Harold in CR wrote:
I believe you are posting on a RC forum, correct ???
If so, I have been trying to understand this electronic stuff, enough, to try to run my Brand NEW 24V 150 AMP Alternator I just had shipped down from the States. If it does as stated, it would make a good candidate for my E Motorcycle or reverse Trike.
I just can't get the Electronic stuff to sink into my head.
Yes Harlod you are right, I was logged in RC group as vytis rex, my youngest son name, aeromodelling is where its all began
Start my first exposure with the BLDC motor in my Airwolf-Trex heli
and my first micro-controlled helicopter in 2007
But then I found that It must more fun being an aeromodelling mechanics
Anyway, Congratulate on your new endeavor in alternator conversion
, will try to help you anyway I can, but first could you be so kind to point me on how to getting those alternator ?
I assumed you already know how to convert the alternator into a brushless motor, but if not then this is the step that you need to take:
1. Remove the Diode plane from the alternator. In the BOSCH alternator, you need to unsoldered 6 wire in the Metal/Plastic diode plane in the back of the alternator, which then will leave you with 6 cable (2 cable each phase, use multi-tester to check which connected to which one), then you need to rewire into star or delta.
2. you need to use the existing brush to supply the rotor, hence you have to keep the integrated regulator and brush intact, but please assure that you cut both wire coming out from the regulator as it will intervene with the rotor supply.
Now you got you self a very powerful alter-motor unfortunately its a sensorless , hence you need to have a speed controller that also support sensorless commutation. In my case, I used a RC car that support both type of commutation. eHirobo got a XERUN controller in http://www.ehirobo.com/shop/product_inf ... ts_id=8727
, it capable on handling 150Amps, and 6S (around 28 Volts max)
or like my eBuggy, you could use http://www.hobbyking.com/hobbyking/stor ... duct=10370
, support 150A but only with 4S voltage handling.
With those controller, you will be able to immediately runs the motor in the sensorless mode, with the option to turn it off into a sensored when you're ready.
Or you could go directly into kelly's controller or other Sensored BLDC Controller by installing hall sensor like I did in this Nippon Denso 35A alternator.
Please note that due to the Claw rotor arrangement you have to install the hall sensor exactly in the middle
On the controller side :
Bob diode from RC group gave me this link (after I manage to figure it out from Atmel application notes), it's provides a very visualization on how the BLDC commutation works:
http://users.tinyworld.co.uk/flecc/4-po ... 031102.swf
As it could be seen, one "electrical rotation" (for 12 pole rotor this would be mean 1/12 mechanical rotation) consist of 6 steps, each steps was represent by different arrangement of which Phase should be connected to (+) positive supply and which phase should be connected to the (-) negative supply, in every step there should be exactly 1 phase connected to (+) and exactly 1 phase connected to (-). To regulate the the power, either (+) or (-) or both supply was not connected continuously but rather only a fraction of time (switched ON-OFF), The power to the motor was then governed by the period of duty cycle (the ON time) this is called PWM. In RC world typically we used 16KHz or 32Khz PWM for some reason.
All step was executed successively according to the direction of the rotation which was triggered by the state change in any of hall sensor.
Below is the typical driver (using both N & P channel mosfet) of BLDC
Q1,3 & 5 was referred as the High Side, which upon ON state will connect any phase to the (+) supply
Q2, 4, 6 was referred as the Low Side, which upon ON state will connect any phase to the (-) supply.
Hence, what a controller do is exactly turning which mosfet ON and which mosfet OFF based on the input of Hall controller, while assuring that none of both High Side & Low Side mosfet in one phase having on ON together as this would means a short circuit
which some times referred as pass-through.
Hope this help you in your new endeavor