Comments for ProdMod (tm)

Comment on micro mosquito RC flying helicopter (vs havoc heli picco z) by scalco

scalco — Fri, 02 Oct 2009 01:17:03 +0000

thx .. very informative & jus what i was lookin for.

Comment on Zoom-O Ball Launcher by Blip Toys only $9.99 by noignArromo

noignArromo — Tue, 14 Jul 2009 13:56:21 +0000

Админ я не могу зарегестрироваться может я просто не то делаю ?

Comment on Take apart that PC Box Fan- see what’s inside brushless DC motor by omarai

omarai — Tue, 07 Jul 2009 03:04:28 +0000

I made my own blog going further in the electronics involved. Take a look at http://omarai.wordpress.com/.

Comment on Take apart that PC Box Fan- see what’s inside brushless DC motor by Omar

Omar — Mon, 06 Jul 2009 03:53:03 +0000

Time goes by and knowledge is gained. Some of my comments in reply to “jesus”’s first comments were “moderated”. I’m very upset because I haven’t had the chance to freely express myself, as jesus had, but that decision isn’t mine. Extracting the main idea of what I said in that missing comment, that chip is a chip as some logic reside inside it. It is an integradted circuit that it has output transistors, switched by the hall effect sensor by means of a predriver. Arrogance isn’t a quality, so lets say that if an assumption of a “two transistor combination” is made, there has to be somw logic to control them (to do the switching) as the transistors by themselves can’t switch freely.
I went on investigating those chips and I found that every cooler’s RPMs can be sensed, even though the “yellow wire” isn’t present. The yellow wire signal is just one of the transistors “on-time” pulse, so with another transistor and a pair of resistors, the output signal that is generally connected to the motherboards, can be generated. I’m thinking about testing one of those chips and put togheter a note with the information I found up to know. So if someone needs or wants to know how they work, send me an email and I will gladly share it.
Regards.

Comment on Take apart that PC Box Fan- see what’s inside brushless DC motor by Omar

Omar — Wed, 01 Jul 2009 03:22:14 +0000

adding to what I’ve already said.

Questions:

Does anyone know what that chip transistor is? —->

“two-coil fan drivers”

Anyone know what the laminates probably look like?—-> No idea what you are referring to…laminates look like laminates, thin pieces of metal.

Anyone try giving less or more than 12Vdc to obtain speed control?—-> The correct answer could be found if you knew something about the bldc motor. But supposing that the fan has specified its operating voltage along with the current I wouldn’t go any further for a continuous operation as it has been design to work under those conditions. Higher voltages will make the IC logic blow (above 18V typical for those chips, absolute maximum rating) and could make the wound coils overheat and thus reducing the bldc life expectancy among other side effects. Lower voltages are allowed, but there’s a minimum voltage needed so that the bldc defeats the forces that oppose (like load inertia) to the torque that the motor produces. Typical values for a 12V fan with current consumption below 200mA is 7V to start spinning smoothly. Speed control can be achieved with PWM controlled switches (fets, transistors,…) without reducing the voltage applied to it (simplest way). Voltage regulators are another option (less efficient, higher power dissipation). The ultimate control is achieved through coils switching (most complicated but most effective and efficient).

Hope all this info helps…I’m not an expert but I try to do my best according to the depth given here.

Comment on Take apart that PC Box Fan- see what’s inside brushless DC motor by Omar

Omar — Tue, 30 Jun 2009 21:35:16 +0000

If it’s free, don’t make complaints. I bet this article helped a lot of people to understand at least something about fans, even though information isn’t 100% accurate. It’s a starting point for a discussion.

Comment on Take apart that PC Box Fan- see what’s inside brushless DC motor by Omar

Omar — Tue, 30 Jun 2009 21:30:18 +0000

I’m sure you have already made it work. But if you haven’t yet, all you need is an external power source (transformer + rectifier or switching) and some electronics if you want to be able to vary their speed. The rest are screws and a mounting hole.

Comment on Take apart that PC Box Fan- see what’s inside brushless DC motor by Omar

Omar — Tue, 30 Jun 2009 21:27:30 +0000

The sensor showed in the pictures isn’t just a hall effect sensor. It has 4 leads and there are no transistors to interact with the coils…it’s an integrated controller with hall sensor included.

Comment on Take apart that PC Box Fan- see what’s inside brushless DC motor by Omar

Omar — Tue, 30 Jun 2009 21:24:13 +0000

James, a PWM signal of low enough frequency can be applied to vary speed without harming the internal components. The low pass idea isn’t good by itself as the current needed by the fan will discharge the capacitor faster than it is charged. What you can do is use the “average voltage” after the low pass filter as a reference voltage to drive a transistor or operational amplifier.

Comment on Take apart that PC Box Fan- see what’s inside brushless DC motor by Omar

Omar — Sun, 28 Jun 2009 18:42:09 +0000

I think I found what those 4-leads chips are: two-coil fan drivers. They are a one-chip solution for driving two coil
brushless DC cooling fans. The IC contains a Hall-effect sensor, dynamic offset correction and low side output drivers. Based on the information provided by the datasheet I found and the connections that the fans I have show, I think that both chips are equivalent. Hope this helps anyone interested in the subject. Regards.