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-   -   How to mount W31- switch/breakers (https://vansairforce.net/community/showthread.php?t=181032)

FinnFlyer 04-03-2020 11:13 AM

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

Raymo 04-03-2020 11:18 AM

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.

lr172 04-03-2020 11:41 AM

Quote:

Originally Posted by FinnFlyer (Post 1419334)
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

Mike S 04-03-2020 11:46 AM

Try Stein
 
Quote:

Originally Posted by FinnFlyer (Post 1419334)
Anyone have a good source for the 55-001B and/or 55-010B (curled) nuts?



Finn

https://www.steinair.com/product-category/switches/

FinnFlyer 04-03-2020 03:13 PM

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

Walt 04-03-2020 03:30 PM

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.

DylanRush 11-05-2020 01:12 PM

I just installed a new one of these in my panel. As I was rewiring, a 20 year old old Tyco circuit breaker started physically falling apart. Some plastic feel down to the floor. It still works, but I ordered a replacement for that one too.

Now I'm a little spooked about these circuit breakers. They are dead simple to replace; should we just replace them every 5 years or so? Is there an alternative that is more durable and shares the same form factor?

dlloyd3 11-05-2020 02:09 PM

Yes, there is a 20 year old AD involving the W31 series in certified aircraft. I sold my Bonanza right before the AD came out. Had 8000 hours on it and in all that time, only one breaker failed. Landing light breaker/switch got a little hard to use, then became unuseable. Think it had about 5600 hours at the time. Only other time one failed was getting in the RV and caught my pants leg on the fuel pump breaker/switch. Bat handle broke off. I did have a couple Klixon switches fail in a Mooney with a lot less hours.

FinnFlyer 11-05-2020 03:46 PM

Frequency of use
 
Quote:

Originally Posted by DylanRush (Post 1475323)
I just installed a new one of these in my panel. As I was rewiring, a 20 year old old Tyco circuit breaker started physically falling apart. Some plastic feel down to the floor. It still works, but I ordered a replacement for that one too.

Now I'm a little spooked about these circuit breakers. They are dead simple to replace; should we just replace them every 5 years or so? Is there an alternative that is more durable and shares the same form factor?

I really think it's a question on how many times the switch is flipped (off/on).

It's like a piece of wire: how many times do you have to sharply bend it back and forth before all strands are broken.

Finn

BlndRvtr 11-10-2020 01:31 PM

Are the Honeywell switches constructed differently so as to be more durable?

George


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