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  #1  
Old 04-03-2020, 11:13 AM
FinnFlyer FinnFlyer is offline
 
Join Date: Aug 2018
Location: Bell, FL
Posts: 294
Default How to mount W31- switch/breakers

I looked at the spec sheet of the Tyco W31- series switch/breakers.
It's not clear if the nut against the plastic housing is required.
If not tightened the housing flops around a bit.

I want to mount some of these so that the cylinder is flush with the nut on the instrument panel (visible, user side). Would that require three nuts?

Most of the ten used W31's I bought here only came with one nut.
Anyone have a good source for the 55-001B and/or 55-010B (curled) nuts?

Before posting this, I searched here For W31. They appear prone to failure. Myself, I've had a 10 amp W31 fail open in my RV-3B. Now I'm beginning to wonder if I really should be using these for critical engine/pump controls in an all-electric airplane. I chose them for simplicity, but now I'm worried about reliability. Most things (pumps, ignition coils, injectors and engine controller are redundant -- doubled) but I'm not happy with the idea that switch/breakers are weak links. (I do want some of the circuits resetable in flight.)

Finn
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Last edited by FinnFlyer : 04-03-2020 at 03:36 PM. Reason: Spelling. 5 changed to 10
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  #2  
Old 04-03-2020, 11:18 AM
Raymo's Avatar
Raymo Raymo is offline
 
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Location: Richmond Hill, GA (KLHW)
Posts: 2,156
Default

I purchased a CB/Switch for my single P-Mag while building (dual now). After reading of their failures, I opted to use standard breakers.
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RV-7A - Slider - N495KL - First flt 27 Jan 17
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Catto 3 blade NLE, FlightLines Interior, James cowl, plenum & intake, Anti-Splat -14 seat mod and nose gear support
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  #3  
Old 04-03-2020, 11:41 AM
lr172 lr172 is offline
 
Join Date: Oct 2013
Location: Schaumburg, IL
Posts: 4,892
Default

Quote:
Originally Posted by FinnFlyer View Post
I looked at the spec sheet of the Tyco W31- series switch/breakers.
It's not clear if the nut against the plastic housing is required.
If not tightened the housing flops around a bit.

I want to mount some of these so that the cylinder is flush with the nut on the instrument panel (visible, user side). Would that require three nuts?

Most of the ten used W31's I bought here only came with one nut.
Anyone have a good source for the 55-001B and/or 55-010B (curled) nuts?

Before posting this, I searched here For W31. They appears prone to failure. Myself, I've had a 5 amp W31 fail open in my RV-3B. Now I'm beginning to wonder if I really should be using these for critical engine/pump controls in an all-electric airplane. I chose them for simplicity, but now I'm worried about reliability. Most things (pumps, ignition coils, injectors and engine controller are redundant -- doubled) but I'm not happy with the idea that switch/breakers are weak links. (I do want some of the circuits resetable in flight.)

Finn
Interesting. After three weeks of chasing what I thought was a charging problem, I just found that the Tyco CB (std non-pullable style) was introducing an increased resistance and was causing the EIS to read a lower voltage than actual. So, not sure that std CB's are without issue either. It took me quite a while before I realized that maybe my voltage reading was inaccurate.

Larry
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  #4  
Old 04-03-2020, 11:46 AM
Mike S's Avatar
Mike S Mike S is offline
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Join Date: Sep 2005
Location: Dayton Airpark, NV A34
Posts: 15,118
Default Try Stein

Quote:
Originally Posted by FinnFlyer View Post
Anyone have a good source for the 55-001B and/or 55-010B (curled) nuts?



Finn
https://www.steinair.com/product-category/switches/
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VAF 909

Rv-10, N210LM.

Flying as of 12/4/2010

Phase 1 done, 2/4/2011

Sold after 240+ wonderful hours of flight.

"Flying the airplane is more important than radioing your plight to a person on the ground incapable of understanding or doing anything about it."
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  #5  
Old 04-03-2020, 03:13 PM
FinnFlyer FinnFlyer is offline
 
Join Date: Aug 2018
Location: Bell, FL
Posts: 294
Default Failed W31-

Here a picture of my failed 10A W31 switch/breaker:

http://drive.google.com/open?id=1zJS...Zkp8Xr3OsX0QyY

This looks to me like a design failure. Copper braid broke at the point where it's welded to a contact bar. Compare to soldering a piece if wire to a connector and not providing strain relief further up the wire where the wire is soft -- when wiggling the wire back and forth it will break at the transition from solid to flexible. Only one or two strands shows sign of electrical overload. The rest broken purely by mechanical motion (fatigue). BTW, this 10 amp switch/breaker was used to power an engine monitor (less than 1 amp current draw).

That would be at least one reason for these switch/breakers low rates of "Endurance Cycling: More than 6,000 cycles at 100% of rating, or 10,000 mechanical cycles."

BTW, when it failed, I did contact the manufacturer: "Sorry, expired warranty".

Finn
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RV-4 -- Building
N46AZ RV3-B Mazda 13B EFI -- Bought -- Flying
N993FL RV-3A Mazda 13B NA 575 hours

Last edited by FinnFlyer : 04-03-2020 at 03:29 PM. Reason: I can't get the image to show up! :( :(
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  #6  
Old 04-03-2020, 03:30 PM
Walt's Avatar
Walt Walt is offline
 
Join Date: Aug 2005
Location: Dallas/Ft Worth, TX
Posts: 5,516
Default

Age old problem with Tyco breaker switches, there's an old AD on them as well.

I have piles of these at the shop that I remove, I won't use them personally.
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