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Posted by --Oz-- | Mar 15, 2019 @ 11:15 AM | 3,531 Views
1,000,000 RPM and Explosion @ 688mph (0 min 48 sec)


This thread is for high rpm motor discussion of the electrical type.
Post videos/schematics/how-to/info/questions/etc.
Post results, ideas, comments, questions.

After playing around for a few weeks I cracked 1Mrpm two years ago, then I put it in a box. A recent YT video urged me to get my project off the shelf and make a video.

In this video I am seeing how fast a ball magnet will go. My top speed sofar is 1,140,901rpm, 19.02KHz (revolutions per second), maximum 5mm ball equator speed = 668mph (979kph). Pretty much every 5mm ball magnet explodes at 1.1 million rpm sofar.

I used a brushless fan hall sensor controller AH277A, I did not choose that p/n, its just what I found, I just got it out of a brushless dc fan of 40mm in size. It has two open collector outputs that drive the coils, I am currently only using one, the other I was going to use for a push/pull coil circuit. Since I wanted more current, I drive a larger FET and simple coil. To clean up the main N-FET gate drive, I am pre driving the main FET with a P-FET. This is not ideal like a dedicated gate driver would be, but it works.

I have quite a few ideas to go faster (better drive electronics/focused flux path/push-pull/air bearing/vacuum/etc), but right now the limit is the 5mm self exploding balls. So I just ordered some 3mm balls from china.

Anyone know how to calculate centrifugal acceleration and force? (weight is 0.5g)

WARNING: Wear eye protection as a minimum if you try this, have fun.

Seems this is the worlds fastest 60 billion revolutions per minute
Posted by --Oz-- | Feb 13, 2019 @ 10:40 PM | 4,234 Views
I bought the M9-R on sale for $34 a pair 6 months ago, I just couldn't pass them up. Even though I did self modded hall gimbals in Jul 2016 and still work perfect, around 20K flights on them.

I wanted to use the short throw on the thro and modify the other gimbal back to normal 60 degree throw, also they will match color. After collecting dust for 6 months, in a couple of minutes looking at it, bingo, simply add four 1.5mm washers under the red ALU plate (see picture), now it has the stock ~60 degree travel like the stock gimbal has.

I took some OTX raw data and photos to compare travel degrees of all four axis. Looks like the raw travel numbers are within reason of the other axis (AIL and YAW) movements (+/-~100). These numbers have a lot to do with how close the sensor is to the magnet (closer gives larger range).

I took some pictures to compare my 1.5mm washer mod to see how close it is to 60 degrees. Roughly its ~1.5 degrees less than the other two axis (AIL & YAW). Of course there is some error in my measurements. I am pretty happy with a first try with 1.5mm thick washer guess.

I did the heat shrink tubing over the thro drag bar and a dab of rc car diff grease, this thro gimbal now feel as smooth as anything I have felt. So far pretty happy with them.