lownslo

I am basically electronics illiterate. I have 2 sources saying different choices for capacitors for my brushed motor. This motor came in the Sea Queen kit. The book says it is a Caldercraft motor, nominal voltage 12 V, operating range 6-24, (I am using a sealed 12 V batt.). No load current (A): 0.4, Current at nominal voltage (A): 5.0, stall current 20.3 Amps. The ESC directions, a MTronics Viper 20, say there is no need for a capacitor between the + and - posts since this model has reverse. OK....... They say to use 2 motor capacitors, (0.1uF).... one from the negative terminal to the can, and one from the positive terminal to the can.
The other fairly reliable source says to use (2) capacitors, (as above), to the can, but use .047uF (Micro Farad).[] Since I have no idea about this, can one of you fellas that is an electric guru help?
Thanks in advance,
lownslo (Sloboat Bob in Indy)

AndyKunz

The ESC manual is correct.

If you put the big cap between the leads, it will go bang as soon as you reverse. You could safely use a third one of the small caps but it's really not necessary.

Andy

rblubaugh

My Feedback: (5)

O.K. Andy, I thought the idea of the capacitors was to reduce/eliminate RFI/EMI noise for the radio receiver. You'll have to explain a little more for me please. Do you need the caps or not? If so, what size? Thsi is with a system using reverse of course.

Thanks you

Bob, a different one

lownslo

Andy,
If I read your post correctly........ the "big" cap between the + and - post will make it go BANG in reverse. I am assuming you mean it will blow out the ESC. By big ..... I am again assuming the 0.1 cap, and the small one being the .047 cap. I have no problem with eliminating the cap between the + and - motor tabs. In fact I mentioned in my original post that Mtronics directions say: because it has reverse, DON'T use cap between the motor tabs. My concern, (because of my ignorance in eletronics), is WHICH cap should I use from the + post to case .... and -post to case? .... The .047 uF or the 0.1 uF?
lownslo

AndyKunz

You can use EITHER cap from tab to case. It doesn't matter much, but I would then to use the .1uF because I have bucketloads of them.

I mis-read your sizes - usually they put a big electrolytic cap between the tabs. You can't do that with a reversing control. THE CAP would go bang, the ESC wouldn't know it was there. An electrolytic cap looks like a miniature Coke can with wires sticking out, and one wire is + the other -. Since you don't have one of those, skip my earlier comments.

All the caps do is take out some of the electronic noise from the motor commutation. They are really poor circuits for that, but better than nothing.

To summarize, use either .047 or .1 between either plus or minus tabs (one cap per tab) and the motor case.

If you google, you can find lots of examples on how to do this on the web. The Rum Runner and Offshore Electric sites should be particularly helpful for wiring diagrams.

Andy

lownslo

Thanks so much Andy,
That is what I needed to know
lownslo