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Tuning motors with brushes

Tuning motors with brushes

Old 03-23-2004, 07:59 PM
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Default Tuning motors with brushes

hey,
just wondering what there is u can do to brushes to make motors perform..... different and hopefully better???

ive heard ppl do stuff like slotting and trimming and filing the trailing edges..... what does all this do??

could somebody please point out what each different thing does and if not too much trouble, any reccomendations?
i run stock

thanx
robbie
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Old 03-23-2004, 08:01 PM
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I like to run a polarized brush setup. Ie: Putman Green/Red. And a harder spring on the Pos+ side. And trim 1mm of the trailing edge.
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Old 03-23-2004, 08:02 PM
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what does stuff like that do though??? like does it increase torque or rpm or anything?
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Old 03-23-2004, 08:02 PM
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I personally just get the reedy 767, 766 brushes. There supposed to be great. After awhile of you cutting your brushes they end up wearing down to nothing. I usally just cutt the comm, install new brushes and get some good springs (red,green(i think, may have been purple) And Viola brand new, or even faster.
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Old 03-23-2004, 08:12 PM
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Trinty purple on stock? Your comm must wear fast. . ..
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Old 03-24-2004, 01:43 PM
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The theory is that the power goes in through the posative side and out the negative side. Thus, you put a high silver content brush on the posative side to increase and or provide solid current into the motor and a low silver content bursh on the negative side so that is can aid in lubrication and allow the current to leave under realitive ease. Following this theory, you put a stiffer spring on the posative side to "force" the current onto the comm while giving the motor more torque. Then put a not as stiff spring on the negative side so there is very little resistance for the current to leave through. NOTE: the differencce in spring tension should be no more than one rate. Generally, I like to run Blue on negative and Red on posative.
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Old 03-24-2004, 01:49 PM
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Acctually you have it backwards. Current flows from negative to positive. But your are correct on the polerization of the brushes. The reason you use a higher silver/stiffer spring on the positive side is because the current is flowing INTO that brush. Therefore the current wants to PUSH that brush away from the comm. On the negative side of the motor, you don't need as high of silver and want more lubricity because the current is pulling that brush into the comm.
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Old 03-24-2004, 03:44 PM
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ummm... i think your wrong and he is right, is this polarity? it flows from postive to negative, doesnt everything go from postive to negative? And i believe you use heavy springs on pos. and softer on the negative.
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Old 03-24-2004, 04:03 PM
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NO. Electricity FLOWS FROM negative TO positive. You fall asleep in science class?

And he is correct about the spring tension, but he had the wrong description of why it is that way.

You ever hear about how they plate parts with say...cadnium? They hook the anode to the part (thats positive) and they use the cathode to apply the material (cathode is negative) The electricity flows from negative to positive, carrying with it particles of cadnium, adhereing them to the part.

Same with the brushes. If the brushes didn't wear out due to friction, the brush on the positive terminal would eventually be covered with copper because the electricity is pulling the material from the comm, trying to deposit it onto the positive brush.

Please, ask anybody that acctually knows something about electricity. negative to positive.
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Old 03-24-2004, 04:27 PM
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He's right...somewhat reverse logic until you examine it in depth, but electricity does flow from neg to pos...
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Old 03-24-2004, 04:47 PM
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Oops, my bad. Must make a correction to my previous statement. In eletro plating, the part being coated is negatively charged, and the salt solution of the metal being deposited on the part is positively charged. The positively charge particles are attracted to the negatively charged part being coated, however (and this is important) The electrons flow from the negatively charged part being coated, reducing the salt form of the metal, reducing it to metal form and depositing it on the part.
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Old 03-24-2004, 08:42 PM
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ok, thanx for that guys.........

one more tho.... can any one help me with stuff like slotting, chamfering and trailing edge and so on? what does it all do??

thanx
robbie
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Old 03-24-2004, 09:43 PM
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Horizontal Slot: decrease current draw, increase cooling and efficiency, slight loss of power.

Hole: Can run softer spring and still have the same effect of a stiff spring, increased cooling and increased power.

Vertical Slot: Increase efficiency but a ton of power loss...rarely used.

Half Cut: Brushes are cut in half from top to bottom. Run the bottom brush on the posative side and top brush on the negative side. Drastically increases efficienty, reduced surface area, softer spring used and slight loss of power. Great for mod or endourance style applications.

Chamfer Edges: File the edges (sides) of the face of the brush at a 45 ish degree angle on both sides of the brush. Less surface area and less current draw because the edges were shaved away. Half way through the race, the brush will wear itself back into a full face form and your batteries will last longer....more punchier feel for a longer time.
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Old 03-24-2004, 09:51 PM
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so would it be good to chamfer the brushes on both sides for stock racing?>

or only on one or the other? or just use standar brushes
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Old 03-24-2004, 11:16 PM
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I tried chamfering both sides with my monster stock and didnt like it at all it felt flat. If anything do the trailing edge of both brushes at a 45' 1mm wide. Each motor is a little different on what it likes as far as tunning.
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