Hi everyone, help with a brushless controller

[Pablo_1985]

Hi, i´m Pablo from Spain, first of all congratulations because the forum, i thing it´s simply great. I´m electronic engineer, so i´ll fell glad of helping anyone with theirs projects.

Ok, i´m making an electric bike, but i´m trying to take all the parts from yunk, now i have about 4 brushless bosch motor, but i don´t know the specs from them. I know they have neodimium magnets, and they work at 24 volts, they were from a bosch robot or something...it has an axel with 20mm of diameter, so i thing it could have lot of torque. some photos...

http://i522.photobucket.com/albums/w348/anguita1954/P1030354.jpg
http://i522.photobucket.com/albums/w348/anguita1954/P1030348.jpg
(i don´t smoke, they aren´t mine)

Ok, don´t worry about breaking the motors, they cost 0 € and i have more of them, so, before i broke them, you can see there are 3 big wires, and 2 more little wires, but, i don´t know how could i do for doing it work, all the electronics and so died in the right moment when you open it, but it seems to be all the control inside the motor...i can cut and cut until i can take the 3 phases from the motor, and what i supose it is all the wires from hall effect sensors. so now the questions i have...

Does your motors has hall effect sensors? or are they controlled with back efm?...
maybe i could put an optical sensors to know where the rotor is in any moment, if it is necesary to put sensors because back efm could be not be aply on this motor.

I´m looking for a brushless controller and then forgive about all the electronics that is inside because furthermore you can see it is with epoxi, lot of epoxi, so it´s really hard to take a look to noting...i thing it is about 1000w or 1500w , just because the size, but i can´t find any brushless controller wich works at 24v and this power, ¿do you know any controller with this characteristics?

First of all i´m going to do it work with arduino, some mosfets...but i will controll the frecuency by handly, like the old cars wich you couldn´t acelarete at maximun, instead of this you have to push the pedal softer or harder depending of what did the car wants...i hope you understand what i mean... i´m not going to have at the begining any program against misfire and so.

Please forgive all the mistakes i could do for writing in english

Best regards from spain!

EDIT: does anyone knows this or have any experience working with them?
http://www.onsemi.com/pub_link/Collateral/MC33035-D.PDF
EDIT2: has anyone prove to put the controllers in parallel? what if i put 4 or 6 of this?
http://cgi.ebay.com/24V-250W-brushless-controller-for-E-bike-scooter_W0QQitemZ300276900706QQcmdZViewItemQQptZScooters

 

[fechter]

Most bike motors use hall sensors. You can get a controller that uses sensors cheaper than a sensorless. If the sensors are not useable, you could use a sensorless (back EMF) type controller. Sensorless controllers are very common for RC model aircraft. There are a few sensorless bike controllers around too. Here is are some RC controllers:
http://www.castlecreations.com/products/phoenix_hv_series.html
Keywin (ecrazyman) also has a sensorless adapter that works with his controllers.

You could add sensors to your motor, but it looks like a lot of work. If you heat the epoxy to around 100C, it will get soft and rubber-like. It is possible to dig out the epoxy with a sharp knife or screwdriver when it is hot. It gets rock hard when it cools off. You can soak it in boiling water to heat it. It would be good to use the existing sensors. If the sensors are still usable, you could use almost any brushless bike controller.

That motor looks like it is made for high rpm (>3000). It may need a lot of gear reduction to use with a bike.

 

[Pablo_1985]

thank you very much, i think i could do an optic driver wich give the same signal than the hall effect sensor, so i will try this because in big motors doesn´t used to use back emf (thank you, i know it in spanish "fuerza contraelectromotriz", but i said it wrong everytime!) , because all the electric noise...furthermore, i see the link, and they are really expensive...that makes me think about doing it my self, because the integrated circuit that i put, only cost 4€ (about 6 dolars), and i can get the rest of components freebie...but it´s sooooooooooooooooooooooooo boring.....

oh! i forgot to talk about regenerative braking, i also would like to implement it on the bike, and i think just with a rectifier and charging the bateries with pwm (100% duty cicle for maximun braking, 0% no braking...), it could be really easy and it could be attached after the complete construction, has anyone tried it?

Ok, so if i achieve to make my motor sensored, where could i found a controller with the specs i said?

Thank you really much, and best regards.

EDIT: maybe the controllers has the regenerative braking so i wouldn´t have to make it, could it be?

 

[dnmun]

how do you know that it is a brushless DC motor? i am sceptical.

 

[fechter]

I'm sure it's brushless. The magnets are on the rotor.

Yes, you could make an optical interrupter that would provide the same signal as the hall sensor. You could also place hall sensors on the edge of the stator and pick up the signal from the edges of the rotor magnets (easy). Typical hall sensors are equivalent to Honeywell SS40A or SS41.

I would recommend this controller:
http://endless-sphere.com/forums/viewtopic.php?f=9&t=8428
also discussed here:
http://endless-sphere.com/forums/viewtopic.php?f=2&t=8317&p=133533#p133533
Also available on eBay from ecrazyman shipped direct from China.

These controllers can do regenerative braking already. Adding regenerative braking is not so easy if the controller is not made for it.

 

[Pablo_1985]

The first time, i disasemble the motor and try to check the electronics, i´ll try to memove the epoxi with a heat gun, and it waqs too hard, because there is too much epoxi, and also it has platic parts wich were destroyed...

The brushless motor are like synchronous motors, in fact, they are synchronous motors, but instead of creating a static magnetic field with a solenoid (usually in rotor), it is created with magnets, the rest is very similar, typically, a 3 phase solenoids (usually in stator), wich creates a magnetic field that is turning (this was revealed by ferraris, and that´s why there is a ferraris´ theorema ). And because of we are using magnets instead of solenoids, we don´t need any power suply for the rotor, as we needed when we had a solenoid, so we don´t need any brush because there are no mobile parts wich need a power suply, so....that´s a brushless motor.

Guys thank you very much, i just have signed up in this forum, and i couldn´t expect a warmer welcome.

 

[Drunkskunk]

Welcome to the forum.

I think what you have pictured there are the servos from a robotic assembly arm. They use a stepper motor, and are very similar to a typical brushless motor, but not exact in that the windings are diffrent. It is possable to build a stepper motor driving circuit and run them as a regular motor, but there efficancy is low in that form. The best way is to rewind the coils and run them as a conventional brushless.

I'm not an expert on how that is done, but many people over on RCgroups.com rewind CD rom stepper motors to use as 3 wire brushless, and have some great posts as to how its done.

 

[Pablo_1985]

i thing it´s not a stepper motor, because i´ve just checked that the windings and they are in a delta configuration (star or delta, i´m not sure if you call it like that "A", "Y"), and in a stepper motor the windings are separated, and you can turn on or turn off each winding, by separated...look at that.

http://www.todorobot.com.ar/informacion/tutorial%20stepper/stepper-tutorial.htm (spanish look at the pictures)
http://en.wikipedia.org/wiki/Stepper_motor

In a brushless motor, it is diferent because it´s a trifasic system, you can´t excite a winding without exciting the rest of winding, and when you power it up with a trifasic sytem, you get a magnetic field wich is turning dependind of the numbers of poles frecuency...

Another link in spanish but also the importan things are the pictures...(why i couldn´t find anithing about ferraris teorem in english?)

http://www.tuveras.com/maquinasca/maquinasca.htm

I said i´m electronic engineer, but, ok, i´m just finishing, so don´t thing in me like an old man who everything knows about electronics, because i have just a littles of experience, i say that because i re-read my post and it sounds like it is not! hahaha (in spanish we laught like "jajaja"), in fact i´m "only" 24 years old.

Best regards

 

[EbikeMaui]

It looks like a 4 or 8 step motor that needs a 4 step controller. More likely a delta with neutral timing.