Model Boat Mayhem

Technical, Techniques, Hints, and Tips => The "Black Arts!" ( Electrics & Electronics ) => Topic started by: lib435 on January 10, 2010, 08:22:30 pm

Title: motor suppression and 2.4ghz
Post by: lib435 on January 10, 2010, 08:22:30 pm
Hi all, been flying helis for about nine years and using spektrum gear for about the last three and have now decided to dabble here. Started to build my 1st springer last night and got thinking.
If I am using 2.4ghz do I still need to suppress my 540 motor as I have heard that the noise spektrum is well below the 2.4ghz level. I have done a search here on the forum and there were a couple of posts from a while ago that agreed with this. Has anyone tried 2.4 with an un-suppressed motor? What were the results?
Many Thanks in advance,
Graham  :-)

p.s. Ive also posted this in the electrics section as well.
Title: motor suppression and 2.4ghz
Post by: lib435 on January 10, 2010, 08:23:28 pm
Hi all, been flying helis for about nine years and using spektrum gear for about the last three and have now decided to dabble here. Started to build my 1st springer last night and got thinking.
If I am using 2.4ghz do I still need to suppress my 540 motor as I have heard that the noise spektrum is well below the 2.4ghz level. I have done a search here on the forum and there were a couple of posts from a while ago that agreed with this. Has anyone tried 2.4 with an un-suppressed motor? What were the results?
Many Thanks in advance,
Graham  :-)

p.s. Ive also posted this in the electrics section as well.
Title: Re: motor suppression and 2.4ghz
Post by: craftysod on January 10, 2010, 08:42:16 pm
I use the spektrum,and none of my motors are suppressed,
no problems so far
Title: Re: motor suppression and 2.4ghz
Post by: dodgy geezer on January 10, 2010, 10:03:17 pm
If I am using 2.4ghz do I still need to suppress my 540 motor as I have heard that the noise spektrum is well below the 2.4ghz level.

Radiated spark noise is probably well below 2.4GHz, but that's not the only path for interference. It can come down the motor lines into the speed controller and receiver.

I've just been running a small brushed motor (about 3 cm long) with a cheap ESC and 2.4Ghz receiver. Small motors like this are pretty bad for sparks. I tried it without suppression and the servo went everywhere - then I put 0.1mf capacitors acros the brushes and to earth, and the interference died away completely.

If you have a lot of line noise, a ferrite inductor on the line may help...
Title: Re: motor suppression and 2.4ghz
Post by: Bill D203 on January 11, 2010, 03:02:31 pm
Hi I run a Springer on Futaba 2.4. I have caps fitted on my 540 motor. As they are only Penny's to buy i fitted them anyway.
Title: Re: motor suppression and 2.4ghz
Post by: des321 on January 11, 2010, 05:23:08 pm
I just finished a Springer using an MFA 540 motor. Initial setup was on 27mhz and I had some problems. I changed it to 2.4ghz and have no problems at all. I now nothing about electronics. Everyone at my club was saying to fit Resistors and Capacitors which only cost pennies. Fine but if you have no idea what to buy or where to fit them its not much help. My intuition said try 2.4 and it worked.
Title: Re: motor suppression and 2.4ghz
Post by: FullLeatherJacket on January 11, 2010, 08:07:39 pm
Wombat and I recently tested a software update on one of our ESCs, using a MFA geared Torpedo 500 on 12v and a Futaba 2.4 6EXA. These motors are supplied with just one capacitor across the terminals. Under power it kicked and sparked like a very angry thing, so Tim fitted a couple of 0.1uF ceramics between the brush terminals and the case. Fixed it totally.
I'm always amazed at the reluctance of folk to fit suppressor caps (NOT resistors!). Even if you actually don't require them it's worth a few bob to fit them anyway and eliminate one potential source of tremendous irritation. No knowledge of electronics is required................honest!
Suit yourselves.
FLJ
Title: Re: motor suppression and 2.4ghz
Post by: Bridkid on January 11, 2010, 08:24:09 pm
Me too Graham. I have 2 springers, a Huntsman and 3 fast electrics all on spektrum 2.4 with no motor supression......no problems so far.
Cheers,
Ian.
 8)
Title: Re: motor suppression and 2.4ghz
Post by: andygh on January 11, 2010, 08:50:52 pm
I just fit caps as a matter of course, I might need to change radio from 2.4 to 40 or whatever in the future. It's so cheap & easy it's not worth leaving them off
Title: Re: motor suppression and 2.4ghz
Post by: Aurigarius on January 11, 2010, 08:52:30 pm
Graham I was actually testing this in my RC-Car some time ago.
2,4ghz is less prone to glitching than 40 or 27mhz. But it still can have glitches. But normally it has a built in fail-save function saving your model. But that doesn't mean it saves other models with 27mhz that may be near your boat. They still can be glitched by YOUR boat.

So please put at least one cap on (better three)
It is not much work, really
Title: Re: motor suppression and 2.4ghz
Post by: des321 on January 11, 2010, 10:11:40 pm
Forgive me, but if its so simple (to those that know) and low cost to fit the required suppression to the motors why don't they come already fitted? I suppose the answer is they are are made in massive volume and our model boaters relatively tiny demand doesn't merit a special suppressed version. Perhaps our highly knowledgeable and customer friendly model boat suppliers could oblige?
Title: Re: motor suppression and 2.4ghz
Post by: malcolmfrary on January 12, 2010, 10:06:32 am
Some motors do come ready fitted.  They tend to be the more up-market ones, with a price to match, and are thus less popular with cost-conscious newbies.
Having said that, it is not unknown for any component to fail, not always after a long life.  The single capacitor fitted to FLJ's motor MIGHT have been a broken one, fitting the two from brush to case might well have created the one good one it needed.
The previous point about interference being fed through the wiring around the non-radio part of the circuit should be considered, as should the possibility of one unsuppressed model adversely affecting other models.
Title: Re: motor suppression and 2.4ghz
Post by: dodgy geezer on January 12, 2010, 12:04:44 pm
I suspect that a lot of the difference in reported interference rejection is due to the quality of the equipment used...
Title: Re: motor suppression and 2.4ghz
Post by: FullLeatherJacket on January 12, 2010, 01:41:13 pm
Forgive me, but if its so simple (to those that know) and low cost to fit the required suppression to the motors why don't they come already fitted? I suppose the answer is they are are made in massive volume and our model boaters relatively tiny demand doesn't merit a special suppressed version. Perhaps our highly knowledgeable and customer friendly model boat suppliers could oblige?

You are spot-on with your analysis of the market and why us boaties are "ignored". Heck - if we can't obtain proper boat radio sets then we sure as hell won't get iinternal suppressors fitted to cheapo motors. Do you know how many motors Mabuchi, Johnson and Sun make between them in a day? It's millions. Unless the power-tool manufacturers want suppressors fitted to these motors then they won't be.

As far as us customer-friendly suppliers are concerned, much the same logic applies. Sure - we could  fit external suppressors to all the motors we sell, but it would increase the cost and not many people like paying for something they can easily do themselves. I repeat - it takes no knowledge of electronics to do this job; you just follow the little drawing which comes in the packet.

Suit yourself.

FLJ
Title: Re: motor suppression and 2.4ghz
Post by: lib435 on January 12, 2010, 01:56:55 pm
Hi All, Many thanks for all the replies and although in general there seems to be no real issues I think I will fit suppression to my motor as many have pointed out it is cheap to do and should eliminate any possible future issues not just for me but for other modellers as well.
Graham. :-))