Electro&Co EC4P

[Barncat]

Any users out there who've put some hard miles on this motor? Considering buying one soon... at 300 bucks shipped it looks to be a pretty fair deal. They've done a nice YouTube video ad/teardown.

Given the 100% reliability and good performance/value of the (3) 3000W MY1020's I have, this would be an upgrade- and very easy to program in vesc-tool for the Flipsky 75200 on hand. Claimed 14kw bursts. Should run even smoother with 4 pole pairs instead of 3. Significantly larger diameter higher torque rotor. Thinner laminations. Claimed high temp windings and magnets with upgraded hall sensors. Shell is all fins and would run cooler. I'd probably still drill the end caps for street use as I don't ride in rain. Very high voltage rating at claimed 30s- I'd use 20s. Probably weighs 11ish lbs, which is better than the 17-20lbs of the next tier mid motors, and 200 bucks less.

 

[fechter]

Do you have a link for this?

 

[A-DamW]

Do you have a link for this?

Fairly sure it is this one:
https://www.electroandcompany.com/product-page/ec4p-brushless-motor

 

[Barncat]

Yes that's the one. Thanks A-damW.

My guess is it's made by the same factory that does the MY1020's. Based on the specs, I'm pretty sure I can get 60mph out of one with gearing and a 20s5p p42a pack.

 

[DogDipstick]

Yes that's the one. Thanks A-damW.

My guess is it's made by the same factory that does the MY1020's. Based on the specs, I'm pretty sure I can get 60mph out of one with gearing and a 20s5p p42a pack.

What " specs"? The claimed contin power of the ( that) motor?
The Ir of a 5p of a 20A cell? a 40mOh pack ?
60mph?

idk about that. would love to se it happen tho. Lol @ the " 14kW peak " number without a " contin": number. Last week they were at " 11kW peak max burst"..



So good luck. IDK about 60mph. Good luck tho.

 

[Barncat]

DogDipstick- your commentary is unclear. And please see sentence one of my original post. And the Molicel 21700 P42A is a 45A cell.

I now have some experience in these matters, and a brief 60mph peak running downwind on the flat is a reasonable target if the EC4P operates in the ballpark of their advertised specs without blowing a magnet- which would be my main concern.

 

[amberwolf]

Is it IPM or SPM? If it's IPM, it shouldn't have any problmes with the magnets coming off the rotor.

SPM, well, that depends on the glue used to secure them. IIRC there were some experiments with Zero 75-series motors to use Kevlar wraps on the rotor to help with that; I dont' recall the results.

 

[Barncat]

It's SPM, and according to their YouTube video, the rotor is Kevlar wrapped. Which is all fine if it works. The MY motors use thin steel bands to retain the magnets- Kevlar is of course a higher tech approach.

Anyone interested can easily find the video to examine the internals. To my eye the segmented magnets in their example have axially shifted by .032 or so, which is not ideal.

If anyone on site has actually used one let me know...

 

[amberwolf]

If the magnets can shift (even ty tiny amounts), I'd say that they aren't glued down correctly (or not sufficiently, anyway) for the motor's intended usage / specified capabilities. Might just be me....

 

[Barncat]

Update: I have over 1000 miles on my Hyper 29er build sporting the black EC4P motor in pics below. It has performed great, runs cool, and pulls hard all the way to 60mph on a 20s battery with a Flipsky 75200 controller.

I just received the silver motor that I'll be installing on my Mongoose Blackcomb build from a couple years ago, also with a new 20s pack and 75200. Gave up on the original T-Motor U15, too difficult to control. It's on ebay as we speak...

 

[etass]

BARNCAT COULD YOU GIVE ME HOLE SPACING sorry and motor depth pleaaaase? i ordered my motor but want to start making mounts. or do you have a cad file? thank you very much

 

[Barncat]

PM sent a week ago. Good luck with your project.

These motors are serious bang for the buck. The new silver one had defective Hall sensors right out of the box, but runs great sensorless anyway. They have very high cogging torque and must be run with a freewheel- or even better my new custom sprag bearing sprockets. The first 10% of their rpm range is a little electrically noisy but they really fly above that especially on 20s/ 84V.

 

[Barncat]

This disassembled motor may be of interest to some.

2 days ago I noticed some .100 inch of axial end play in the shaft, which didn't seem kosher... I thought a bearing or some locating interface had failed somehow. One simply removes the 4 long screws that secure the end caps, then use a long thin punch to easily tap the caps loose, then loop a bit of rope around the sprocket and pull the rotor out from that end.

It's a pretty decent looking unit, high copper fill with the segmented construction, they used thin laminations, fairly tidy on the terminations end, lots of fin heat sink of course. No evidence of scraping on rotor or stator.

The odd issue is the wave washer they used on the sprocket cap end, which allows the aforementioned axial play. How can that be good?

There's a 6201 bearing on one end and a larger 6003 on the sprocket end. Neither are press fit into their respective housings, and it appears that the bearings are at least intermittently spinning in same as opposed to being stationary with just the shaft free to move.

I'm going to toss the wave washer and turn a custom shim washer that'll properly lock the stack in place when assembled without excessively preloading the bearings.

 

[amberwolf]

The odd issue is the wave washer they used on the sprocket cap end, which allows the aforementioned axial play. How can that be good?

I don't know why they use them, but most motors I've had to open up do this, from tiny little drill / etc motors, to nearly all the hubmotors I've opened. Even some of the bigger brushed motors from powerchairs and the like. Some of the springy wavelike washers appear to be a strong enough form of spring steel, but most of them are too flimsy to do the work they are there for.

I'd guess that the machining of the casings, shaft or axle shoulders, and all the other things have so much slop tolerance in the processses that they can't guarantee a sufficiently small total amount to just stick a specific spacer washer in there, and won't pay to spend the time swapping washers or stacking thin ones to give a good enough fit, so they use a springy washer....

 

[Barncat]

Very astute observations as usual amberwolf. It's a not-great manufacturer shortcut. I suppose a stronger wave washer would be an improvement, but I'm going to try the hard way with a fixed shim washer. The tough part is getting a shim thickness measurement for the assembly within .002-.003", though I have a plan. I don't like the idea of the bearings spinning in the end caps.

 

[DanGT86]

I don't know why they use them, but most motors I've had to open up do this, from tiny little drill / etc motors, to nearly all the hubmotors I've opened. Even some of the bigger brushed motors from powerchairs and the like. Some of the springy wavelike washers appear to be a strong enough form of spring steel, but most of them are too flimsy to do the work they are there for.

I'd guess that the machining of the casings, shaft or axle shoulders, and all the other things have so much slop tolerance in the processses that they can't guarantee a sufficiently small total amount to just stick a specific spacer washer in there, and won't pay to spend the time swapping washers or stacking thin ones to give a good enough fit, so they use a springy washer....

My theory of why so many motors have wavy washers is to prevent axial bearing loading due to thermal expansion. The expansion along a shaft can be significant compared to the diameter expansion we normally think about when assembling and press fitting stuff.

I always just guessed they didnt want bearings trapped.

But its probably more likely because assembly with sloppy tolerances is cheaper.

 

[lnanek]

I'm a software engineer, but I watched a half hour video on washers the other day:

Did convince me that sometimes the choice of wavy ones is intentional to produce a spring force. Sort of like how springs are used in the ends of quick release axles to keep them centered.

Personally I tossed out all my split ring washers and loctite covered bolts and replaced them with nord-lock a long time ago, so totally understand wanting to eliminate a wavy washer somewhere, though.

 

[Barncat]

This topic is more interesting than I'd initially assessed. Accurately securing two bearings on a shaft in fixed housings/end caps in an assembly that can see over 100*F temperature swings and also must be occasionally disassembled presents problems. There must already be solutions to this in more expensive equipment, but I'm giving this some design attention.

The givens are that the supplied wave washer is too weak, and spinning outer bearing races is pretty much unacceptable to me. And conceivably during every accel/deccel the rotor is hunting for a stable L/R location, which is transmitted through the chain. Inefficiency, noise, wear, heat, etc...

DanGT86- you raise a good point that I'd considered re tolerances and thermal expansion. Using the formula ^L= aL^T for carbon steel, where the expansion coefficient is .000001, the length between inside bearing faces is 4", and the temperature swing is about 90*F, the total axial expansion of the shaft is a mere .00036", or not quite four ten thousandths. These ABEC 1 deep groove bearings should be able to handle that if I don't preload them excessively. Plus it's not really clear whether the two aluminum end caps will expand inward or outward at operating temperature, my guess is the latter.

Inanek- I wasn't even familiar with nord-lock washers, so thanks for that. I use nylon insert nuts wherever applicable.

I'll probably work on a modification this afternoon or tomorrow...

 

[Evwan]

@Barncat , I'm looking at picking up one of the silver EC4P lite motors for a razor build. I'm not going to be doing anything crazy - MakerX G300 VESC and an 18s pack, mostly doing light cruising on trails. Electro and Co says 300 motor/150 battery amps, but that seems a little ambitious, and this video

has me a little worried (I understand this is effectively 2 revisions behind, but some of his complaints still seem valid). Would you recommend it?

 

[Barncat]

Evwan- the producer of that video, who is now I've heard deceased, was knowledgeable but known for being highly opinionated. My experience with both of those motor types has been very good. I run (3) 3000W MY1020's at 80A, and (2) EC4P's at 150A/260+A, all on 20s. Entirely street use, never in rain, never more than 20 seconds intermittent WOT. The red and silver bikes below can hit 60mph.

The silver motor above had dead Hall sensors right out of the box but runs fine sensorless. Electro & Co is improving the EC4P each iteration with their Chinese supplier, and AFAIK it's the best commonly available unit around for under $250 for chain drive builds.

The alternative is trying to order another brand direct from TopPower, which I've never tried...

 

[Evwan]

Oh wow, that's hard to hear. He comes across as super knowledgeable, it a shame we lose someone like that.

I totally get the strong opinions. In the world of esk8 battery building, we're really stringent with our standards due to all of the vibrations and movement caused by our flexible battery enclosures and tiny, hard wheels. Admittedly, we've crucified people for less.

Thank you for your response. I'll probably end up picking one up as I'm not trying to break the bank for this build. It originally started off as a "spare parts" build with leftover esk8 stuff and a $60 facebook marketplace bike, but then I realized the stock suspension and single esk8 motor would be inadequate, and it all spiraled from there.

 

[Barncat]

Good luck with your project. The E&C 150/300A recommendation is safe if you ride reasonably.

After careful vernier caliper measurements, I made a 1.25" od x .072" thick shim washer from a bit of steel tubing and installed it in the smaller bearing end housing, since that gave the best rotor to stator alignment. There is now no end play in the shaft.

Unfortunately there is no way to make any fine adjustment to the bearing preload like, say, adjusting hubs or headsets, because of the very strong cogging torque on these motors. Backing the 4 long thin screws off a bit that hold the motor together yielded no difference in perceived torque to turn the sprocket by hand.

Put it back on the silver bike and rode 20 miles around town and it seems fine. No quieter though... will keep an eye on it. Can always swap better bearings in if need be.