Locking clutch/freewheel in geared hub motor for regen?

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bendik.vignes@gmail.com
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Locking clutch/freewheel in geared hub motor for regen?

Post by bendik.vignes@gmail.com » Nov 23, 2017 10:21 am

I could not find any answers to this question...

Is there any examples of a sucessfull modification of a MAC geared hub motor (or similar) where the clutch/freewheel has been "locked" so that the motor can be used for regen as well?

I have a MAC myself but would like regen...

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Re: Locking clutch/freewheel in geared hub motor for regen?

Post by bendik.vignes@gmail.com » Nov 23, 2017 10:43 am

I tought about buying a spare MAC clutch and try to insert epoxy into it...
Could that work??

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izeman
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Re: Locking clutch/freewheel in geared hub motor for regen?

Post by izeman » Nov 23, 2017 10:52 am

of course it will work. putting epoxy in it may not work though. there is a lot of grease in it. getting all that out before applying the epoxy can be impossible to do.
you can easily weld it all together.
but i wouldn't do that. it will add A LOT of drag to the motor if unpowered. with it's 5:1 gearing the motor runs at quite high rpm ...

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Re: Locking clutch/freewheel in geared hub motor for regen?

Post by Voltron » Nov 23, 2017 12:05 pm

Yes, the few that I read about doing it melted the gears from the constant high rpm with the motor never getting to cool due to the regen.
Not saying it can't be done, esp if you had one with a blown clutch laying around to mess with.

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Re: Locking clutch/freewheel in geared hub motor for regen?

Post by litespeed » Nov 23, 2017 12:29 pm

A geared motor with locked gears is a direct drive motor. Just keep it simple and get a direct drive motor. Available from 150 watts to over 5000 continuous.

Tom
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Re: Locking clutch/freewheel in geared hub motor for regen?

Post by bendik.vignes@gmail.com » Nov 23, 2017 12:57 pm

Thanks for all the quick replies:-)

Drag: when turning the wheel backwards I notice only slightly more drag than my Golden motor DD motor, so I does not consider drag as a major drawback

Locking: Yes welding seems to be a better option than epoxy, thanks!

Melting gears: this seems to me as the biggest issue. I have the newer MAC motor. There was a change in gear types some years ago. Does this matter, or are the new gears just as much exposed to melting..?

DD: yes I would rather like a direct drive motor, but since I allready have a geared one I should use that one...

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Re: Locking clutch/freewheel in geared hub motor for regen?

Post by motomech » Nov 23, 2017 3:21 pm

Over the years, a couple of members here have "locked-up" geared mini motors because of clutch failures and neither of them liked the results.
It's hard for me to see the reasoning of what you want to do, especially since the MAC is a very desirable motor, worth at least 2 times the value of the inexpensive 9C DD motors (since you haven't filled out your profile, we don't know where you are at, but in the States, you can buy a 48V 500/1000 Watt DD kit starting at $150).
Besides, regen is over-rated and most of the time it's biggest benefit is reducing wear on the brakes.
Why not sell the MAC and buy a DD motor?
Or keep the MAC, because after you try a DD motor you may well want to go back to the MAC.
Motomech

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Re: Locking clutch/freewheel in geared hub motor for regen?

Post by bendik.vignes@gmail.com » Nov 23, 2017 5:02 pm

Thanks for sharing your opinions motomech! I live in Norway. Here the market is not as large as in the states, and we have to pay a lot in shipping + taxes when importing things:-/ I bought the MAC realtively cheap at the second hand market (but the motor kit is not used)

I have desided to build the MAC into my bike with or without a locked clutch. I like the idea of charging when braking because here my town we have A LOT of hills. And I wear out my brakes all the time..

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Re: Locking clutch/freewheel in geared hub motor for regen?

Post by izeman » Nov 24, 2017 5:10 am

litespeed makes a valid point: if you want regen: get a DD. if you want a small package sized high torque motor for a bike: go for the MAC.
the problem i see with welded freewheel: you add complexity to such a simple design, which an electric motor is, by adding gears and a freewheel, and then you weld it.
one big issue the MAC (and every other small geared motor) has: they have an additional layer of metal (the outer case) with insulation air between the motor and the case. this makes cooling very difficult. this is no big deal if you keep the power at "legal" levels, but if you start hotrodding it becomes imminent. and if you then weld the freewheel the motor is 100% powered. normally the motor has some time too cool down when you coast or brake, but with the welded freewheel it will jump between motor and generator all the time. and both produces heat. you can choose how much heat, by programming the controller, limiting phase amps and limiting braking power, but why choose the use regen when you limit it afterwards?!

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