Converting a hubmotor to a middrivemotor

I think you have done a good job in removing any rubbing noises and the high pitched sound is maybe something you can muffle somehow after the motor is firmly mounted in the bike. I know in aluminum boats people like to put either carpet or rubber inside the hull to soften the noise. I wonder if you glued say some 1/8" thickness of rubber to the outside part of the bike you have had custom fabricated for battery enclosure and motor mount. I realize this custom fabrication for your bike will act as somewhat of a heat sink for the motor as well for you but I am sure even a little distance away from where most of the heat gets transferred to you could experiment with some rubber glued or riveted to the aluminum structure. This may be a dumb idea but just trying to think of a way to silence this for you as I know you are concerned with the noise. Looking forward to your progress, keep the good work Izeman!
 
as i can see in the vids, the motor bell is definitely deformed. i would say also the noise is coming from that.
do you have another motor? There is a newer version of the MAC on the market with thinner laminations and holes in the bell - i think you will know this already :)
 
madin88 said:
crossbreak said:
have you tried a different controller?
Click to expand...
the kelly KBSX would be a good choice for this motor i think:
http://kellycontroller.com/kbs48121x55a24-48v-p-528.html

torque based throttle and thermal protection of controller and motor for the win^^
Click to expand...

before i try a new controller i want to test zombiess' throttle tamer and power throttle of my CA. atm i don't feel like it's not controllable in current state. but this may change after some serious test ride.
 
madin88 said:
as i can see in the vids, the motor bell is definitely deformed. i would say also the noise is coming from that.
do you have another motor? There is a newer version of the MAC on the market with thinner laminations and holes in the bell - i think you will know this already :)
Click to expand...
i don't have another motor, but may get access to one. if i can't solve it i will probably buy a new mac, but shipping costs alone have stopped me from ordering so far.
 
izeman said:
yes sure. :) a sine wave controller could help.
Click to expand...
I tested 5pcs of my adapters and 2pcs of it works same (motor BPMII, controller Green Time 45A). IMHO it has no symmetry. I guess a sine wave controller can't help.

BTW I killed 2pcs duralumin adapters and now sure duralumin is not good for it. The axle made a round hole into adapter.

index.php


My first adapters (duralumin) was made on a lathe and I guess some of it have no symmetry. Now I make it from steel by laser cut.

index.php
 
evb thanks for your input. unfortunately i'm not sure that we're talking about the same thing. the noise a sine wave controller could get rid off has nothing to do with the adapter, and the wobble i see on the adapter has nothing to do with everything else.
but i maybe interested in those lasercut adapters. the ones crossbreak made are excellent and are made of hard durable alloy. but if it once may fail it's good to know where to get replacement :)
the new axle i will make will habe a much shorter thread, so the adapter will not sit on a thread but a flattened round axle (not threaded). this will be a better fit without sharp edges and will be more wear friendly.
 
izeman said:
...the noise a sine wave controller could get rid off has nothing to do with the adapter, and the wobble i see on the adapter has nothing to do with everything else.
Click to expand...
sorry, I suggested you troubled big sprocket wobbling and try to solve it by a sine wave controller.

izeman said:
but i maybe interested in those lasercut adapters. the ones crossbreak made are excellent and are made of hard durable alloy. but if it once may fail it's good to know where to get replacement :)
Click to expand...
ok :)

I clamp an assembled adapter by a nut to motor cover (axle bearing), it make exact 90 degrees from sprocket to axle, especially if the central hole is not quite done carefully.
 
evb said:
I clamp an assembled adapter by a nut to motor cover (axle bearing), it make exact 90 degrees from sprocket to axle, especially if the central hole is not quite done carefully.
Click to expand...
Yep.. that is what the "pipe/washer" is used for.. simply keep distance between bearing and adapter+make it 100% perpendicular. Iceman.. your wobble is something spoecially strange.. can't diagnose from the distance.


@evb: I'm sorry, Duralluminium is too soft. I use a much harder alloy with tenisile strength >300N/mm²..sadly it can't be cut well by laser. But that does not matter much. Simply buy a round piece that comes with 32mm in dia already and cut slice with the buss saw.
 
crossbreak said:
Duralluminium is too soft. I use a much harder alloy with tenisile strength >300N/mm²
Click to expand...
What's name of this alloy? Now I use a steel 370-490N/mm² (german analogs - 1.0038, 1.0116, DC03, Fe360B, Fe360D1, RSt37-2, RSt37-3, S235J0, S235J2G3, S235JR, S235JRG2, St37-2, St37-3, St37-3G)

crossbreak said:
Simply buy a round piece that comes with 32mm in dia already and cut slice with the buss saw.
Click to expand...
But in this one piece you can't laser cut middle hole. So you have to make this hole by milling-machine. It's more expensive.
I tried some ways and now I sure laser cut is most cheap way for it.
 
I'm not sure what alloy i used.. think it was 6061. Can't remember sry.

No, you can't mill a double-D hole. simply impossible due geometry. I use technique like "gear shaping" (german: "stoßen") for this.. here is an example video https://www.youtube.com/watch?v=fmTSXNE8OVw

Lasercutting will only work well/cheap with normal steel. But normal steel like St37 should work fine. If you phosphate it later, it wont rust too fast.
 
I used alloy 2024t35, tensile strength >395N/mm², they are dead :)

crossbreak said:
I use technique like "gear shaping" (german: "stoßen")
Click to expand...
I see this method, but can't find this machine.
 
crossbreak said:
:mine twisted the shaft :D only slight imprints noticeable at the adapter
Click to expand...
try to press break on full speed throttle on hanging wheel, I tried :)
 
crossbreak said:
how to you think i got a twist shaft.. 120A phase current on a Code13 is simply more than the shaft/axle can take.
Click to expand...
you tell me. 40a battery and 90a phase at 48v from a stall made the axle snap in an instant. the adapter survived that w/o troubles.
 
guess this was just bad luck. Of course the hollow shaft of the MAC suffers from less material..still it can take the torque+bike /~500N) weight in a hub so why should it not take chain force (~2500N) and the same torque in a middrive?

Maybe chain force was too much for it. As said, bending is no issue for the BPM shaft. It twists before it bends.
 
IMO this discussion is somewhat ridiculous, since at phase amps >80A these motors become horribly inefficient anyway. Lower your phase current..do less stress on chain, shaft and gears...shift a little more often and be pleased by the increased range you get.
 
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