Tuesday, July 7, 2015

The Situation With "Meishel" Motors

When I did my electric pistol build, I decided on these 4666kv generic FK130 motors that redditor /u/Meishel found on ebay a while back. However, what arrived in the mail was not in fact the same motor.

It turns out there has been a substitution across multiple sellers, perhaps at the supplier level, of a vaguely similar motor and I was one of the first to receive the new ones. At the time, I was oblivious to the difference, because I hadn't used the original Meishel motor. It wasn't until I put the thing together that I noticed anything remotely amiss (the high speed and noise of these things compared to what I was expecting them to do), and then after redditing my blog post, Meishel commented. Further research blew the can of worms wide open. So here's the deal.

This is a true "Meishel" FK130 motor. Note the SQUARE vent hole in the can, the standard zincplate finish on the can, and the standard length FK-series shaft end which is exactly like the one on the Mabuchi FK180SH-3240 and other Mabuchi FK motors you may have seen.



Proper specs for torque and current draw are maddeningly nonexistent on these, but what we know is "28000rpm @ 6.0V" which gives a kv of 4666.

These motors are well tested with 2S lipo batteries. They turn at ~34500rpm unloaded giving nominal performance, and have response and torque noticeably inferior to the Falcon WFK130SZ-2190, but pretty damn good for a 130 motor, especially for one that uses a simpler and more space efficient 2 cell battery and is thus well suited to pistols where fitting in a 3S pack with enough guts for Falcons would be difficult.

Now this motor is the new one people are getting from former Meishel listings which is NOT a Meishel motor. Note rectangular vent hole, longer shaft (only a good feature for flywheels) and can that appears hot galvanized or plated with heavier zinc.





(right)


This motor is rated at 25000rpm @ 4.8V, giving a kv of 5208. It is wound substantially hotter than a "Meishel".

On 2S lipo, this motor turns at circa 38000 rpm. This is not an optimal setup, speeds over ~35K are not helping with velocity and might decrease accuracy and consistency. Plus the obvious noise. Durability and reliability are not well known for this combo but I don't expect trouble out of these from how mine have acted so far.

Some comments about reliability concerns, brush gear, LiFePO4 batteries, and such for this 5200kv FK130 "banshee" motor in this reddit thread.

12 comments:

  1. Toruk I was wondering where you get your Xtreme Pro 180s and FK180SH-3240 motors because I recently bought a set of three FK180SH-17140 and didn't realize that 17140 were bad until today. So if you could help thanks and if its too much too ask, no big deal.

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    1. Your best best for real mabuchi -3240 right now are the RC rebadges as stock motors for various helis and stuff. Eflite/Blade, E_sky, Losi, etc. Same with XP180, that is a RC market product in itself.

      A group I am working with is likely to resell the real Mabuchi -3240 at competitive cost in the future.

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  2. Toruk are these real FK180SH-3240's or no?
    http://www.ebay.com/itm/3-x-Nichibo-Motor-FK-180SH-3240-3V-DC-12-900-RPM-RC-Hobby-Shaver-Printer-Train/121624679840?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D32474%26meid%3Df2fb5adbf69e4b31b393e090f340b0ee%26pid%3D100005%26rk%3D4%26rkt%3D6%26sd%3D121624679693&rt=nc

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    1. That's a Nichibo FK180SH-3240 that Zinky was able to get in stock. Hasn't been tested yet, but it is not a Mabuchi motor.

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  3. I bought 8 of these. So far I only shot 5 darts indoors (3ft height with 1in upward tilt) and got 64ft with 7.2v. I'll keep posting the more I test.

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    1. Nichibo Motor 1

      7.4v
      Avg RPM 25740
      Max RPM 25860
      Current .41 amps

      3v
      Avg RPM 12500
      Max RPM 12720
      Current .25 amps

      (Mini-Z RPM app)

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  4. Found that the "reversed polarity" motors fail after an hour of average use. They had a lot of shaft play after inspection and the bearing was opened. Not sure if I had a bad batch or if they're just not durable like Mabuchi. How much maintenance is there with 180 motor upgrade (i.e. relube the bearing after every use, etc.)? I have two more sets to test on but any input would help.

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    1. What motor is this, the Nichibo 3240?

      Do you have more than one motor failure on reverse rotation to correlate the failure to the aforementioned or is this just a single random bearing failure? Reverse rotation should not affect them, they are not directional.

      Maintenance on normal 180 setups is nonexistent. These bearings are a sintered bronze insert containing oil and are considered lifetime lubricated, although it doesn't hurt to oil them on occasion. If a new one wore out that fast it is a defect.

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    2. yes I am testing Nichibo 3240s. Out of the 4 motors, 3 were reversed polarity, the fourth was dead from handling (I was a bit too rough on the pole so it broke contact internally). One thing I do note is that I did not have any rc oil, all I had at work was Tri-Flow Industrial Lubricant that I used to relubricate the bearing after I did a dry break-in. I won't be surprised if that caused the failure. I do have one more set to test that are untouched if you have any suggestions for a more controlled test.

      Also, would you like to make a dedicated section for the Nichibo 3240 and I can post results there so we are not mixing information?

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    3. Ya, I bought the Nichibo and they burned themselves out after 3 hours of use on 2S 2200mah 40C lipo

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  5. Opened both failed motors and the brushes are just flat and thin metal rakes that sit on opposing sides of the commutator and point in the direction of normal rotation. The reversed motor just ate through one brushes hence why it failed to keep connection. Nichibo is NOT a suitable substitute.

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    Replies
    1. Thanks for the heads up, I will put up a PSA post.

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