Conhis mini motor - anyone played with it?

[neptronix]

http://www.conhismotor.com/ProductShow.asp?id=85

I've seen this motor quite a few times and have wondered about it more recently -
thinking that maybe it'd be an ideal motor for a crank drive setup -
or maybe just spin it super effin' fast ( 72v? ) and run it to the rear wheel via a reduction drive..

looks like it may have less or equal the amount of poles as the infamous Crystalyte 4xx?
looks like it may have a 35-40mm stator too? not as big of a diameter as other hub motors, but
am i right in thinking that wideness of the stator + lower pole count than most DDs can
make for some good power extracted out of this motor ( relative to it's size anyway )
if spun up on some high volts??

 

[iperov]

2013 conhismotor MINI-DD with disc brake

42mm magnet width

 

[spinningmagnets]

My interest in the Conhis mini DD-hub is that it is only about $110, and can run much quieter than a geared hub.

I like the idea. If you could get freewheel sideplates easily and cheaply, you could simply DP-420 a freewheel onto the right side so it wouldn't unscrew. When the freewheel wears out, replace both the sideplate and freewheel.

Or, flip it over and reverse the direction (that way a driven freewheel on the left side would tighten onto the threads), if the halls are neutrally timed, it will be as efficient in either direction. Perhaps if not neutrally timed: use a sensorless controller and set the three phase wires for reverse operation. With a watt-meter of some sort, it should be easy to compare forward unloaded watts to reverse unloaded watts.

A third option might be to connect a 15T-22T fixed sprocket to the disc brake flange, and have the motor drive a 12mm jackshaft (sprocket could be on the left or right side).

Fourth option: If the fixed sprocket was on the right (motor reversed), it could drive the rear wheel directly (crossbreak style), and a left side freewheel could be driven by a left-side chainring Hollowtech-II crankset.

http://www.endless-sphere.com/forums/viewtopic.php?f=28&t=7192&start=25#p401162

 

[cwah]

I actually purchased this motor from them last year and used it on my brompton with the 24V model:

I overvolted it to 80V to be able to reach 30mph on 16" wheel.

What's great is that it's really silent so it's nice to drive.

The con is that it's not a very efficient motor, and it gets hot pretty quickly. Maybe because I live in city and do a lot of start and stops.


So I changed to a geared motor (Mac 8T), and now I have a much more efficient one that accelerate much faster and stay cooler over time. The biggest issue with the Mac: The noise

 

[spinningmagnets]

Do I smell a Conhis "oil cooling" thread in the brewing?

Their website lists 24V, 36V and 48V versions. Since I believe they are likely to be wound to the same 15-MPH (or nearby) top-speed...the 24V version would be the fast kV, and the 48V version would be the slow kV

16-inch wheel, 80V, 30-MPH, sooo...what's the loaded kV of the 24V model?

 

[cwah]

I'd to answer you but I don't know what is a loaded KV. How do I measure that?

 

[spinningmagnets]

kV is how many RPMs a motor provides per volt that is applied to it. "Unloaded" is with the wheel in the air spinning freely. The RPMs will be slower when under a load, but since a heavy person on a steep uphill will be slower than a light person on flat land, the loaded RPMs will vary and are inconsistent, but...right now all I have is the loaded results from an "average" user profile.

First, a 16-inch wheel at 30-MPH is_________
(16-inches diameter X 3.14 = 50.24 inches circumference. One mile is 63,360 inches. 63,360 divided by 50.24 =1,261.15 revolutions per one mile.

There are 60 minutes in an hour, so 30 miles in one hour is [1/2 mile per minute, or one mile per 2 minutes], soooo...1,261.15 revolutions every two minutes/or 630.57 revolutions per minute [take a sip, scratch chin...]

630.57 revolutions per minute (RPM) X 60-minutes = 37,834.39 revolutions per hour, divided by 1,261.15 revolutions per mile = 30-MPH)

A 16-inch wheel at 30-MPH is 630-RPMs (21-RPMs per one-MPH)...since this was achieved at 80V, we divide 630 by 80 = a loaded kV of 7.88 RPM's per volt.

If this is true, and IF they all have the same top-speed, the kV of the...
24V = 7.88
36V = 5.91
48V = 3.94

 

[spinningmagnets]

Is the spin-direction reverse-able? and also...are the side-plates switchable (left to right and vice-versa)?

 

[cwah]

Thanks for this very nice and detailled explanation. This is then the kv on a loaded speed of 65kg rider.

However, i rarely managed to stay long enough on straight road to know the exact max speed. It's probably a little bit higher than 30mph

I don't have a speed meter with me currently, otherwise I'd have confirmed it.

Spining direction is not reversable. I'll take picture of both side to check if side plates are reversable

 

[ROG130]

this sounds like something i am looking for i was thinking about the 8fun motor
be good to have some more info on the small light weight motors with good power output
looking for something to put into my new full carbon frame build
as i think my hs4080 is going to be to big

 

[cwah]

Took it out of dust:

Looks like the cover might be inter-changeable.

 

[iperov]

So....

Mini-DD magnets 42mm, poles 25, D=136mm, weight 4.5kg conditionally 159 sq.mm magnets per KG of motor

Big-DD magnets 30mm, poles 27, D=229mm, weight 6.5kg conditionally 122 sq.mm magnets per KG of motor

I planning 2WD conhismotor mini-dd, by 10A each, with 20A phase each.

 

[ROG130]

well i found this video conhis mini motor super fast you got to love it
be good to fine him on e.s and ask him how he is getting on with it
http://www.youtube.com/watch?v=1Ro2eD88StM

 

[crossbreak]

be aware than the spockes flange is part of the motors back iron - so it is iron The stator carrier is made of iron, too... almost completely made of iron, this one that explains why it feels heavy like lead, small but heavy. Mine is almost 2 years old now and took a lot of rust there at the spokes flange... sorry for no pic

I agree it is not efficient, espacially in larger wheels. more than 20" makes no sense for this motor. I laced it into a 26" :x feells like almost no acceleration, even at 50amps phase.

This one could be really valueable in a middrive.. on a large lathe, a lot of useless iron could be turned off. A stator carrier made off alloy and a missing spokes flange will drop it's weight to somewhere around 3kg, i guess. With 0.5mm lams, it should get lossy at more than 250Hz, that is 15000 e-rpm or 600rpm, if it has 25 pole pairs. A 6:1 reduction to the cranks seems to be perfect for such a middrive... tried it with 3:1 which was fun already, but had no big lathe to turn off the useless iron...
But with a Hammerschmidt crank gearbox that gives 1.6 reduction and a 48T/13T reduction form motor to Hammerschmidt, we get a 6:1 ratio.... the 13T freewheel could fit onto this motor with some rework.

Their website lists 24V, 36V and 48V versions. Since I believe they are likely to be wound to the same 15-MPH (or nearby) top-speed...the 24V version would be the fast kV, and the 48V version would be the slow kV

As far as I kno, there is only one KV (10.7KV accourding to conhis website). The 24V "version" just spins half of the rpm, the 48V one does Maybe it can be converted from Star wind to Delta, to get a 18.8KV. That would suit perfect for a 48V middrive with 6:1 reduction to the cranks.

 

[spinningmagnets]

Found two other DD motors for potential mid-drive.

The Bafang SWXK is a front DD hub, and I like how the phase wires exit the case from the side instead of through a hollow axle, but...it does not have a disc brake flange, and also it is extra tiny, 134mm diameter.

Just found the Smart Pie from Golden Motor, controller can be excluded or built inside the hub (like the larger Magic Pie), it has a 188 diameter (roughly 18mm is spoke flange, so potentially 170mm, or 6.7-inches, a half-inch more than a dollar bill), and the phase wires exit the side instead of the axle, plus it has a disc brake flange to attach a track cog to...

 

[spinningmagnets]

9-Continents company is bringing back a small-diameter DD hub, similar to 408?

http://www.9continent.com/nkt/products_show.asp?id=100

 

[davec]

very interesting- it'll be neat to get these into the simulator- lately i've been thinking about making a very light weight efficient rig using a road bike- i dont think these hubs like hills too much but on flat they are pro and i imagine would require a bit of peddling at times

http://www.ebay.com/itm/ebike-front-wheel-hub-motor-kit-/251487537030?pt=Cycling_Parts_Accessories&hash=item3a8dd34786

98SWX36
Diameter(mm)98 Width(mm)100 Rated output power(W)250 Maximum output power (W) 500 Maximum output torque(Nm) 35 V: 36 - not bad for a 1.6kg motor if these claims hold any truth