03-11-2012, 12:49 PM | #1721 | |
Rock Crawler Join Date: Apr 2008 Location: Albany
Posts: 640
| Re: Cutting a motor commutator & motor tweaks Quote:
My luck and we would have been a Fire. Even if I had 100C rating on my 2 cell lipo. I have a carbon pile automotive battery tester. Its good for 500 amps at 12 volts. Now that sounds like a fun day in the back yard. Evan Last edited by SlickRockSpider; 03-11-2012 at 01:24 PM. | |
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03-11-2012, 12:55 PM | #1722 |
Nobody Join Date: Sep 2008 Location: Maine
Posts: 966
| Re: Cutting a motor commutator & motor tweaks |
03-11-2012, 01:16 PM | #1723 |
owner, Holmes Hobbies LLC Join Date: Nov 2004 Location: Volt up! Gear down!
Posts: 20,290
| Re: Cutting a motor commutator & motor tweaks
Just good batteries and less than a foot of 12ga wire. Now the real question is where the motor saturates and stops producing more torque, and starts being a space heater. |
03-11-2012, 07:49 PM | #1724 | |
I wanna be Dave Join Date: Nov 2010 Location: 07456 N. NJ USofA
Posts: 8,314
| Re: Cutting a motor commutator & motor tweaks Quote:
A clamping bar may be enough....it's a bit above my electrical knowledge.... | |
03-11-2012, 07:50 PM | #1725 |
I wanna be Dave Join Date: Nov 2010 Location: 07456 N. NJ USofA
Posts: 8,314
| Re: Cutting a motor commutator & motor tweaks Yep, power supplies have a hard time keeping up with a decent battery source.....since I work with large (30KVA-1400KVA) UPS systems....there is little to compare to a "shorted" battery!! |
03-22-2012, 07:40 PM | #1726 |
Rock Crawler Join Date: Jul 2010 Location: St. Albans
Posts: 507
| Re: Cutting a motor commutator & motor tweaks
What is the benefit of cutting the leading edge of a brush. I have heard of people doing it but have never seen it till I took a motor apart and saw it.
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03-22-2012, 07:44 PM | #1727 |
I wanna be Dave Join Date: Nov 2010 Location: 07456 N. NJ USofA
Posts: 8,314
| Re: Cutting a motor commutator & motor tweaks |
03-22-2012, 07:46 PM | #1728 |
Rock Crawler Join Date: Jul 2010 Location: St. Albans
Posts: 507
| Re: Cutting a motor commutator & motor tweaks
But this was done on a motor that you can change the timing.
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03-23-2012, 07:46 AM | #1729 |
owner, Holmes Hobbies LLC Join Date: Nov 2004 Location: Volt up! Gear down!
Posts: 20,290
| Re: Cutting a motor commutator & motor tweaks
It would reduce the commutation duration, making the motor a bit more efficient and have less power. If you had to choose between two motor winds and one was too fast and one was too slow, brush thinning is a good way to get the faster motor dialed down a bit.
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03-29-2012, 08:40 AM | #1730 |
Pebble Pounder Join Date: Sep 2010 Location: Lees Summit
Posts: 190
| Re: Cutting a motor commutator & motor tweaks
The best thread on RCC needed something to get it bumped back up, so I got my new (to me) Twister lathe going last night. I read this whole thread a few months back, and just started reading it again a few days ago You guys looked like you were having way too much fun in here, so I had to give it a shot. First arm cut was from an old twister a friend gave me in college. The next was out of an old Integy 55T I had here. Then I started working on a big comm Reedy that the seller threw in with the lathe. The twister lathe came in a plastic tackle box type carry case and came with some extra bits and shims and some thing that I don't know what it is. Its a nice little kit though. I am running it on 3.3V from a PC power supply right now, but based on the finish I am getting I wonder if I should try it at 5V instead. The first 2 comms cut looked great, then they started getting dull looking with lines on them. I am feeding it slow, probably at least 30 seconds per cut. I switched the bit that was on it for a new one (figuring maybe the bit was dull), and that didn't seem to change the finish. It is also possible that I have the bit on wrong, or something stupid like that, but I think I am good. Also, a couple of the bits it came with appear to be left cut, and I think I need right cut bits with this one. Can anyone confirm/deny? Last edited by schiesz; 03-29-2012 at 09:08 AM. |
03-29-2012, 09:14 AM | #1731 |
Rock Crawler Join Date: Mar 2011 Location: hampton
Posts: 984
| Re: Cutting a motor commutator & motor tweaks
i dont remember which direction my was running, but i got much cleaner cyts when i swapped the drive motor leads to run the other direction. i can look when i get home and let you know which way im spinning now. im running 5V from the PC power supply that feeds my chargers. i just added a 5V tap off one of the red wires, and the same ground as the 12v side |
03-29-2012, 10:08 AM | #1732 | |
I wanna be Dave Join Date: Nov 2010 Location: 07456 N. NJ USofA
Posts: 8,314
| Re: Cutting a motor commutator & motor tweaks Quote:
The lathe pictured wants the copper to be cut to come up from the bottom to the tool, NOT over the top to the tool. This helps "pull" the comm into the shaft rests rather than trying to pop it out. As to power, I use a charged 4 cell NiMH (~5 volts). | |
03-29-2012, 10:40 AM | #1733 |
I wanna be Dave Join Date: Jan 2008 Location: Arat Alabama
Posts: 2,678
| Re: Cutting a motor commutator & motor tweaks
I have a Twister lathe. It uses the AR(right) its and runs with normal polarity. You want the top of the arm turn away from you or the arm turning up toward the bit(same thing). 5 volt will most likely cut a bit smoother than the 3.3. You may have to shim the bit up or down. Most instructions I've seen say .001-.005 above the center of the arm. It is a good lathe you did not do bad in finding one Last edited by TEDROCKZ; 03-29-2012 at 10:45 AM. Reason: added a bit of info |
03-29-2012, 07:14 PM | #1734 |
Rock Crawler Join Date: Mar 2011 Location: hampton
Posts: 984
| Re: Cutting a motor commutator & motor tweaks
mine is turning clockwise (comm spinning up into the bit) it was wired counter clock wise when i got it and the arm was jumping around bad
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03-29-2012, 07:24 PM | #1735 |
I wanna be Dave Join Date: Jan 2008 Location: Arat Alabama
Posts: 2,678
| Re: Cutting a motor commutator & motor tweaks
Depending on the make and style of the lathe the motor wires different. Most AR type wire regular polarity and most AL type wire reversed polarity. Most common AR Twister Orion T4000 Trinity Fantoms Most common AL Hudy Team Orion Mod lathe Cobras The last lathe I bought(used AL style) come with a 27 turn fixed timed stocker that was wired reversed and it would get pretty warm. Last edited by TEDROCKZ; 03-29-2012 at 07:31 PM. |
03-29-2012, 08:03 PM | #1736 |
Rock Crawler Join Date: Mar 2011 Location: hampton
Posts: 984
| Re: Cutting a motor commutator & motor tweaks
CW/CCW determined by looking at the shaft spinning, or with the shaft facing away from you? mines the old nasty cobra off ebay a few pages back |
03-29-2012, 08:14 PM | #1737 |
I wanna be Dave Join Date: Jan 2008 Location: Arat Alabama
Posts: 2,678
| Re: Cutting a motor commutator & motor tweaks
I really don't use the CW/CCW wording. Just set the lathe like you are using it and the arm should be turning away from you looking at the top of the arm. The Cobra wires reversed -/+
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03-29-2012, 09:27 PM | #1738 |
Rock Crawler Join Date: Mar 2009 Location: Victoria BC
Posts: 988
| Re: Cutting a motor commutator & motor tweaks
been alot of reading in this thread, and im looking at getting a lathe, but there is sooo many choices.. can any one recomend me a complete ready to go out of the box lathe? every thing i seem to find you need to buy all the cutters etc seperatly :S links where i can order directly are always nice too! haha |
03-29-2012, 09:46 PM | #1739 | |
Pebble Pounder Join Date: Sep 2010 Location: Lees Summit
Posts: 190
| Re: Cutting a motor commutator & motor tweaks Quote:
For the tooling, as it has been stated many times in this thread, different lathes require different types... Mine uses AR tooling, but you can get either kind in carbide at McMaster for under $4. All these comm lathes use the 1/4" shank. | |
03-29-2012, 09:57 PM | #1740 | |
I wanna be Dave Join Date: Jan 2008 Location: Arat Alabama
Posts: 2,678
| Re: Cutting a motor commutator & motor tweaks
I guess your budget would be a factor. You want the best of the best Holmes Hobbies / Holmes Bikes :: Motors :: Brushed Replacement Parts and Service Tools :: Fantom Factory Commutator Lathe EddieO @Br00d had some really good one at one time to. The H.A.R.D. brand. No link Probably the best bang for the buck for new Motor Lathes & Parts for Slot Cars, RC Cars & Trucks R/C or RC - Team Integy Best of new and used and my favorite place. Good deals come through pretty regular lathe | eBay Quote:
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