the battery down during a fuel gauge calibration that lasted over an hour, one of our pilots tried to start the engine to taxi back but with the already depleted battery and a less than perfect start procedure they gave up after a couple weak start attempts. I walked over to the aircraft to brief them on a prop start and when I asked for the master on the starter ran. 	


  The vast majority of starter contactor

  sticking events occur during an attempt

  to crank the engine with a weak battery.

  The fact that you got immediate starter

  action on closure of the master switch

  says your starter contactor was 'stuck'

  shut.



  	  Quote: 	
		   Shut the master off, cycled the start button rapidly a dozen times, master on again and the starter ran again. I could hear the starter relay clicking loudly each time power was applied so it does not seem like there was a physical failure of the relay but more some electrical short activating the relay each time power was applied. 	


  Contacts are welded . . .



 

  	  Quote: 	
		  The build team inspected the relay and found a loose connection. Tightening it took the problem from continuous to intermittent; in their words "it's fixed but it did it again once".



 We have removed the relay for replacement, I still think the switch is suspect but they've decided the problem is the relay. Does the aeroelectric list think there would be value in cutting open the relay and examining it? Any suggestions on how best to do so? 	


  Go to a car parts store and pick

  up a starter contactor that looks

  like the one in the aircraft spruce

  catalog . . . it will work just fine.

  See if the contactor is marked "diode

  suppressed" or has the word diode on it

  anywhere or on the packaging. 



 [img]cid:.0[/img]



 

   



 

   Bob . . .

20960049.jpg

Description:

Filesize:

156.73 KB

Viewed:

11530 Time(s)

nuckolls.bob(at)aeroelect
Guest

Posted: Thu Dec 27, 2018 9:12 am Post subject: Relay sticking

At 11:56 AM 12/25/2018, you wrote:

  	  Quote: 	
		  Sorry, I didn't know Lycoming made an O-200, this one is a Continental. In any case we think the problem is in the relay or switch, not the starter itself.



 We are planning on replacing the relay with one of these:



  https://aircraftspruce.ca/catalog/elpages/starterrelay.php



 At $20Â it seems a good idea. 	


   Any similar contactor from your local car-parts

   emporium will do nicely . . .



 

  	  Quote: 	
		  What I'm wondering about is how to best cut open the old one in order to see how the failure may have occurred? 	


   Send it to me and I'll conduct an

   'up town' failure analysis and report

   back.



 

 

   Bob . . .

BARRY CHECK 6

Joined: 15 Mar 2011
Posts: 738

Posted: Thu Dec 27, 2018 6:04 pm Post subject: Relay sticking

Bob,



Cutting open of a relay depends on the design of the relay.Â  If you are talking the standard hermetically sealed / rolled over edge type, you do NOT cut it open...Â  You simply grind off the rolled over edge.Â  This can be done very carefully so none of the metal filings enter the relay.Â  If done carefully you may even find water inside the relay.Â  That is what I found in mine! Â 

Next trick: Â If you replace the relay with the same kind (hermetically sealed) do the following:

Get a pint of epoxy paint.

Mask the terminals of the relay.

Using a heat gun heat the relay hot enough that you can not touch it.

Then totally submerge the relay in the epoxy paint.

As the relay cools it will suck in the epoxy paint into the rolled edge and seal out any paint.

NOW!Â  You have a hermetically sealed relay.

Not done yet...Â  Next trick: Â Make sure you mount the relay so the edge of the rolled edge is facing DOWN.Â  Now water and ice will not collect.





Barry



On Thursday, December 27, 2018, Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:

 	  Quote: 	
		    At 11:56 AM 12/25/2018, you wrote:

  	  Quote: 	
		  Sorry, I didn't know Lycoming made an O-200, this one is a Continental. In any case we think the problem is in the relay or switch, not the starter itself.



 We are planning on replacing the relay with one of these:



  https://aircraftspruce.ca/catalog/elpages/starterrelay.php



 At $20Ã‚ it seems a good idea. 	


 Â  Any similar contactor from your local car-parts

 Â  emporium will do nicely . . .



 

  	  Quote: 	
		  What I'm wondering about is how to best cut open the old one in order to see how the failure may have occurred? 	


 Â  Send it to me and I'll conduct an

 Â  'up town' failure analysis and report

 Â  back.



 

 

 Â  Bob . . .  

	


-- 

Barry

"Chop'd Liver"

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

nuckolls.bob(at)aeroelect
Guest

Posted: Thu Dec 27, 2018 7:02 pm Post subject: Relay sticking

At 08:02 PM 12/27/2018, you wrote:

  	  Quote: 	
		  Bob,



 Cutting open of a relay depends on the design of the relay.Â  If you are talking the standard hermetically sealed 	


   hermetically sealed implies

   absolute atmospheric isolation

   between interior and the 

   environment. Contactors with

   rolled on caps are not 'hermetic',

   only very secure.



 

  	  Quote: 	
		   / rolled over edge type, you do NOT cut it open...Â  You simply grind off the rolled over edge.Â  This can be done very carefully so none of the metal filings enter the relay.Â  If done carefully you may even find water inside the relay.Â  That is what I found in mine! Â 	


   Yep . . . been there a few dozen times.



  https://tinyurl.com/p2x7fbl



  https://tinyurl.com/kcc26jt



   Cessna attempted some DIY sealing techniques

   on the whisky barrel relays . . . right

   after the noise reducing, floating cowl

   was incorporated onto the SE aircraft.

   Virtually no help. You could not guarantee

   quality of seal. Liquid water sucked in

   during a cooling event had to exit as a vapor

   over successive atmospheric 'breathing'

   cycles . . . i.e. once inside it stayed

   inside. 



 

  	  Quote: 	
		  Not done yet...Â  Next trick: Â Make sure you mount the relay so the edge of the rolled edge is facing DOWN.Â  Now water and ice will not collect.

 	


   or cap facing down with a #40 drain

   hole added right in the center. Now

   trapped liquid had a place to get

   out.



 

 

   Bob . . .

nuckolls.bob(at)aeroelect
Guest

Posted: Wed Jan 02, 2019 6:17 am Post subject: Relay sticking

 	  Quote: 	
		    	  Quote: 	
		   	


  or cap facing down with a #40 drain

  hole added right in the center. Now

  trapped liquid had a place to get

  out.

  

 Barry - You must be associated with the Three Stooges...  Remember when they were sitting in a row boat and it sprung

 a leak...  If you have a hole at one end of the boat leaking water in, all you have to do is drill another hole at

 the other end to let the water out! Isn't that correct? That is EXACTLY what you are suggesting.  Also, you did

 not address the issue of having the rolled edge facing Up where water and ice can accumulate. 



 Bob, if you continue to attack me with your warped logic I will be forced to sink your rubber ducky. As much of

 your logic has already has discrepancy holes. BUT!  If I am incorrect on something and after you thoughtfully

 review my point AND if you have a true improvement to my suggestion please post it. Other wise you look like

 you are criticizing just to attack. 



 Barry 	




   Barry, I have not 'attacked' you, nor have I

   suggested any short-falls in your intelligence

   or integrity laced with derisive or pejorative

   prose.



   I have attempted to offer explanations

   of cause/effect/remedy for a constellation

   of failures. Analysis of those failures

   was a prime-directive in my 45+ years at

   Cessna (3x), Beech (2x), Lear, Boeing

   and Electro-Mech (3x) where my work not

   only had to produce beneficial outcomes

   but was subject to review by my peers.



   Recall that this thread began

   with discussions about welding

   in a starter contactor (high pressure, small

   area contacts) due to weak battery

   condition . . . but morphed into

   some discussion about failures in

   battery contactors (low pressure,

   large area contacts) with an entirely

   different failure mode.



   You first stated that the rolled closure

   on the metal housing of a contactor

   was 'hermetic' then you suggest

   there is some value in orienting that

   joint to ward off effects of accumlated

   of 'water and ice'?



   Moisture gets into non-hermetic devices

   with a combination water vapor/liquid

   at the leak site AND a pressure differential

   due to effects atmosphere (weak) or temperature

   (strong). Battery contactors heat up

   significantly while energized. When

   de-energized, a substantial pressure

   differential occurs as the device

   cools. If there is moisture at

   the location of any leak, it is

   sucked inside.



   Drilling the hole in the low spot on

   a contactor cap facing down has two

   benefits. It provides a drain for

   liquid condensate AND a pressure

   relief that stops a cooling contactor

   from 'sucking' moisture across the

   non-hermetic seal at the housing-to-

   cap interface.



   I'm sorry if you feel 'attacked'.

   That's not my mission here. This is all

   about the simple-ideas in physics that

   drive the utility of our favorite machines.

   Ideas that were a foundation for a

   successful career and, I believe, worthy

   of sharing in the OBAM aviation community.

   If I mis-understand something, I'm intently

   interested in knowing it . . . as a teacher

   I have a duty to NOT propagate bad data.

   So I invite you to help sift the sands of simple-

   ideas and forego disparaging remarks.



 

   Bob . . .

trigo(at)mail.telepac.pt
Guest

Posted: Wed Jan 02, 2019 9:13 am Post subject: Relay sticking

Bob



It is more than obvious that you (and everyone else) should not waste our time with this gentleman (Barry) opinions.

Just delete them.

Nothing personal, just by having read some of them.

Have an excellent 2019!

Carlos





No dia 02/01/2019, Ã s 14:16, Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> escreveu:

 	  Quote: 	
		     	  Quote: 	
		    	  Quote: 	
		   	


  or cap facing down with a #40 drain

  hole added right in the center. Now

  trapped liquid had a place to get

  out.

  

 Barry - You must be associated with the Three Stooges...  Remember when they were sitting in a row boat and it sprung

 a leak...  If you have a hole at one end of the boat leaking water in, all you have to do is drill another hole at

 the other end to let the water out! Isn't that correct? That is EXACTLY what you are suggesting.  Also, you did

 not address the issue of having the rolled edge facing Up where water and ice can accumulate. 



 Bob, if you continue to attack me with your warped logic I will be forced to sink your rubber ducky. As much of

 your logic has already has discrepancy holes. BUT!  If I am incorrect on something and after you thoughtfully

 review my point AND if you have a true improvement to my suggestion please post it. Other wise you look like

 you are criticizing just to attack. 



 Barry 	




   Barry, I have not 'attacked' you, nor have I

   suggested any short-falls in your intelligence

   or integrity laced with derisive or pejorative

   prose.



   I have attempted to offer explanations

   of cause/effect/remedy for a constellation

   of failures. Analysis of those failures

   was a prime-directive in my 45+ years at

   Cessna (3x), Beech (2x), Lear, Boeing

   and Electro-Mech (3x) where my work not

   only had to produce beneficial outcomes

   but was subject to review by my peers.



   Recall that this thread began

   with discussions about welding

   in a starter contactor (high pressure, small

   area contacts) due to weak battery

   condition . . . but morphed into

   some discussion about failures in

   battery contactors (low pressure,

   large area contacts) with an entirely

   different failure mode.



   You first stated that the rolled closure

   on the metal housing of a contactor

   was 'hermetic' then you suggest

   there is some value in orienting that

   joint to ward off effects of accumlated

   of 'water and ice'?



   Moisture gets into non-hermetic devices

   with a combination water vapor/liquid

   at the leak site AND a pressure differential

   due to effects atmosphere (weak) or temperature

   (strong). Battery contactors heat up

   significantly while energized. When

   de-energized, a substantial pressure

   differential occurs as the device

   cools. If there is moisture at

   the location of any leak, it is

   sucked inside.



   Drilling the hole in the low spot on

   a contactor cap facing down has two

   benefits. It provides a drain for

   liquid condensate AND a pressure

   relief that stops a cooling contactor

   from 'sucking' moisture across the

   non-hermetic seal at the housing-to-

   cap interface.



   I'm sorry if you feel 'attacked'.

   That's not my mission here. This is all

   about the simple-ideas in physics that

   drive the utility of our favorite machines.

   Ideas that were a foundation for a

   successful career and, I believe, worthy

   of sharing in the OBAM aviation community.

   If I mis-understand something, I'm intently

   interested in knowing it . . . as a teacher

   I have a duty to NOT propagate bad data.

   So I invite you to help sift the sands of simple-

   ideas and forego disparaging remarks.



 

   Bob . . .

nuckolls.bob(at)aeroelect
Guest

Posted: Wed Jan 02, 2019 10:15 am Post subject: Relay sticking

At 11:11 AM 1/2/2019, you wrote:

  	  Quote: 	
		  Bob



 It is more than obvious that you (and everyone else) should not waste our time with this gentleman (Barry) opinions.

 Just delete them.



 Nothing personal, just by having read some of them.



 Have an excellent 2019!

 Carlos

 	


   At last count, there were about 1200 subscribers

   to the list . . . obviously, ACTIVE participants

   number much less but I think it's important to make

   sure that poor or unclear data does not go

   unchallenged. Of course, any who wish

   to bypass the thread are encouraged to do so.



 

   Bob . . .

user9253

Joined: 28 Mar 2008
Posts: 1921
Location: Riley TWP Michigan

Posted: Wed Jan 02, 2019 11:06 am Post subject: Re: Relay sticking

Quote from Official AeroElectric-List Usage Guidelines

 "Feel free to disagree with other viewpoints, BUT keep your tone 

polite and respectful. Don't make snide comments, personally attack 

other listers,"

  If someone posts something that you disagree with, it is best not to quote

 them or mention their name.  Just state the facts about the electrical subject.

Follow Bob's example.  He has contradicted my postings in the past without

offending me.  (Although I do not like to admit being wrong.  LOL)

_________________
Joe Gores

BARRY CHECK 6

Joined: 15 Mar 2011
Posts: 738

Posted: Wed Jan 02, 2019 11:35 am Post subject: Relay sticking

Exactly Joe!



Check your emails, I did not post my response to the gaggle.Â  It was sent directly to Bob.Â  After his snide comments.

So, who is attacking whom?





Barry



On Wednesday, January 2, 2019, user9253 <fransew(at)gmail.com (fransew(at)gmail.com)> wrote:

 	  Quote: 	
		  --> AeroElectric-List message posted by: "user9253" <fransew(at)gmail.com (fransew(at)gmail.com)>

 

 Quote from Official AeroElectric-List Usage Guidelines

 Â "Feel free to disagree with other viewpoints, BUT keep your tone 

 polite and respectful. Don't make snide comments, personally attack 

 other listers,"

 Â  If someone posts something that you disagree with, it is best not to quote

 Â them or mention their name.Â  Just state the facts about the electrical subject.

 Follow Bob's example.Â  He has contradicted my postings in the past without

 offending me.Â  (Although I do not like to admit being wrong.Â  LOL)

 

 --------

 Joe Gores

 

 

 

 

 Read this topic online here:

 

 http://forums.matronics.com/viewtopic.php?p=486660#486660

 

 

 

 

 

 

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

 br> fts!)

 r> > e.com" target="_blank">www.mypilotstore.com

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

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

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

  -

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

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

  FORUMS -

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

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

 WIKI -

 lank">http://wiki.matronics.com

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

 b Site -

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

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

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

 

 

 

 	


-- 

Barry

"Chop'd Liver"

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

cluros(at)gmail.com
Guest

Posted: Fri Jan 04, 2019 2:44 pm Post subject: Relay sticking

Upon examination of the removed starter relay I see that it is a continuous duty relay. It has now been replaced with an intermittent duty relay of appropriate capacity. Thank you for the help everyone but looks like this one was obvious.



On Thu, Dec 27, 2018 at 9:18 AM Robert L. Nuckolls, III <nuckolls.bob(at)aeroelectric.com (nuckolls.bob(at)aeroelectric.com)> wrote:



 	  Quote: 	
		    At 07:14 PM 12/24/2018, you wrote:

  	  Quote: 	
		  We had a strange event last week with our O-200 powered CH750. After running the battery down during a fuel gauge calibration that lasted over an hour, one of our pilots tried to start the engine to taxi back but with the already depleted battery and a less than perfect start procedure they gave up after a couple weak start attempts. I walked over to the aircraft to brief them on a prop start and when I asked for the master on the starter ran. 	


 Â The vast majority of starter contactor

 Â sticking events occur during an attempt

 Â to crank the engine with a weak battery.

 Â The fact that you got immediate starter

 Â action on closure of the master switch

 Â says your starter contactor was 'stuck'

 Â shut.



  	  Quote: 	
		  Â Shut the master off, cycled the start button rapidly a dozen times, master on again and the starter ran again. I could hear the starter relay clicking loudly each time power was applied so it does not seem like there was a physical failure of the relay but more some electrical short activating the relay each time power was applied. 	


 Â Contacts are welded . . .



 

  	  Quote: 	
		  The build team inspected the relay and found a loose connection. Tightening it took the problem from continuous to intermittent; in their words "it's fixed but it did it again once".



 We have removed the relay for replacement, I still think the switch is suspect but they've decided the problem is the relay. Does the aeroelectric list think there would be value in cutting open the relay and examining it? Any suggestions on how best to do so? 	


 Â Go to a car parts store and pick

 Â up a starter contactor that looks

 Â like the one in the aircraft spruce

 Â catalog . . . it will work just fine.

 Â See if the contactor is marked "diode

 Â suppressed" or has the word diode on it

 Â anywhere or on the packaging. 



 [img]cid:1681b04e58bd7b6b1d31[/img]



 

 Â  



 

 Â  Bob . . .

20960049.jpg

Description:

Filesize:

156.73 KB

Viewed:

11460 Time(s)

Display posts from previous:

	Matronics Email Lists Forum Index -> AeroElectric-List	All times are GMT - 8 Hours
Page 1 of 1

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum