Magic Box Motors

[pestobanana]

So I've been given a sample of these motors to test before they become available on the market. I will try to be objective with my review of these motors. They will be available in 30k, 35k, 40, and 45k variants. I chose to test the 30k and 45k, and I will be drawing comparisons with Tienly motors I have in my stash.



PRM... I hope they mean RPM lol.


Design Impressions:

The first thing I noticed with these motors is that they are likely made to compete with Tienly motors, which in my opinion are currently the best motors available on the market. They have the same can and end bell disassembly design as Tienly, and are available in the same variants. The armature shimming also seems to be good, at least on par with Tienly.

The end bell is metal, which to me is a huge bag of NOPE. Systema AEG motors were known to be some of the worst motors on the market since their end bells were metal and were poorly insulated, causing motor shorts. While I dislike the fact that the end bell here is metal, it seems to be well machined and well insulated. I have not had any issues, and when I tested with two probes, the only places that were non insulated were the threaded screw holes.

The brush hoods are much larger than standard AEG sizing, I beliee these motors use PTW sized brushes. I approve of this.


The shaft tower is the best fitting one I've ever seen, the Tienly one wobbles a bit. It has two sets of closed bearings inside, and seem to be made quite well. The pinion seems quite good, though I changed it out for the purposes of performance testing for reasons I will state later.

Performance:

Dry run:
Magic Box 30k - 2.8A
Tienly 30k - 3A
Magic Box 45k - 3.8A
Tienly 45k - 5.6A

The Magic Box motors draw less current than their Tienly counterparts, but they sounded like they were much slower.

I decided to test these motors an AR platform that I have. Since my setup runs Siegetek gears, and my Tienly motors have Siegetek pinions, I also put a Siegetek pinion on the Magic Box motors. Bevel required no height adjustments between motors.

Test Platform:
Siegetek 10:1 Gear Set (SS-3)
Modify Ceramic Bearings (on bevel and top of spur)
VFC Hardened Steel Bushings (on sector and under spur)
Modify M120 Spring
BTC Spectre (rewired using Mil-Spec wire)
Turnigy BOLT 2.8 Ah 3S 65-130C LiPo

Magic Box 30k:
Current Draw: 25A
RoF: 44 RPS

Tienly 30k:
Current Draw: 27A
RoF: 46 RPS

Magic Box 45k:
Current Draw: 32A
RoF: 51 RPS

Tienly 45k:
Current Draw: 45A
RoF: 60 RPS

It is abundantly clear that the RPM ratings on Tienly and Magic Box motors were taken under different circumstances, probably differing voltages. The Magic Box motors are slower than Tienly, but it does look like in the 30k series the Magic Box motor is 3% more efficient than the Tienly, and 20% more efficient in the 45k series. Since the 45k motors are so dissimilar in winding, I believe that comparison really has no merit, like comparing apples and oranges.

I suspect the difference in the 30k series would be due mostly to the motor brush sizing, while the difference in the 45k series is due mostly to decreasing marginal benefits in performance. If you don't know what that means, it means that as performance is higher, every increase in performance requires a disproportionately larger increase in input. I do not believe the 20% difference is due to the quality of the motors.

Internals and Design:

The Magic Box motor takes down exactly as the Tienly motors do, with four screws on the sides. The magnets seem good, fitment of the end bell is good despite my distaste in their material choice, and their brush sizing is a good improvement.

I have requested information such as wire guage, TPA count, and brush material, but I was denied. Tienly also is not willing to release that information.

I do however take issue with their commutator. It was definitely not rounded properly, as I saw uneven wear patterns consistent with what I would expect from an improperly turned commutator. I saw this issue with both of the Magic Box motors that I received for testing. The following picture was taken after just 300 test shots:



I did not want to wait for it to fail and I wanted to continue my testing, so I relathed the commutator and the motor still works to this day, probably 20k cycles later.

Another complaint that I have that really leads me to question the competence of the design team, is that the armature is of a ventilating design, yet the motor can has no ventilation holes... Tienly motors have ventilating armature, but they have ventilation holes to make use of that... Having a ventilating armature reduces performance by a small amount, so I really don't know why they would do that and then not make the accommodating modifications to the can to actually reap the benefits of having such a design... That's like putting your fan cooled laptop under some pillows so that the fan can NOT cool your computer and generate more heat while its at it.

Necessary Improvements:
-ventilation holes in motor can
-plastic end bell
-properly finished commutator

Conclusions:

This motor seems to have potential as a contender, and I hope Magic Box takes this feedback well and makes the appropriate modifications before the motors are released to the market. In the current state I may purchase one myself since I like the larger brushes and I am able to swap endbells if a short were to occur, however I would NOT with any good conscience recommend this motor to someone else given the issue with the commutator. I have a motor lathe so it doesn't matter much to me, but if you don't, the motor will quickly become useless.

I do like a lot of things. The tower fitment is great, the brush sizing is a huge improvement. The motor also seems to perform quite well in terms of input vs output efficiency. If the retail batch of these motors have the above mentioned changes then I would definitely see them being the top performance motor on the AEG market.

[Styrak]

Originally Posted by pestobanana

Another complaint that I have that really leads me to question the competence of the design team, is that the armature is of a ventilating design, yet the motor can has no ventilation holes... Tienly motors have ventilating armature, but they have ventilation holes to make use of that... Having a ventilating armature reduces performance by a small amount, so I really don't know why they would do that and then not make the accommodating modifications to the can to actual reap the benefits of having such a design... That's like putting your fan cooled laptop under some pillows so that the fan can NOT cool your computer and generate more heat while its at it.

Often times chinese companies copy designs without knowing anything about what shit does. This may be a reason for that.

[EOD Steve]

If these are test units and you got them for free - why not cut them open and count the turns and also measure the wire gauge?

So in conclusion, Magic Box still doesn't make any quality products yet. I would be interested if they take the advice put forth and look forward to seeing the final Production units reviewed again.

[BioRage]

Originally Posted by EOD Steve

If these are test units and you got them for free - why not cut them open and count the turns and also measure the wire gauge?

So in conclusion, Magic Box still doesn't make any quality products yet.

Don't think you expected much anyways.

:P

[pestobanana]

Originally Posted by EOD Steve

If these are test units and you got them for free - why not cut them open and count the turns and also measure the wire gauge?

So in conclusion, Magic Box still doesn't make any quality products yet. I would be interested if they take the advice put forth and look forward to seeing the final Production units reviewed again.

I don't want to tear the windings apart yet, I'm more interested in seeing if the motor will fail in any other way in the long term. I'm especially interested in seeing if the metal end bell will cause a short in the long term.

I am hoping that Magic Box will take my feedback before releasing the actual production batches. I see very good potential if they do. Lonex had several batches with literally the worst commutators I've ever seen, but they've gotten their shit together as far as the commutator went.

If they don't, I expect it to be another big hit to their reputation. People will be buying a $90 motor and having the comm deteriorate and fail very quickly.

[pestobanana]

I have now just realised that the motor brushes were not installed correctly on these motors. Thanks Magic Box, please fix these issues before you distribute your motors to retail channels.