# Ebike Alternator Motor DIY



## nozza36 (Apr 3, 2009)

BOBDIODE , you are a star ! i've been slowly planning a bldc
motor build but was worried about what to use as a main shaft for the rotor , you've just given me the perfect solution for a sturdy build , 
i'm off to the scrapyard to pick up a lorry alternator ! 
MANY THANKS !


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## BobDiode (Apr 16, 2009)

nozza36 said:


> BOBDIODE , you are a star ! i've been slowly planning a bldc
> motor build but was worried about what to use as a main shaft for the rotor , you've just given me the perfect solution for a sturdy build ,
> i'm off to the scrapyard to pick up a lorry alternator !
> MANY THANKS !


With a little machine work on the shaft two of the shorter housing halves can be used with a 17 x 40 mm bearing on each side. Good Luck!
http://www.hydrogenappliances.com/cores_and_coils.html


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## gostadler (Aug 10, 2009)

BobDiode sure came up with a good idea.

Has anyone thought of using one of those old Chrysler Corp pancake alternators, some were like 100 amps, reason is, the rotors are very large in diameter and the same magnetic field / current might give you a very much higher torque because of the leverage advantage of the large diameter rotor.

[email protected]


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## BobDiode (Apr 16, 2009)

You need a PM rotor to make it worthwhile.
You can buy a brand new PM alternator with the strongest magnets available on E bay for under $200. 1/10 of it's power will flip over a bicycle.

http://www.rcgroups.com/forums/showthread.php?t=905411&page=11


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## Rollie (Oct 28, 2009)

Does this controller pictured need position sensors or is it sensorless? If it needs position sensors would it work to take an inexpensive rc motor and marry it to the back of the alternator for a simple position sensor?


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## BobDiode (Apr 16, 2009)

Rollie said:


> Does this controller pictured need position sensors or is it sensorless? If it needs position sensors would it work to take an inexpensive rc motor and marry it to the back of the alternator for a simple position sensor?


 The Castle Creations HV 45 amp ESC is Seensorless and programable. A 3 wire hook up to the 3 phase wires.


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## Fujiyama1 (Oct 8, 2009)

HI guys , new to the scene, are you converting the lorry alternator into a 3 phase motor , do you need some feedback from the shaft
re
Barry


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## Fujiyama1 (Oct 8, 2009)

hi yes it does need feedback , is it easy to build
Barry


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## BobDiode (Apr 16, 2009)

Fujiyama1 said:


> hi yes it does need feedback , is it easy to build
> Barry


A sensorless controller is all you need. If you make a magnetic PM rotor or buy a Delco PM alternator the PM rotor is already installed and there is no need to waste power energizing the field coil.
If you do want a sensored controller to commutate the rotor you must make a hall sensor board using three $1. hall sensors that can be epoxied to a fiberglass board and mounted in the right place for 120* timing.
This is a small 5 lb Ford PM Alternator / Motor with a hall sensor board and hall sensor controller used for a Electric bike that goes 45 MPH.
http://www.youtube.com/watch?v=Q5kwH1Nkpr0

This is using 2.5 amp hours from a 5 ah 66.6 volt lithium battery pack. The 5 pound motor was made from the smaller old style Ford alternator with a 12 pole PM rotor.
http://www.youtube.com/watch?v=cxj4i5VLxf8

The picture below is a Delco with and without a PM rotor. Notice that with the Claw Pole rotor without a PM rotor needs a pill magnet disk used to trip the hall sensors. A sensorless ESC is much easier and does not need hall sensors or a commutation disk, but you will not get low rpm torque because of errors in commutation. Sensord hall sensors are preferred for smoothness, efficiency and high torque from a standing stop.


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## BobDiode (Apr 16, 2009)

BobDiode said:


> A sensorless controller is all you need. If you make a magnetic PM rotor or buy a Delco PM alternator the PM rotor is already installed and there is no need to waste power energizing the field coil.
> If you do want a sensored controller to commutate the rotor you must make a hall sensor board using three $1. hall sensors that can be epoxied to a fiberglass board and mounted in the right place for 120* timing.
> This is a small 5 lb Ford PM Alternator / Motor with a hall sensor board and hall sensor controller used for a Electric bike that goes 45 MPH.
> http://www.youtube.com/watch?v=Q5kwH1Nkpr0
> ...


I am in the process of making a new 14 Pole High Grade Magnet Rotor to slip into a Delco 12 Si Alternator using the original stator and have a very powerful 8 pound BLDC Motor. I will also have some Hall Sensor PCBs to mount for hall sensor controllers. Options would be higher voltage, thin silicon steel lamination stators for a few different voltages. RPMs and torque levels (kv and Kt).

This 5 lb motor takes vary steep hills utilizing 3 motor and pedal ratios. The 8 lb version will require only a single chain ratio to have more torque and efficiency with out the use of a 3 speed internal geard hub. When I get the New Protype built I will post a Video of it in action.

Hill climbs all over 30* Grades
http://www.youtube.com/watch?v=-UnMvqcAeeE

Dirt riding up a 1000 ft elevation rise using 166 watt hours of battery power
http://www.youtube.com/watch?v=cxj4i5VLxf8

Ultimately this will be the motor for this type of Free-Ride Mountain Bike
*http://tinyurl.com/35bv3rn
http://tinyurl.com/34uylby*


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## jetmoose (Aug 16, 2016)

Hey Diode Bob,

Will this alternator plus this ESC give 7000 watts at 140 amps and 48 volts?


http://www.ebay.com/itm/Wind-Turbin...268996?hash=item2810116bc4:g:D9MAAOSwFqJWnZMG


http://www.ebay.com/itm/CASTLE-CREA...NIX-140A-HV-/262514013819?hash=item3d1f0df67b

Also what lipo battery pack to use? How long would a charge last running full power?

This would be about 9 horse power motor right? For about 10 pounds plus battery right? Also your hookup video links are not working. Do you disconnect the diodes to convert to motor mode?


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## dcbusman (Aug 13, 2013)

Im trying the sensorless version first as its more in my skill level, how much voltage do i apply to the field brushes, I have tried 1.2 to 6v and it tries to start but just sort of rocks back and forth, Im applying the power thru a small dc to dc adjustable reg. The alternator is an old Delco like in your pic, with the diodes removed and my controller is a 72v brushless duel mode sensor or not. My battery is a Sun E cycle 60v ( 71.6 fully charged)
Here is a link to it https://www.youtube.com/watch?v=-Zl9VyEcnyc


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