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Topic: Frequency Question (Read 6578 times) previous topic - next topic

RobertEagle

I have found these X-BLDC Brushless motors and ESC's.

These motors are made by an exclusive team, from what I have heard, in Germany, and have ESC's on I2C working at 1Khz, and 14-pole brushless motors.

Here's the link:
http://www.x3d-shop.de/shop/article_17188146/X-BL52S-Motor.html?sessid=19qaqOLcO3VBpPcxVVi7uwSEbx73EESJgtFFmkLE4seX2XnBTjLsdcnpsywQJZnU&shop_param=cid%3D107%26aid%3D17188146%26
http://www.x3d-shop.de/shop/article_17188145/X-BLDC-Brushless-Regler.html?sessid=19qaqOLcO3VBpPcxVVi7uwSEbx73EESJgtFFmkLE4seX2XnBTjLsdcnpsywQJZnU&shop_param=cid%3D107%26aid%3D17188145%26

What do you think about this? Is curious, because I see no datasheet, they don't write anything about their products, and somehow they are selling them. (From what I have heard, these systems are custom made, and by this, their products are so expensive).

Thank you,
RobertEagle

dhenry

Quote
their products are so expensive


But are they any good?

It is very easy to make expensive stuff. Not as easy to make quality stuff.

RobertEagle

This I was asking you.
I don't know nothing but the interface speed. Nothing more.
Yes, they are exaggeratedly high priced, from my point of view, and even I don't know if they are good at something.

My goal is to make something like those from the MIT, or if it is possible, even better. I know that their quadcopters (from the MIT) have ESC's running at 1Khz, and I believe that the only way of reaching their performances is to match their physical quadcopter's characteristics, thus I need this type of ESC's and motors.

dhenry

Quote
My goal is to make something like those from the MIT, or if it is possible, even better.


It is possible and likely.

The avr based esc is practically in the public domain and you can find everywhere. Many firms offer public domain mcu-based BLDC controller code that you can adapted to AVR, or any other chips you wish to use.

Having said that, bldc control is actually quite complicated. Without good understanding of analog / digital electronics, I suggest that you don't set too high of an expectation for yourself.

RobertEagle

Can you give me a start point? Like a tutorial, or a website were I can read some technical data about this type of ESC's and BLDC motors.

Erni

Take a look in the rc forums, for example rcgroups has quite a few DIY ESC threads in the multirotor section:

http://www.rcgroups.com/aircraft-electric-multirotors-790/

And the DIY electronis

http://www.rcgroups.com/diy-electronics-199/




dhenry

Because bldc controller is such  a huge market and one that is naturally gifted for mcus, all MCU manufacturers have numerous app notes on them. Atmel has quite a few, ST has a fairly well written and documented library on BLDC control for its stm8 and stm32 chips. That would be where I start.

The undisputed king  here is Freestyle but unfortunately they write cryptic app notes on this.


Erni

And because ESC's are mass produced and therefor relatively cheap, and many are based on Atmega8, there are many tutorials to reprogram an existing ESC to do what you want.

RobertEagle

#53
Oct 05, 2012, 03:38 pm Last Edit: Oct 05, 2012, 08:43 pm by RobertEagle Reason: 1
Get it.

Now regarding the BLDC motors.
What is more efficient in terms of performances, responsiveness and torque? The 2-pole motors or having 3 (to 8 poles)?
From I think, having more poles, you'll need higher frequencies between the ESC and the motor, therefore more precision at controlling the motor. IS that right?

dhenry

Quote
What is it


It is the 'B' in "BLDC".

RobertEagle

I'm sorry, but I don't understand what you are suggesting. Can you be more clear?

Thank you,
RobertEagle

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