Motor noise and glitching

[Jules]

Hi all,

I have built 6 or more GB motors so far, but I have been having problems with interferance.
I believe it is EMF from the motors. I have tried 4 different recievers 2 TX's 4 different ESC's and 3 sets of crystals keeping the ariel as far away from ESC and motor as humanly possible.
If I do a range check with the TX ariel down I get about 25 metres with the motor turned off and about 5 Metres or less with the motor running. Also very thing goes dead after alot of glitching at 6 metres away.
Equipment I use is futaba FF8 TX and futaba RX align 10 amp ESC and at the moment a double wired 8 turn in wye turning a 5 x 3 prop.
The mototr runs up fine and I believe there arent any shorts as the motor turns nicely when unpluged, unlike when you touch the wires together and try to turn the motor by hand.
I also noticed that if I turned the motor by hand even very slowly the controll surfaces glitched.
So I tried looking for anything that could make noise ie

1st making sure stator isnt touching the magnets...no probs there.

2nd measuring resistance between stator and bell....found a problem

So as I use brass tube to mount my motors I mounted a spring with a brass contact in the end of it in the tube so it contacted the shaft and the hub. So I wasnt relying on the bearings. Then I used a multimetre to check the resistance and I got a low constant reading.

But to no avail.

I have heard of people using mu metal to sheild ESC's. So my next idea is to do that and also make a sort of firewall around the motor to try to sheild all the EMF sources.

Has anyone else had simular problems????
I am I been really stupid and missing something obvious...
Please HELP........

Thanks in advance,

Jules.

[swatson144]

Metal to metal contacting via the spring? metal to metal is a no no in RC as it causes glitching. even metal control rods connected to metal horns etc.

[Q]

Bearings conduct electricity very well, even closed ones. I have seen people use a bearing to conduct a signal to the main mast in a sub micro helicopter.
Remove the spring from the motor, there's no need for it.

[Jules]

Thanks for your input,

OK thanks for your advice as it didnt make any difference I will remove it.
But please can you suggest a answer to the problem it is not the spring. It is just making a constant earth to stop metal to metal contact or by making a permanent earth or contact between the hub and the stator. You are right maybe the brg doesnt give a good earth but when in use there is always a thrusting force on the brg making the contact. But when the motor was turned by hand it did cause glitching. When I used the multi metre I couldnt get a low ohm reading if one at all before the spring was installed.
I tried alot of combinations before trying that. It was like a last ditch effort.
Any more suggestions would be very greatfully accepted.

Cheers,

Jules.

[swatson144]

I wasn't very clear :oops: but metal parts contacting and breaking contact can cause glitching, even if they aren't used for conducting electricity. Wire control rods and metal horns, metal hinges etc. So I was thinking if you had a plunger held by spring against the shaft and a high spot on the shaft. the resulting contact and breaking could cause your glitching. Pick it up and shake it do you hear anthing rattle?
Other problems could be, and we'll skip the ones involving the parts you have changed.

You aren't Changing crystals on the tx (na for module types), Last glitching problem I helped with was caused by this. Once left on it's original chan and changing rx crystals the problem went away.

Is the motor a secure fit in the brass tube? no rattling?

Are you having problems with all of the motors glitching?

Does it glitch if you hold the motor by its mount? Have an assistant walk off with the TX, if it stops glitching maybe a vibration problem.

does it still glitch with the servos unplugged and only the ESC connected?

Have you tried more than 1 battery pack?

Hmm.. this could go on. Not all your parts could be bad :? So I'm missing some part of the puzzle, It's something in common to all, that you haven't changed yet. I don't really pay too much attention to how close the stuff is on my planes as I have never had a problem with glitching. Usualy all the gear is stuck right beside each other. No problems. So I can assure you that you have an eceptional problem. I don't have an answer, but I sure admire the problem!~

[Jules]

Hi

Thanks for all your help.
I know that metal to metal is a no no.
The only reason I out a sprung earth on the motor was because the servos glitched when I turned the motor by hand. The I checked for continuity between the bell and the stator and I got continuity only some of the time. Knowing that metal contacting on metal can cause glitching I thought that I needed to bypass the brg's as a form of continuity.

The problem isnt as far as I can see the continuity between the stator and the bell ie the brg's causing the noise.

No rattles when the plane is shaken.

The brass tube is a interference fit and is loctited in place.

I have tried two TX's with different crystals in the TX and RX . I brought 2 new crystals but yet again to no avail.

4 of the planes I have built have glitched. The only one that didnt was a twin P-38 and that is only 32 inch span with two ESC's very close to the RX.
The worst is a 18 inch hawk which is a pusher.

I have ordered some mu metal to try shielding each part in turn to find out which part is causeing the problem.

I have also heard that twisting servo wires can stop EMF interference is this true and why... I htought magnetic waves are like sign waves.

AAAAAAAArrrrrrgggggghhhh wish I had listened at school.

Cheers,
Jules.

[Pipistrelli]

Jules,

I have had a couple of glitching problems:

1. I had big glitches using a GWS Pico Rx, so I thought it was because the range was poor, but it turned out to be a Tx crystal in the end. I know you have tried changing this already.

2. What connectors are you using between the battery and ESC and motor/ESC. I first used 1mm pin connectors, but when worn slightly they used to rattle and cause glitching. I now use 2mm gold plated sprung types and the problem is 90% better. I think some glitching is still due to the Rx!

I hope this helps, I know how frustrated you feel, I've been there.

[Q]

Did you try at different locations? Maybe the glitching is caused by an external source, like a motor starting up.

[Jules]

Hi all,

I have been flying in the same location for about one year and havent had problems like this before.

I know that we havent had any construction dont in the last year. Also I dont think we have been suffering from sun spots lately.

I tried changing both crstals and battery and ESC's connectors and that didnt make any difference.

But what I did try was checking continuity between the magnets and the bell and I found that I didnt have any countinuity on two of the magnets so I cleaned the bell and re glued the magnets. Then retested the range and got alomost half the range again. Which is a good start.

As soon as the waether is good I will fly it again and see how many parts I end up with theis time........lol

Wish I had listened at school.....even more.

Cheers,

Jules.