Hub Motors: Electrical Question

[electricpedals]

Hi,

we are going to use the MBG36F as a pedal power generator for our mini cinemas that have gone to the far reaches or the planet to support education!

http://electricpedals.com/2012/02/17/pedal-powering-hope-for-apes/

However, I'm not familiar with the AC output of the MBG36F.

Can someone tell me how many phases there are?

How many Bridge Rectifiers are required to convert the output to DC?

Thanks
Colin

[Cornelius]

The MBG36F are a geared motor with freewheel, so it's not suitable as a generator, unless you manage to lock the freewheel function. I think there are someone here that have done that.

That said, all brushless motors from gm are 3-phase, so you'll need 3 bridge rectifiers to get max dc out (Which should be 1ph. ac x 1.73. (approx.)

[electricpedals]

The MBG36F are a geared motor with freewheel, so it's not suitable as a generator, unless you manage to lock the freewheel function. I think there are someone here that have done that.

That said, all brushless motors from gm are 3-phase, so you'll need 3 bridge rectifiers to get max dc out (Which should be 1ph. ac x 1.73. (approx.)

Bit late for that, we've already had it working:

http://www.flickr.com/photos/electricpedals/sets/72157628440431505/

All you have to do is spin it backwards!

Thanks for the electrical advice, we were only using 2 bridge rectifiers (it was pretty good with just two).

Out of interest, once we've wired up the missing phase what difference will it make?

[Cornelius]

You should be able to get the full 250W, which are pretty much what a strong human can do on a pedalgen for a shorter time, and you should also notice a much smoother performance with all 3 phases in action.

Just want to mention an example for the wiring: (assuming Red, Green and Blue phase wires...)

Bridge 1:
 red, green

Bridge 2:
 green, blue

Bridge 3:
 blue, red

... as an example...

[electricpedals]

Thanks Mate, much appreciated!

[Morgen 3Eman]

If you look at the wikipedia article for "three phase bridge rectifier, you'll see how to wire two bridge blocks to rectify three phase. 

You may be able to get a three phase diode stack from a car alternator repair shop pretty cheap. 

TTFN,
Dennis

[Bikemad]

You really need something like this:


Click image for more details

What would I do without eBay?

Alan
 

[Morgen 3Eman]

And so cheap!

TTFN,
Dennis

[Leslie]

Another option is to get a throttle controlled variable regen controller.  It will cost you 50ma to run but at least you can tune your back resistance to a sane level.

Most if not all standar Ebike controllers will work at 12v if you bypass the logic voltage resistors or switchmode regulator, some have switchmode, and others use ressitors to a Lm317t linear regulator.. I think they are all protected by a linear regulators just the same. 

[Leslie]

Rod at EV power Australia has these old GM contoller that fail too often.  He still may have an old box of them and h sells them for $10 and is good for experimenting on these things.. 

The old GM controllers allow brake switch function to disengage the motor function while the thtrottle operates as a variable regen controller.

A 12v battery is going to land some heavy ass regen through a straght diode bridge to the battery from an ebike motor so you need either a bigger volt pack or be able to adjust the regen to a practical level.  12v devices are much more common to find.

These old regen controllers have a resitor to linear regulator to the logic, one only need to add a wire past the resistors. Use a diode to block regen from entering the pack and just patch the inputs to solar panel controller between the blocking diode and controller and feed it back to the battery to keep the 12v system from overcharging .

 

[Leslie]

Might work, as is depending on the solar regulators blocking and switching functions.,

Set your resistors to operated the fet to switch on at 17v.  The point of the fet and the dumpload is when the solar charger disengages the regen voltage will ramp to exeed the limits of the input of the solar regulator.  There will be spikes and it will continue to create resistance on the motor well after the battery is full.

The kettle element, they are usually rated at anout 200 watts, which should proved the pedeler ample resistance for exercise.

The diode blocks Power out of the controller to the battery and channles current through the solar regulator.  The regen is enough to keep the controller powerd up when this occurs. 

With some tweaking this concept should work for anything from pedal generators to wind generators.