Cutting a motor commutator & motor tweaks

[JohnRobHolmes]

Originally Posted by EddieO

JCboof, sure likes the skews you sent him. I have not seen a single other of your team drivers post they were using skews.

Not all of my drivers post up every single thing they try. Like I said before, choices are good to have even when some are not so ideal. Diffrent strokes for diffrent folks.

Our weather? You realize in washington, it doesn't rain all the time like everyone thinks right? 38+ states every year have more inches of rain fall per year than washington does, including you own state. Our average humidity is low 80s, as is yours....same as Michigan where Fantom is. My trinity arms always had LESS rust than Sagami stuff, and their humidity in NJ was the same (now Florida). Arms straight from Reedy in sunny california used to arrive with rust all the time, same with Checkpoint and Orion.

Add in the fact, my shop is in my house (not the garage)....where there is no humidity really....

I was just wondering if it was a weather thing, thanks for the quick synopsis on how the states compare though

If you look closely at your arm, its either REALLY dirty between the laminations or those are small things of rust. What's the black residue on the top of the segments?

Thanks for picking apart my photo? Some sort of positive feedback or support would be cool considering winders are a dying breed, but... I wasn't aware I was posting up perfectly done armatures I'm just proud to build something that people can use and enjoy, I've only been winding a few years professionally so it is still pretty cool to build a motor from start to finish with my own hands.

Is there a reason you typed out my full name? Not that I care, just seems strange...

Later EddieO

I type what I think, didn't even realize. I can take it out if you want.

[EddieO]

Seems odd since many of your top team guys have build threads with detailed information on changes they make to the rigs.

I guess ideal is in the mind of the beholder...

After 36 years of listening to "it rains a lot there" it gets old, so many learn the stats.
My photo got picked apart...I simply asked what the stuff was on yours....

But to comment on the rest arm...winding looks good, solder job looks solid...epoxy looks applied uniformly...comm cut looks spiffy



Later EddieO

Originally Posted by JohnRobHolmes

Not all of my drivers post up every single thing they try. Like I said before, choices are good to have even when some are not so ideal. Diffrent strokes for diffrent folks.



I was just wondering if it was a weather thing, thanks for the quick synopsis on how the states compare though



Thanks for picking apart my photo? Some sort of positive feedback or support would be cool considering winders are a dying breed, but... I wasn't aware I was posting up perfectly done armatures I'm just proud to build something that people can use and enjoy, I've only been winding a few years professionally so it is still pretty cool to build a motor from start to finish with my own hands.



I type what I think, didn't even realize. I can take it out if you want.

[Duuuuuuuude]

Originally Posted by EddieO

My photo got picked apart...

I don't think he did that...I was wondering about that stuff too, but didn't care enough to ask because I was relatively sure that it all gets cleaned up in the build process. A lot of things can look a bit funky early on in the manufacturing...

[TEDROCKZ]

More Ebay findings
Found a good deal on a Cobra Motor Builders lathe. It is a bit different than the cheaper cobras. Better carriage and has billows to keep shaving out of the workings. Plus it has a power base for it's own battery source. Came with 3(2 new in pac) diamond bits. Not bad for A $100.




Funny thing after I bought it was I could not really find any loose cell NIMH batteries. PMed Eddie and asked him and he said he had a "few". Got a package in the mail today.......Let's say I have more than enough now

[EeePee]

Originally Posted by TEDROCKZ

and has billows to keep shaving out of the workings.

Weird. That's got to be home made, yeah? I mean, I've never seen that before.

Edit: Interesting, with the four set screws to locate the bit.

[TEDROCKZ]

Originally Posted by EeePee

Weird. That's got to be home made, yeah? I mean, I've never seen that before.

It's on there site! Search newb

Team Cobra Com Lathes

Towards the bottom.

[Duuuuuuuude]

Now that's fancy!

[TEDROCKZ]

Also was sort of a throw back day as well. Been several years since I've actually built a battery pack. Flashbacks!!!

[EeePee]

Whatever.

[Knarly Nerd]

I'm glad there was nothing on my calender today. I spent half of it reading this thread. Nice job, fellas!

[JohnRobHolmes]

Those little chip guards are pretty cool! You have been on a mission for tools tedrockz!

[TEDROCKZ]

Sorta! On a mission to find a new Orion motor checker. Done the most worst absolute dumbest thing you can do with one to mine. Hooked both leads to the same side of the motor. Was bout half assed tired and was not paying attention. It let out the magic smoke and I could not gather it back up.

Probably settle for the Muchmore unit instead. Pulled the Orion apart and it has Muchmore printed on the board.

Originally Posted by JohnRobHolmes

You have been on a mission for tools tedrockz!

[JohnRobHolmes]

Did you fry the traces, or just the FETs? I would wager it was just the high side FET that let out the magic.

[Duuuuuuuude]

Why don't they put fuses in there for that? You would think it would be a no-brainer...

[JohnRobHolmes]

A fuse wouldn't catch it quick enough before the FET goes, unless the FET is way over rated. In that case the next weakest link goes, which is normally a pcb trace. The only real solution is pulse by pulse current monitoring with a high enough impedence in the system to help clamp the current before things melt down. None of the old brushed motor tools had current limiting, they are all simple pulse width modulators with no feedback circuits.

[jcboof]

Originally Posted by EddieO

JCboof, sure likes the skews you sent him. I have not seen a single other of your team drivers post they were using skews.

Yup, Sure loving my Skewed arms! Very smooth startup and very snappy top end. I actually ran a dirt oval race for fun with my crawler about a month ago and my 35T Skewed Holmes motors took the crown out of 8 other drivers running their 35T handwounds. Heck, I actually got two laps on a few guys!
I should put a wing on my truck for more downforce.

Originally Posted by JohnRobHolmes

It is the difference between needing a 650mah pack and a 1000mah pack for a course,

I actually get really good run times out of my packs. During practice, I can easily get 15-20 mins out of my 850mah packs.

Most of my average 8 gate courses take about 150-175mah out of my packs.
Only thing I've noticed though, is that my 40C packs don't have quite enough grunt at times. It seems that the motors draw more current under Heavy low RPM loads possibly causing my batteries to amp out.

Any ideas what kind of amps these motors are capable of drawing?? Maybe I need a higher C pack to get through binds.

[JohnRobHolmes]

You do get really good runtimes on them compared to the other feedback I've gotten! It is in a 2.2 though, and I was thinking supers on the battery. You're probably one of those smooth drivers that doesn't grunt through everything ;) A 35t can burst over 100 amps pretty fast in a stalled condition, measured in the vehicle. Heck, I've even bench measured over 500 amps on a stalled 55t motor on 7 volts. So it just really depends on how deep you bury the throttle, the battery resistance, and how slow the motor is spinning. Bottom line is that you will need more battery power than a regular 35t or similar CrawlMaster because of the efficiency loss.

Even though I'm not so fond of the skewed arms, I still brought another batch in with the last Sagami shipment. It's not like my opinions are THE answer. I just like pushing towards efficiency of design whenever possible.

[jcboof]

Originally Posted by JohnRobHolmes

You do get really good runtimes on them compared to the other feedback I've gotten! It is in a 2.2 though, and I was thinking supers on the battery. You're probably one of those smooth drivers that doesn't grunt through everything ;) A 35t can burst over 100 amps pretty fast in a stalled condition, measured in the vehicle. Heck, I've even bench measured over 500 amps on a stalled 55t motor on 7 volts. So it just really depends on how deep you bury the throttle, the battery resistance, and how slow the motor is spinning. Bottom line is that you will need more battery power than a regular 35t or similar CrawlMaster because of the efficiency loss.

Even though I'm not so fond of the skewed arms, I still brought another batch in with the last Sagami shipment. It's not like my opinions are THE answer. I just like pushing towards efficiency of design whenever possible.

WOW!! I had no clue that they could draw that type of amperage.
I guess with battery that only puts out 34 amps, its definitely amping out the packs.
Damn, what to do now..... Really don't want to go back to 1000mah packs.... Maybe the Thunderpower 65C packs would be better.

[Cordwood]

Originally Posted by JohnRobHolmes

Heck, I've even bench measured over 500 amps on a stalled 55t motor on 7 volts.

Holy sh*t that's some serious amps for a little 540. That 55t must of been screaming for mercy. What 7 volt battery did you use that let it draw 500 amps?

[JohnRobHolmes]

That was with a matched sub-c pack. A modern 5000mah 2 cell lipo is even lower resistance. You bet the motor was screaming for mercy! So was the amp meter Nothing got damaged but there was a bit of smoke.


You could also try shortening your wires or stepping up wire diameters to reduce the voltage drop. Every little bit helps, even if the battery is taking a beating.