Model Boat Mayhem
Technical, Techniques, Hints, and Tips => DC Motors (Brushed) and Speed Controllers => Topic started by: catman on March 28, 2007, 07:53:39 pm
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HI..
I have a graupner speed 700 bb turbo 12v motor, this came with 2 capacitors both 47 nf. when i bought the motor i asked for a suppression kit which is by MFA and has 2 capacitors 0.1 mfd and 1 capacitor 0.22 mfd. which set of capacitors should i use?
any help would be gratefull.
mike.
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:)Hi, I have used the MFA ones on most of my models and on one powered by a 700BB turbo with no probs, just put them on as instructed on the packet...Also use heat shrink tubing on the leads ...so they don't have any chance of shorting out on the casing end.. ;D
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I get the impression he's confusing those capacitor 'sets' as a possible 'option'. It sounds like he's thinking either to use the two 473's OR just the one 224 cap.
Maybe the instructions are saying to use all three.
Shan't insult the intelligence of them who know already, so there's no need to go into all the bumph again. Take a sail through the back-post of these 'Electrics & Electronics' pages. The full 'how-to' is already there.
Being that it's a Speed 700, I wonder what would happen if they supplied a 104, instead of the 224?
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Please see this page for instructions on motor suppression. (http://www.modelfireboats.co.nr/ue/motors/suppression.html)
The rules are that you use all three capacitors and the 47nF capacitor goes accross the two pins and the others go from the pins to the outer casing.
Stephen.
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Thanks for help guys.
Going to use the mfa set, not confused if they are an "option" just wondered if the ones supplied were better than the ones from MFA.
can anyone recommend a throttle rudder mixer that would work with 2x mtronik viper 20 marine ESC going to 2 speed 700 BB turbos
12v.
Newbie to boats so be patient. javascript:void(0);
Grin
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Just for 'grins'...
Almost any size capacitor will work. To some ridiculous point, bigger is better. The only thing to really be careful about is the capacitor's voltage breakdown rating. That should be at ~least~ twice whatever voltage is normally applied to the capacitor (another case where bigger is better till it's just too big to fit). What happens if the capacitance isn't large enough? Not much suppression. If the voltage rating isn't large enough? Loud noises and no more capacitor. Two of the things you should watch for when messing with "cow-pastures"...
- 'Doc
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And if you go for big ones....Don't touch the ends......... 8)
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I would re-iterate, as someone lese has pointed out that you want to use ceramic capacitors for supression. You can get loads of capacitance in a tiny little space if you use different types, but you can find that they will not actually suppress as they cannotdeal with the frequencies.
Unless you are not reversing avoid polarised capacitors like the plague (especially tantalum capacitors as they go "FOOM" spectacularly with pretty coloured flames)
Wom
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Thanks for help guys.
Going to use the mfa set, not confused if they are an "option" just wondered if the ones supplied were better than the ones from MFA.
can anyone recommend a throttle rudder mixer that would work with 2x mtronik viper 20 marine ESC going to 2 speed 700 BB turbos
12v.
Newbie to boats so be patient. javascript:void(0);
Grin
Catman
ACTion, Astec and Hunter Systems all make mixers which should work with your Mtronik ESCs. I've always used ACTion myself, but that's not to say the others aren't as good. If you want more gen on mixers then click on the following link to the main Mayhem website:
http://www.modelboatmayhem.co.uk/Common/Electrics/Twin_motors.htm
BTW ACTion also do a motor suppression set!
Suit yourself.