grounding the boom

[mk1spitfire]

Your voltage pen was good thinking or research. I'd like to try that. Even if it does lite up I would like to know what 2.4 manufactures have got say about static shutting down their precious interference free microwave technology..

Mk1

[th3tick]

Originally Posted by mk1spitfire

Your voltage pen was good thinking or research. I'd like to try that. Even if it does lite up I would like to know what 2.4 manufactures have got say about static shutting down their precious interference free microwave technology..

Can you really say this is "interference" when what we're talking about is arcing >50V to a ~9V rated receiver? I'd bet many/most Rx manufacturers would say "no" to having that dumping through the bus. It's not radio interference, it's out-of-spec voltage.

[mk1spitfire]

Are you implying that the arc is actually jumping to the insulated reciever or to the exposed tip on the aerial?

[th3tick]

There was a photo around here of one person's burnt antenna tip from the satellite Rx to an AR6200/7000/9000. Thus...

I also wouldn't think the arcing could achieve a frequency anywhere near the 2.4GHz, but, I'm no expert. It arcing to something electrically important just seems a more likely explanation. And with all those nice pins sticking out in space...

[mk1spitfire]

yer i saw that photo2.

Everyones talking of grounding right. What about better insulation.? I mean those aerial tips could easily be protected with some additional heat shrink don't you think?

[alwallash]

On the issue of whether a spark could interfere with a 2.4 GHz rcvr...
An ESD generated metal-to-metal spark can have a current transient with a rise time of much less than 0.5 nanosecond.
This means that there are harmonics will into the GHz range.

When they say they are immune to interference, they mean the lower frequency (say 100 MHz up to 500 MHz) kind of interference from the ESC.
I never believed it would be immune to RFI from a real spark!

With that said, my measurements on a TREX600 showed that lubing the belt reduces the belt trobcharging drastically. I doubt there will be issues with a well lubed belt, as the lube adds conductivity to it.

Even a Van De Graaf generator does not work well in high humidity, due to the adsorbed water vapor layer on surfaces, which adds conductivity to the insulating surface and drains charge.

[HeliBurns]

Do you know that your motor case is not connected to any of it's ESC leads?

But it is connected to the motor mount and the CF frame.

[th3tick]

Originally Posted by alwallash

On the issue of whether a spark could interfere with a 2.4 GHz rcvr...
An ESD generated metal-to-metal spark can have a current transient with a rise time of much less than 0.5 nanosecond.
This means that there are harmonics will into the GHz range.

When they say they are immune to interference, they mean the lower frequency (say 100 MHz up to 500 MHz) kind of interference from the ESC.
I never believed it would be immune to RFI from a real spark!

With that said, my measurements on a TREX600 showed that lubing the belt reduces the belt trobcharging drastically. I doubt there will be issues with a well lubed belt, as the lube adds conductivity to it.

Even a Van De Graaf generator does not work well in high humidity, due to the adsorbed water vapor layer on surfaces, which adds conductivity to the insulating surface and drains charge.

Well, I said I wasn't an expert

I bet you could show "it" if you had a logger on the Rx showing lost frames and such. I have a cable, but in an absence of problems, I'm a lousy tester for this.

As to the lube, wouldn't it be critical what type of lube? That is, I think most folks are using silicone oil of some sort, since it won't eat the belt. Yet silicone oil is non-conductive, I believe. Now the Graphit 33...

Grounding the pulleys still seems the simplest and most direct, as long as you have metal pulleys. Even then, wouldn't just having continuity between the two pulleys be sufficient? For non-metal, the belt may be the only choice.

[HeliBurns]

What about the "reboot" issue? A PCM RX will just drop frames or even go into failsafe mode is it senses RF "jamming"......

Would the 2.4GHz RX's, when they sense RF "jamming", re-boot rather than just drop frames?

[rhone]

there is a carbon track inside the case to!

[psindrup]

Originally Posted by alwallash

With that said, my measurements on a TREX600 showed that lubing the belt reduces the belt trobcharging drastically. I doubt there will be issues with a well lubed belt, as the lube adds conductivity to it.

What did you use as lube? Silicone spray or perhaps Graphite 33?

Thanks

Peter

[Pinecone]

Originally Posted by mk1spitfire

yes, but what tests have you proved to conclude that static shuts down the reciever?

You are proving there is static. No one questionings that or how to over come static by grounding.

In another thread, someone used the piezo ignitor to generate a saprk to the Rx causing shutdowns. Good enough?

[mk1spitfire]

Well thats fact No 1 then pinecone

What aspect of the spark is actually shutting it down?

High voltage and current into the reciever?

The harmonic high frequency noise?

WHAT?

[fugega]

Originally Posted by psindrup

Gabor.
I think you have done an excellent "documentary" here - well done, and thanks!
Peter
PS: And excellent picture quality btw.

Originally Posted by Finless

Gabor, awesome job with the pictures!
This is exactly what I have been describing in many posts about static and why it is important to connect the belt pulleys. It's the belt being isolated that allows static to build it! If you just do the boom the belt will still build potential.

Thanks for the kind words guys.
I learned a lot from here, especially from You Bob. Thanks
Eyefly, great experiment with Your Logo too.

Gabor

[Rob Hair]

As several have said, the key to preventing ESD problems is connecting the ends of the belt (pulleys) together electrically. Several years ago my son and I thoroughly investigated this and made some measurements of the voltages developed. If you're interested, follow the links shown here starting with post # 156:

http://www.rcgroups.com/forums/showt...743294&page=11

[Aberdeen]

Tackel the source,
ground the motor mount the the ESC ground wire via 18 gauge wire.

[miragewsu]

Originally Posted by Aberdeen

Tackel the source,
ground the motor mount the the ESC ground wire via 18 gauge wire.

The source mentioned above is the Belt not the motor. So grounding the motor might not be the cure.

[Pinecone]

Originally Posted by mk1spitfire

Well thats fact No 1 then pinecone

What aspect of the spark is actually shutting it down?

High voltage and current into the reciever?

The harmonic high frequency noise?

WHAT?

What difference does it make?

Sparks cause problems. Stop making sparks, problems go away.

Sparks and electrical equipment never get along. Try opening the case of your computer and generating a few sparks inside and see how it runs.

[Finless]

Guys and to help aberdeen out here too..

There appears to be 2 possible causes for some people that have issues and lets clear the air.

1) Aberdeen has proved that the BEC creates a lot of noise that CAN effect your radio system. I say CAN because not everyone is having the issue. So this means there is a set of circumstances that some people will have issues with the BEC noise. What exactly the combination of circumstances are.... We don;t know. BUT, grounding the negative batter line to the motor mount (the motor can) greatly reduces this noise.

2) Several have proved that static build up of the belt system is a fact. This is a fact for many other helis too not just the 500. Now again I am not having this problem but it appears there is a set of circumstances for some that this static can cause radio and/or gyro problems. What exactly the circumstances are again we don't have the data. BUT grounding the pulleys and boom to the frame resolves this issue.

So bottom line in my opinion if you are having radio shut downs, twitching of your tail, glitches, etc I would go implement BOTH of these fixes. They are simple to do and will save you money!

Bob

[rhone]

amen