MOTOR CUTTING OUT WHEN USING RUDDER

[mike farrellParticipant @mikefarrell21522]

Hi Andrew .I believe Ashley has given you the answer . I ran many combinations of motors and controllers and servos in close contact racing and in the early days and had your problem. The final conclusion was to use a ferrite ring and from that time always used them. I have used one my 1950s cabin cruiser ,just in case. The cost is only a couple of bob so belt and braces.

[andrew greenfieldParticipant @andrewgreenfield50901]

ok i found some on maplins web page . how do i fix them and where do they go . ?

[mike farrellParticipant @mikefarrell21522]

I set a simple loop in the aireal lead close to the reciever . Michael

[ashley needhamParticipant @ashleyneedham69188]

Alternativly, or in addition to, pass the motor wires through one. One wire from one end and the other from the other end.

Any wires that go through the ferrite ring need to do so in a loop, ie one turn or so. its to do with magnetic resonances cancelling each other out or something. There are persons on the forum who can explain or correct me in more detail !!

Ashley

[shipwrightParticipant @shipwright]

There are many textbooks that explain the action of electrical filters. Careful design is required in order to avoid unwanted resonant effects. A simple low pass filter (this is what you need in this application to provide a low impedance path to earth for unwanted high frequency "spikes&quot can be constructed from a coil and a capacitor – the coil is connected to the brushes (one for each brush) and the other end of the coils are connected via a ceramic capacitor to ground. The secret of getting this right is to keep leads as short as possible and to have a good "ground plane". An example of a matched low pass filter is given in "Lessons in Electric Circuits Volume 2 – AC" page 211 http://openbookproject.net/electricCircuits/AC/index.html

…. although I will accept this might be difficult to comprehend if you haven't got the electrical engineering background.

From a practical viewpoint, I have found that the MFA suppressor set of capacitors works OK though an RFC (radio frequency choke – which is what the ferrite ring is) should be fine. Hope that this helps this discussion.

Ian

[Dave MilbournParticipant @davemilbourn48782]

The definitive article is here http://www.modelsoundsinc.com/articles/DavidsOriginalArticles/RFIArticleMarch2006.pdf
Dave M

[shipwrightParticipant @shipwright]

Thanks Dave. That article provides really useful practical advice for reducing RFI in model boat installations.

Ian

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