Do you really need capacitors on Johnson 540's?

[tamiyadude]

I've always wondered about this. I read one time that those johnson and mabuchi motors actually have built in capacitors. I think one place I read that was the Tamiya guidebook a couple of years ago. I'm going to be using the Johnson 540's that came with my dagger kit for awhile with my novak super rooster esc and Futaba mag jr FM. I know Novak says three of the .01 microfarad caps on each motor, but didn't know if it was really necessary on the Johnsons. Anyone know?

I was going to run them without caps and see if I got any glitching, but I didn't want to do anything harmful to the esc or radio gear. I'm almost positive I read those closed endbell motors have built-in capacitors, but I don't know what their value is.

I've been putting caps on those closed endbell motors for 14 years.. but it's not my favorite thing to do in life. I don't mind it on open endbell motors near as much :D

Anyone know?

[shadmaster4]

it is just to help prevent glitching. If you dagger doesn't have much graphite, just an AM radio would work. It won't harm your esc/radio if you don't have caps on, but its always a little better to have them on, even though i can;t tell much difference.

[InspGadgt]

I busted open a Mabuchi this weekend and can confirm they do have 2 capacitors installed inside them. So at most you should only need 1 additional capacitor if you are running with a transponder. FYI for those of you who were wondering...the Sport Tuned Mabuchi motor is 22 turns.

[tamiyadude]

are those internal caps .01 microfarad though??

[tamiyadude]

c'mon experts.... chime in :D

[TEM]

Tamiyadude; I don't think it matters whether or not they are exactly a certain amount. Besides; it's a silver can motor we are taking about. There is some electrical noise generated by the arcing between the brushes and commutator. Those little caps are used to reduce that noise by shorting some of it out(yes, some; the ones at the right frequency). If you are not glitching, etc; don't worry about it.

[tamiyadude]

I would think the value of the caps matters. The .01 microfarad are for high frequency speedos and some others like the .47 microfarad were for low frequency speedos. Ever notice the Mabuchi motors that Traxxas sells as "stingers"? Traxxas has soldered external caps on them that are for low frequency speedos like their own XL-1. Which always made me wonder why they did that because if those motors supposedly do contain built-in caps, my guess would be low frequency just because the design has been around since before high freq. speedos.

[tamiyadude]

Originally posted by TEM
If you are not glitching, etc; don't worry about it.

If you read my question in the original post, it says "I've always wondered". Not "I've always worried" :rolleyes:

With all the knowledgable members we have here... figured someone would know. I've seen more difficult questions answered... :D

[InspGadgt]

well even before with low frequency ESCs we used 2 .01mf and 1 barrel .47mf capacitors. I've ran many mabuchi motors with my antenna under the body and no glitching so if it's not .01 it's close enough. As for the Traxxas motors...those are a 20T motor so it's internals are allready different then the Mabuchi motors. I'm not positive but I think they are a Johnson can motor of some sort.

[tamiyadude]

I bought a couple of traxxas stingers off ebay awhile back... under the stinger sticker there is a mabuchi sticker... RS540-SH if I remember correctly.