MAC motor slips but apparently in good condition

E

elt93

10 mW
Joined
Jul 21, 2016
Messages
33
Hi Guys,
2 days ago I was riding my ebike which is equipped with a MAC Motor, 40A Infineon controller and 58V battery. When inputting a throttle signal while at zero velocity, I felt a bang in the back wheel and the motor did not go. I went on the side, raised the back wheel to allow it to freewheel, expecting that the gears were broken but everything worked fine and I was then able to ride it and go home. Since then, it randomly slips when accelerating from zero speed. Meaning that upon a throttle input it will sometimes go perfectly fine and other times the MAC will make a noise as if rotating inside its casing without transmitting any torque to the wheel. Sometimes this happens silently, other times with a few banging noises. I opened the motor today and looked at the gears' teeth and everything looked fine. None of them seemed chipped or damaged. Has anyone of you ever had a similar problem? What could this be due to?
Thank you for your help!
 
as amberwolf said, that's the freewheel for sure. 40A and 60V gives over 2kW. that can be too much for the freewheel.
depending on the age of your motor, there are different versions of the freewheel as well, the later being stronger. maybe contact em3ev for spare parts. they have got direct contact to the factory.
 
Regarding that I have only been using it three months and will need at least this kind of power. What other motor would be suitable for 2 to 3kW without ever having to worry about it breaking down for normal city road use. I have just seen the Crystalyte crown motor but these seem complicated to acquire, are there equivalents mass manufactured in China, acquirable through alibaba for example?
Thank you again for your help!
 
elt93 said:
Regarding that I have only been using it three months and will need at least this kind of power. What other motor would be suitable for 2 to 3kW without ever having to worry about it breaking down for normal city road use. I have just seen the Crystalyte crown motor but these seem complicated to acquire, are there equivalents mass manufactured in China, acquirable through alibaba for example?
Thank you again for your help!
Click to expand...
2kW imho is over the MAC's limit. 3kW definately is. i'm sure, if you open it, you'll see dark brown windings. geared hubs just have a problem to get rid of the heat. so they are limited to below 1kW if you want to be 100% sure that you won't have heat issues over a long period.
if you hot rod them for a few miles they may survive 2-3kW for some time, but not for very long.
look for the tangent drive, or lightning rod's kits if you're looking for mid drive kits, or some cromotor, mxus, or qs205 if you look for DD hubs. all mentioned can run 3kW ALL DAY LONG (and much more if you know what you're doing) 8)
 
More likely you sheared the axle key. Like its supposed to do if you romp on it that way.

Pop it open, and I bet you see the key is cut in half. But with enough spin, it can still get enough friction to turn the wheel.
 
Thank you very much for all your answers. I just did a few tests and I think it is the clutch. However, this just outlined the problem that I was overpowering the MAC. I am lookins at the MXUS 3000 and it seems very interesting. What controller can I use plug and play with it between 40 and 60A? Can I keep the Infineon 12fet that I am using now or are there more appropriate ones for the MXUS 3000?
 
The V2/V3 clutch is available from EM3ev for $40 plus shipping.
 
elt93 said:
I am lookins at the MXUS 3000 and it seems very interesting. What controller can I use plug and play with it between 40 and 60A? Can I keep the Infineon 12fet that I am using now or are there more appropriate ones for the MXUS 3000?
Click to expand...
sure you can use the controller. and sure, there are better ones to use, depending on what you want and need. i like the kelly controllers. or the adaptto which is sine wave for silent operation and has torque throttle. a little costly compared to the super cheap xie.chang controllers though.
 
.
elt93 said:
Has anyone of you ever had a similar problem? What could this be due to?
Click to expand...

Yep.
Bike is a Surly ICT Fatbike with a MAC 12T in the rear. Same configuration, 40A - 60V

The clutch cannot handle the heavy weight of the bike, it slips intermittendly or completely when starting from a standstill with reasonable throttle:
# If it slips intermittently, it sounds and feels if the gears are loosing some teeth under load
# If it slips completely, there is a whining sound when the motor spins

I've tried a spare clutch, same thing happens. No problem when the bike is rolling. Condition is getting worse over time.

As a result, I've redesigned the whole MAC to accomodate for a decent FKNS 6206 2RS by GMN that can handle 148Nm torque :mrgreen:

.
 
I have a six pound 250W Bafang SXWH that I'm running with various batteries, between 36V and 52V. I put it together to make a bike that will be easy on the battery. It's 40 lb w/o battery. I keep it pretty slow normally, but I do look at max speed when I try out a different battery.

I've noticed a few pops from the motor at 22 mph. No slip or change in momentum. I thought that was my sensorless controller not keeping sync with the hall sensored motor. After reading the above posts, it's probably the clutch?
 
I have had the same thing happen with my MAC 8t with the controller at only 25amp, only 44v. Had it with other ones too. Not clutch or gears, not the ring gear as it's different motors. Was going to ask but think it was a bad connection. Cleaned connectors and seemed like it was gone. later it did the same bang, pop, fizz and it was dead. re-twist the throttle and it's ok. So I think it's more wiring or controller than the motor. No warning, it just happens. Ridding along and it does it or ride along slow down, try to accelerate and it's dead. May be the HALLS? do they go funky, work and don't work?

I'm still looking but right now for the last 3 weeks been one handed due to a stupid thing. I tried to stop a dog fight. Boy, one thing you don't wanna do is, break up two bitches fighting. Had surgery on my lt thumb, torn tendon. @ more weeks in a cast and then therapy. So snow on it's way, before I get testing. I hate ridding in that stuff.

Dan
 
A 45mm dd like muxus is Heavy. I have one. Spinningmagnets is using a 35mm 1,500 watt d.d that will be my next motor. Or something smaller then a 3,000 watt. The 28mm 1,000 watt is to ez to melt. So compromise is 35mm.
 
When you shear the pin, the motor inner core spins, but only the friction of the axle allows the gear and clutch assembly to turn, turning the wheel.
Inside, the wires don't spin, as they never do. Its just the magnet ring in the core that spins, without turning the gears.

You hear it in there whirring happily away, and the wheel may turn, or not, depending on how the chunks of the torn up key jam up on the axle and clutch.

I jumped a geared motor till it sheared the key, so that's how I know. The key is supposed to shear before the gears break teeth. Maybe it does, maybe it does not. But it's supposed to.
 
if i REALLY is a sheared off pin, than there's an easy solution for it: let it slip until your battery is empty. the friction will produce enought heat to weld both parts together. problem solved :)
but i guess that's not the fact. i assume it's the freewheel.
and you will only know if you open the motor. i did it over a hundred times. for me it takes less than 5min to do it ...
 
999zip999 said:
A 45mm dd like muxus is Heavy. I have one. Spinningmagnets is using a 35mm 1,500 watt d.d that will be my next motor. Or something smaller then a 3,000 watt. The 28mm 1,000 watt is to ez to melt. So compromise is 35mm.
Click to expand...
i have a hs3540 in a 20" wheel with moped tires. if you keep it at under 2kW, preferably 1.5kW they will stay in the happy zone forever. but don't feed them with something like 3-4kW or they will overheat within a short time.
 
FWIW, both of you running the motor on more watts than I'd advise. If reliability is the goal that is.

The main reason I thought pin instead of trashed gears or clutch, is that is sort of fixed itself. Not sure if that's possible with trashed gears or clutch. My only experience is shearing the pin by jumping and landing with the throttle on till it broke.
 
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