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View Full Version : Comm drops or run it dry?


Bung-drew
2011.09.30, 09:52 PM
So I have decided to stop using comm drops on my silver brushed PN 70 turn motor after reading about what comm drops will do to the silver...:eek: is it still necessary to apply oil to the bushings or is it okay to run it dry? I recall the motor will be kinda noisy though if dry...

chad508
2011.09.30, 10:03 PM
i run the comm drops on the bushings. i dont like to use oil on the end bell due to it running down on the comm and causing more problems. as far as the comm drops on silver brushes i would not worry. they are not going to last long anyway.

rock hard
2011.09.30, 10:10 PM
What did you read about silver?
not all silver brushes are "high" silver,for example in the 540 world the trinity xxx silver brushes are often thought to be pure silver,but the xx has carbon,which acts as its own lubricantr for the comm.

I ppersonally do not oil my comm,but in this next quote,big jim recomends it,
however remember this quote was after his origunal comments that oil was bad for silver... there had been advancements in petrolium producst.,especially in the synthetics and thats what appearently changed his opinion.and there have been even greater advancments since then.

but,most brushes of today (in the motors I have dealt with) there is no need.

A special note from BIG JIM:</u> Since these original posts from the Team RCV forums, the Tribotech Company, the makers of the oil additive mentioned above, have released their own formula of commutator lubricant especially made for R/C motors. Their formulation far exceeds the usefulness of any automotive oil additive for comm drops. The TRIBO R/C Power Matrix Commutator Lubricant is the best stuff I have ever used. It works with <u>any</u> brush compound and is great for off-road too, since it has no petroleum products in it. It is 100% synthetic and doesn't attact dirt and dust nearly as badly as oily

products. And the TRIBO Power Matrix works great for bushings and bearings too. Go to their R/C web site for more info. www.triborc.com.



Now,I would suggest you lub your bushings or bearings,but sparingly.

Bung-drew
2011.09.30, 10:17 PM
Mine are atomic silver compound brushes,I have read about how certain comm drops could corrode the silver,sometimes lead to extra current draw...the extra current draw has happened to me several times already when my car goes much faster for no reason and I have to switch out the front tires to less grippy ones to prevent oversteer on throttle...

rock hard
2011.09.30, 10:30 PM
Even when comm drops are used,its supposed to be very,very miminal.
I wouldnt think a quality oil be corrosive,even to silver,though we learn something new every day.

I worry about the oil from my fingers as much as anything else,and typically wear non powder latex when handling comm and brushes.

I would think that maybe this "certain" comm oils quality is the problem.

I have yet to race these little guys,and cant speak from real world use in this hobby yet.

I know my 1st motor wil not get comm oil,I may however choose otherwise with gained experience.

Bung-drew
2011.09.30, 11:05 PM
i run the comm drops on the bushings. i dont like to use oil on the end bell due to it running down on the comm and causing more problems. as far as the comm drops on silver brushes i would not worry. they are not going to last long anyway.

Hm, so silver brushes wear out faster than carbon? How often do I have to replace them or are they any signs of them worn out?

blt456
2011.09.30, 11:26 PM
There is no set time when you replace brushes. The brush life depends on driving style, the motor itself (more rpm = extra wear), gear ratios, batteries etc...too many variables.

Generally, when your motor gets noticeably slower and lacks some punch that it had before, it would be a good idea to check the brushes. I would personally replace them when the bottom part of the brush arch is less than 2mm long (I break my motors in forward, which results in the brushes seating on the comm with an arch).

rock hard
2011.09.30, 11:34 PM
There is no set time when you replace brushes. The brush life depends on driving style, the motor itself (more rpm = extra wear), gear ratios, batteries etc...too many variables.

Generally, when your motor gets noticeably slower and lacks some punch that it had before, it would be a good idea to check the brushes. I would personally replace them when the bottom part of the brush arch is less than 2mm long (I break my motors in forward, which results in the brushes seating on the comm with an arch).


arc? like matching the curvature of the comm kind of arc?