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[TERRY M]

Can anyone help,,, I am having trouble with the electrics on my tug, she is the MMMS Lady Jan. I have fitted a Como/Drill 919 series motor, with a 6 to 1 gearbox running off a 12 volt battery. the motor starts to get a bit erratic when I move away any distance ie less than twenty ft, do I need to fit suppresion capacitors, and if so what type/name ect. My local hobby shop will only sell them with a motor, and a visit to Maplins was a bit of a waste of time, can anyone tell me where I can get these from. She has only been bench tested.
Thanks in advance
Terry m

[HS93 (RIP)]

I f you run the motor at full speed next to you does it still go erratic .?  if it does not, it sounds like it is radio range problems not motor based problems. If you still need them  Action have them .

http://www.action-electronics.co.uk/prices.pdf

Peter

[wombat]

I have a similar problem on Aziz - the motors stutter when it gets away from the shore... But then the supression caps are not really up to snuff and I think it needs a proper antenna. On the other hand you can only tell while the boat is close at hand and it travels happily as far as I want it to - it happily goes as far as I can comfortably see - hence no actio no far

I suggest doing a range check both on land and water - the results could be different. Routing the aerial differently may help especially if it is mostly horizontal (as mine is).

As for the supression capacitors, you want ceramic capacitors with a reasonable voltage rating  (I wouldn't go below 100V) 220nF (Maplin RA50E) between the motor terminals and 100nF (Maplin RA49D) from each terminal to the case.

Wom

[FullLeatherJacket]

Terry
I've sent you a Private Message
FLJ

[malcolmfrary]

Range is governed by the capabilities of the transmitter and receiver, but you have to remember that the receiver picks up everything going.  Interference generated by the motor will join in with the "proper" signal and muck it up.  The receiver basically filters out the unwanted signal by reducing it's sensitivity to everything except the frequency that it is tuned to.  If an unwanted signal is big enough, it will come through on a brute force and ignorance basis.  Signal strength is partially dependent on distance, so, as the motor wiring is usually very close to the aerial, suppression is a must to reduce the noise generated by the motor to manageable proportions.
You also mention a gearbox.  Its never happened to me, but there have been plenty of reports of gearboxes with metal gears generating interference.  Usual cure seems to be to wire all of the metal parts as possible to the battery negative line.

[Doc]

Put the capacitors on the motor.  It may not 'cure' the problem but they certainly will not hurt.  'Malcolmfrary' said it close enough to make enough sense to make sense (how you like that little 'twist' of logic?).  Separating the receiver's wiring from the rest of the wiring does help.  The further the separation the better, although don't expect much separation in the typical boat.  It also sort of helps if multi wire cables are twisted into a sort of spiral (more of that twisted logic stuff, but it does help).  Looping wires through a graphite/iron torroid (sometimes called 'beads') can also help.  Except the antenna/aerial wire, don't do that one.  Where do you find capacitors, torroids and that kind of stuff?  In the UK I have no idea.  Here, the local 'Radio Shack' or electronics parts stores usually have them.  (If you have a few old computer power supplies laying around they usually have several of those torroids in them.)
Capacitors.  The larger the value (within reason!) the more they tend to suppress things.  I'm not familiar with the ratings type you guys use so I'm not going to try to give an example.  Same for the voltage rating of that capacitor, the bigger the better, or at least it won't be as likely to make a loud noise cuz the voltage surges were to high for it.  Three of four times the supply voltage usually works well.
And last but not least... you ready?  Stand the @#$ aerial up and out of the boat!  At least a little.  The higher it is the more range it will have.  All R/C radio is a sort of 'line of sight' thingy.  If the transmitter can't 'see' the receiver's aerial, it isn't happy, and the boat will do what it wants to do, sort of.  That's a little bit of exaggeration, but not much.
None of these things are going to make a huge difference, but they all do make some difference.  Sometimes enough to 'cure' problems.
And lastly AND leastly, there's always the old stand-by solution.  Pound the @#$ thing to bits with a hammer.  Very satisfying...
 - 'Doc

[malcolmfrary]

The fairly universal source in the UK is Maplin, who started being like radio Shack and now seem to be trying to become toys r us, but still do"proper" discrete components for now.

Another thing with range is that the transmitter aerial is not a gun barrel.  The signal does not come out of the end, but more sort of sideways.  Pointing it at the offending boat does little except ensure that minimum propagation heads that way.
I only do it when the boat has conked out and is near enough to snag and I havn't got another stick.

[TERRY M]

WOW,,,Thankyou guys for all the info, I will have to re-read and try to digest your answers.
Wombat I will have another look in Maplins tomorrow, they are open I believe on a sunday, at least I wont look like a dummy when I ask for the suppresers now.
FLJ,,, thanks for the PM and link to your site, I will be back and order a few things I will need for other projects, if you get an e,mail from an idiot who has no idea about electrics you will know its me.
Malcomfrary, thanks for all the advice.
Doc,,, I will be sure to keep the hammer handy,

many thanks
Terry m

[wombat]

Also worth bearing in mind that Farnell do credit card orders over the web (www.farnell.co.uk), I think that RS do as well (www.rswww.co.uk). From these two suppliers, you can probably get pretty much what you need.

Wom

[gribeauval]

'Found' this picture at Fast Electrics to help out with the explainations.

[TERRY M]

Hy Guys.
Once again many thanks for all the great advice, I went to Maplins yesterday and bought the suppresers as advised by Wombat (it is suprising how helpfull they are when you have the right codes for them to find things) I have fitted them to the motor and everything is working great, I can leave the boat in the shed and walk into my kitchen area and the motor runs perfect and isnt showing any problems. I did find it difficult to solder to the motor caseing as it seems to be aluminium but I did get a tack, how long it will hold is anyones guess, so once again many many thanks.
Terry M

[Doc]

Terry,
It was your thoughts of that hammer that did it.  Boats are mind readers, and it got worried when it saw how appealing the hammer thingy sounded.  Gotta out think them @#$ things!
 - 'Doc

[HS93 (RIP)]

A tip for soldering to motors , get a small grinder or file and clean the spot you are going to solder first ,THEN use a big iron ,if you don't have a big iron use a lump of copper held in mollies will do , heat it on a gas cooker /flame .You have to heat it quick so as not to damage the motor.flux is a must I use "BAKERS FLUID" acid it is so hand ,if you do brass work it is a must as you have less problems painting afterwards. Motor cases are normally plated and that is what causes the problems.

Peter