Radio interference or esc problem ?

[setecastronomy]

Yesterday my crawler moved its first steps but I had some problems with the electronics. My esc is a Novak xrs, largely used for crawlers.
There are 2 small leds on it and the red one is on in neutral, the green one is on when in full throttle while it blinks when in full reverse.
The weird behaviour is the following: applying full reverse throttle truck makes a small jump backward, then it stops. I thought it was due to radio interference and to the fact the antenna was sunk inside
the chassis but I noticed that the green led was blinking on the esc as during normal reverse functioning. Also applying full forward throttle there were problems because the truck moved with small
jumps as obeying a relentless full throttle-neutral sequence. Any idea ?
Perhaps it was due to low batteries, I doubt, but I will verify.

Thanks
Filippo

 

[DaViolentOne]

Could be low batteries, yes, or, it could also be something as simple as antenna routing... Does your antenna cross itself, touch any aluminum or carbon fiber? If any one those you can answer yes to, then ya got issues...

Antenna wires should NEVER cross itself, that'll create glitch noise and it should never be against any metal or carboin composite as both are capable of carrying a current and will create readio noise between the part and the antenna wire...

Could also be that you have no capacitors on yer motor.. I found out the hard way that putting caps on a motor will stop the twitches and so on...

Check for those and see if that helps any..

 

[Spucknit]

I had the exact same problem with my xrs. It worked fine when I had an axel snapper motor, but when I changed to the integy55t it started lurching exactly as you described. I chaged recievers and the problem continued, put in a RX pack and it didn't help either. I never tried caps because the xrs manual said specifically not to use them. All I could figure was that it was just the cheap ESC. I bought a mamba max, problems solved.

 

[DaViolentOne]

I had the exact same problem with my xrs. It worked fine when I had an axel snapper motor, but when I changed to the integy55t it started lurching exactly as you described. I chaged recievers and the problem continued, put in a RX pack and it didn't help either. I never tried caps because the xrs manual said specifically not to use them. All I could figure was that it was just the cheap ESC. I bought a mamba max, problems solved.

Actually, the manual says to not use a Shotkey Diode, as those are used on non-reversing systems... Nothin' about caps other than "using them will help prevent giltching" at least that's what my XRS manual says..

 

[Spucknit]

It looks like I miss understood the manual :-(, I would defanitly try caps then.

 

[setecastronomy]

Surely I have to improve my antenna. I first mounted the antenna on a mircro rs4 (old touring car in the 1/18 scale) placing the wire in the plastic pipe and making concentric circles with the excess wire. When I removed the radio from the micro rs4 I was lazy and didn't re-arrange it, so now the antenna tube lays horizontally inside the tvp chassis.
I saw some photos of other crawlers where the chassis has some holes to sustain the antenna wire, inserted in a fuel tube, which crosses the chassis more times. Others have made lots of holes in a tiny lexan rectagle and the antenna wire zig-zag on it. Which is the best solution ?

About the capacitors: I have a very cheap tamiya sport tuned motor, it doen't have capacitors outside but I think they are inside it. Am I wrong ?
Otherwise what kind of capacitors can I mount ? Have I to triangulate them?

Thanks
Filippo

 

[DaViolentOne]

I use a zap-strap/zip-tie as an antenna holder... On my Clod, the strap's glued to the box the ELX are in then wrapped around the strap to the top... For my TLT, the strap's taped to the side of the RX and the wire is agsin wrapped around that... I did the TLT RX that way 'cos I use the RX in 2 other RC's as well and it's rather portable... My TT-01 and TA-02...

I've seen ppl do the lexan thing a lot of times here on race rigs... Letting your antenna lay flat like you mentioned doesn't allow for much signal to get to the antenna... If you plan to use the RX in more than 1 RC, then you can make the antenna holder part of the RX to save wrapping the wire everytime you put it in another RC...

If you want, I can take a pic of it today and post it up so you can get a better idea...

 

[setecastronomy]

After a long period of inactivity I'm back.
I want to highlight again I'm using a Novak XRS and two servos powered by the BEC.
On Saturday I took my crawler and when to the river, but I was overwelmed by radio interferences. I made some investigation and found out the following:
1) sometimes the servo cannot move the wheels. The servo asks for current and the bec on the esc starts heating and sometimes the esc stops working (I suppose due to overheat). Can it cause interference too ?
2) I moved the antenna and the receiver in different position and finally I put them out the truck, but the radio interference where still there.

Here is the description of what I have called radio interference and probably are something else:
-pushing full throttle the truck behaves like a series of full throttle and stops.
-pushing reverse throttle the truck makes a small jump backward and then it stops until you release the throttle.

I'm using a R2 tranny which has all metal gears. I learnt that metal gears can cause interference.

I made some test with a smaller motor in my hand (so without any load ) and it moved flawlessly forward and backward.
Can the stops of the motor be due to short circuit protection on the esc ?

So I don't know where the problem is:
worn brushes in the motor ?
esc failure ?
low cost receiver ?

Any advice ?
Thanks
Filippo

 

[konafreeride11]

try and get your reciever as far away from your motor as you can the spining brushes cause a frenquency that will mess with some radio and recievers.. I THINK :roll:

 

[cartronicshn]

Maybe check your servos? if you have a bad servo it may cause glitching, also i had some major problems once when i bought a bunch of Yeah racing fm crystals for one of my radios, the cars they were on started glitching, swapping them for the stock units cured the glitching

 

[smokinubyrc]

the xrs cant handle two servos on its own thats half your problem drop in a rx pack and remove the red wire from the esc to the rx!
that should solve your overheating and bec issue, it might even get rid of the glitch but you need to put three caps on the motor!"thumbsup"

 

[setecastronomy]

Watching other people crawlers I don't see the battery pack for the servos. Is there an ESC I can use with a BEC so robust to power two servos ?

About the capacitors: which is the correct size and type ?

Thanks
Filippo

 

[Jeeper Creeper]

I use Novak Super Duty or Super Rooster and Tekin Rebel 2 and all work good for 2 servos with no receiver pack.

You need three 0.1 uf capacitors for each motor

http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXUE61&P=7

What type of frame do you have? Is the R2 mounted to metal or delrin? Make sure it is isolated from the metal frame. I had a TLT that glitched so bad it was undriveable. After trying everything I ended up getting a 100% delrin "Thunderhorse" and the glitching went away totally.

 

[setecastronomy]

I have an aluminum tvp chassis with some holes for the screws which go to the R2. So there is electrical conductivity between the frame and the R2. If you suggest to isolate the R2 I don't know what kind of materials to use. How can I isolate the screws that touch the chassis with their head and fit into the R2 ?

Thanks
Filippo

 

[Jeeper Creeper]

I don't have an R2 but I believe that you can either screw into the side or the bottom. If you are screwing into an aluminum side plate, I would recommend that you screw into the skid plate. If your skid plate is metal then you need to replace it with a delrin one. You may have to make your own. I have heard of people making them from cutting boards. For now, you can test it by unscrewing your tranny and isolating it from any conductive material using some plastic or rubber and then duct tape the tranny onto the frame and run it around slowly.

Hopefully, your rig will be glitch free. If not, look into replacing the ESC and or receiver. It really is a trial and error process. Good luck.

 

[hitman46mod]

The issue with the trans can be solved by making a gasket with tape between the motor and the trans."thumbsup"