The first in the line of new light-weight motors from ZMX.
Check out the full list of motors in this series here
Summary
Published: Nov 8, 2017 by quadmcfly
| Tested KV: | 2620kv |
| Weight: | 24.6g |
| Stator W: | 22mm |
| Stator H: | 5mm |
ZMX has a long history in this hobby, helping create some of the defining motors of the FPV racing and freestyle world. With the FinX series, ZMX is looking to again change the industries expectations, this time with power to weight expectations. The most significant element in the design of the FinX motors is the "fins" that create a ripple in the bell. Those fins go beyond decrative and perform a critical function in the design of the motors, redirecting lost magnetic field strength from outside the bell back towards the stators. Theoretically this allows smaller and lighter magnets to be used with equivalent effect, producing a much lighter motor with equivalent power. The reduced loss of the magnetic field is readily evident, as the bell can barely pick up small steel scews and the attraction to other nearby motor bells is dramatically reduced. This is probably one of the only real attempts at innovation that I've seen in motor design in the last year or so, so it's exciting to see. Due to the light weight design, this motor comes in at only 24.6g with 40mm of wire. In addition to the light weight design, these motors keep much of the recent design trends, both in weight reduction and performance. A hardened steel shaft, hollow 5mm external and solid 3mm internal with a 12.9 steel retaining screw are combined with 0.15mm laminations, an ultra-tight air gap, and magnets that overlap the stators above and below, giving a bit of extra field strength and less loss at the stators. The hardened steel is critical over a titanium alloy due the smaller 3mm internal shaft, as hardened steel is significantly tougher than its titanium counterpart. All of these factors make this a very fascinating offering in the ultra-light market.
Result
The numbers here don't seem all that impressive until you take the weight of this motor into account. At under 24g with short wires, that puts this motor into the ultra-light category. Given that constraint, these results are quite impressive. The fins don't appear to completely make up for the thinner and lighter magnets, but they are definitely doing their part. The cost here seems to be efficiency, showing a few amps higher draw than typical across the range of results. Given the target application though, this is not likely to be a significant issue, as weight plays a significant role in unloaded efficiency, and ultra-light builds will unload much more dramatically than their heavier counterparts. The current rise is fairly typical when you see a lower torque motor driven to higher power output. The thicker single wire windings are likely to handle the current and heat load well with minimal losses as well. It is interesting to note that this motor essentially matches the output of the early generation 2206 2600kv design, but at nearly 4grams less weight per motor. Overall this is a very interesting motor, and I will be curious to see further developments along this front.
