This is mainly asking gary as he seems to know what he is talking about
I have some beefy drive motors in anticide now which have been causing a little bit of interferance. What size caps should i use to reduce this, is 10uF enough?
Also going into detail how do these work, as the speed controllers give pulses of voltage the longer the pulse the more speed is outputed, surely these capacitors would see that as noise? Or is this just me not knowing alot about caoacitors. Or is it just the very high frequencies that are cut out. I should proberly know more about this than i do, after doing a year with electronical engineering lectures
Basically the higher the value of the capacitor the lower the frequency it will filter out. !0 uf is way to high at that value it will start to smooth out the speed controller switching and there by increase the dissipation in the output FET's. Try using 10 nf one from each terminal to the case. If you still have trouble you can add a third between the terminals and connect the motor case to the 0v line.
Mr Waller knows his stuff too. He's been doing electronics even longer than me!
The capacitors are only to filter out the high-frequency noise from the motor brushes, so 10nF seems to be the universally-accepted value!
For best results, use ceramic capacitors and make the leads as short as possible. Long leads behave like inductors, and reduce the effectiveness of the capacitors.
Thanks, not sure i will have time to fit them to this version of anticide, that radition loop from the motors can be reduced though. Will see how much it helps
RS have about 20 different types of capacitors. Could you point me in the right direction? i.e the "Ceramic plate capacitor,10nF 63V 5mm" or the "SR15 radial ceramic capacitor,10nF 50V"
Yes! Either will do
The "ceramic plate capacitor" is just that, probably coated in some kind of brown "cement".
The SR15 type is a multilayer monolithic ceramic capacitor (from memory) coated in some kind of resin (maybe) usually yellow AFAIR.
Basically for this application it doesn't matter which type you use. The "ceramic plate" type are probably a little cheaper so I would use those! Look inside a servo and you may well see something similar across the motor terminals.
The most important things are to keep the leads as short as possible and make a decent job of the soldering!
Wow. I have absolutely no idea what is going on.
