What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Wire bundles

M

Maxrate

Well Known Member
Patron
I read the recent thread on how to run the elevator trim wire. After talking with an AP friend he says to take and twist the wire or braid it as you would a little girls hair. Since I have two boys I don't have a lot of experience with the latter so I thought there may be some good pics out there. For instance the elevator trim runs a good 18ft to the stick or panel. When I tried to twist that length well, :confused:

Thx,
 
easy fix

I wouldn't braid it but you can twist it easily. Put an eyelet in your cordless drill. Tie the wire to the eyelet and fix the other end to something. Slowly twist the wire.

Or, you can buy the pre-made 5 wire bundle for the purpose. Much easier.
 
What I did was to

clamp one end of the required length of wires plus about 30% in a vise. Chuck the other end in your drill. Back up till the wires are taught and run the drill until the wire bundle takes a "set". Worked for me. I bought the autopilot bundle from Stein when I got to that point. Worked great.

Good luck :D
 
Braiding does not twist the conductors so there is no cancellation of induced noise.
Click to expand...

I could be missing the obvious but why do you say braiding does not twist the conductors? If you can't braid, how would you twist 3 wires together, the center of the 3 would not get twisted unless you braid.
 
647jc said:
I could be missing the obvious but why do you say braiding does not twist the conductors? If you can't braid, how would you twist 3 wires together, the center of the 3 would not get twisted unless you braid.
Click to expand...

If you braid then you are likely to induce noise into one the three wires. Read the Wiki link I posted above in post #5. Twisting pairs of wires together as done in a cable has to be done in a very controlled way and has been done ever since the telephone was invented. Putting a twist in a pair of wires will cancel out some of the noise that induced into the pair from external sources. It is only good to twist pairs of wires together that are associated with each other. For example the pair of wires to a trim motor or the pair of wires to a strobe or a nav light. It is a good idea to use different number of twist per foot for each pair. If the same number of twists are used then noise from adjacent cable with the same number of twists is more readily picked up.
 
Anthony,

Actually I did read the Wiki link you posted and did not see where they stated braiding did not twist the wires. Actually I couldn't find any reference to the word braiding in the write up but maybe I just missed it.

I understand the theory and practice of twisting wire pairs to reduce transmission and reception of EMF but don't necessarily understand why braiding would not achieve similar but perhaps less effective results.

This thread started as a question relating to trim control wiring. The most common although not typical problem encountered with the electric trim system is noise induced into the position readout circuit resulting in a flickering readout or perhaps multiple bars being illuminted all at the same time. The position readout is basically a volt meter implemented via an LED bar graph readout and a single controller / driver IC. There are 3 wires going to the Servo position potentiometer from this controller IC. One wire is ground reference, another is positive reference or source or bias voltage and the third is wiper voltage. The IC basically reads and displays the voltage present at the wiper in reference to the supplied ground. The currents used in this circuit are quite low and it is easy to induce noise into the circuit. Ideally you should shield this circuit and try to keep it away from possible sources of noise. As a possible fix to an existing problem where shielded wire was not used, some recommend just twisting or braiding the 3 conductors used by the position readout circuit. Since simply twisting 3 wires together results in one wire not getting twisted in relation to the other 2 wires, braiding would seem to be a better solution. At least each wire in the braid would get twisted in an alternating pattern with each of the other 2 wires. A 3 wire braid could probably be described as an alternating twist pattern.

In defense of my possible ignorance, I'm not an EE or physics major so I could be completely off base, wouldn't be the first time :eek:
 
Let me see if this helps. It's been a long time since I saw my daughters hair braided but if I remember correctly there wasn't any twisting of the hair around its self as in the twisted pair diagram. The hair isn't wrapped around its self but positioned left to right to left to right. Does that make sense? Now, all bets are off if you are talking about a French braid. I've never figured that one out on wife or daughter.
 
OK, I think I see the picture now. I sure thought a basic flat braid would include twisting wires in relation to one another but apparently not so. I did find a good image of the braid process which convinced me.

Braid_StepBystep.jpg
 
You must log in or register to reply here.
Back
Top