Author Topic: Controlling a HD motor  (Read 1792 times)

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Offline spizzakTopic starter

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Controlling a HD motor
« on: March 22, 2010, 01:03:44 PM »
Hey all, I'm trying to control a hard drive motor using one of these chips: TDA5140A  /  L6229N. I was wondering if there is any sort of guide that I could use for reference. I have a rough idea of how i'd need to connect it but some help would be good.

Thanks guys.
« Last Edit: March 22, 2010, 01:57:58 PM by spizzak »

Offline Soeren

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Re: Controlling a HD motor
« Reply #1 on: March 22, 2010, 02:53:59 PM »
Hi,

Both chips have application information in the datasheeets.
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

Offline spizzakTopic starter

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Re: Controlling a HD motor
« Reply #2 on: March 22, 2010, 07:11:32 PM »
Yes I realize this, however my problem lies in not being very proficient at extracting information from datasheets as I have not done it very much. What I was asking was if there are any resources that people here know of, or any advice they can give that would help me with implementing this type of driver.

Offline Soeren

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Re: Controlling a HD motor
« Reply #3 on: March 22, 2010, 11:32:56 PM »
Hi,

The Philips datasheet has got a schematic with component values and when you start building, you can ask here if you hit a brick wall - Short of someone actually building it for you, you aren't gonna get it much better I think.
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

Offline spizzakTopic starter

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Re: Controlling a HD motor
« Reply #4 on: March 23, 2010, 12:45:17 AM »
So I can only get the L6229N and not the TDA5140A but the L6229N datasheet shows three connections for the motor, but the HD motor I have has 4 terminals. Does anyone know what the fourth is, or which terminal is for what?

Offline Soeren

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Re: Controlling a HD motor
« Reply #5 on: March 23, 2010, 03:03:40 AM »
Hi,

So I can only get the L6229N and not the TDA5140A but the L6229N datasheet shows three connections for the motor, but the HD motor I have has 4 terminals. Does anyone know what the fourth is, or which terminal is for what?
To be able to make any electronics at all, you need to be able to read the answers you get!
I told you the Philips datasheet has got a schematic with component values - and you say "why can I only use the ST chip"  ::)

Let's be clear, you can use any chip you like, as long as you read the datasheet, but if you need other people to read it for you, you have to take what you can get and I doubt you'll find someone willing to design you a complete circuit just because you don't wanna use the Philips variety (without even explaining what you have against it).

The motor you have is a 3-phase motor, so 3 wires goes to each a winding and the other side of those windings are connected in the motor and brought out as the fourth wire. In the Philips circuit you connect that line to pin 17.
Look at p.9 in the Philips datasheet where it is shown.
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

Offline spizzakTopic starter

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Re: Controlling a HD motor
« Reply #6 on: March 25, 2010, 02:00:23 PM »
Actually, if you'd read my reply you'd see that what i said is "I can only get the L6229N" and that is because the philips one is only available in quantities of 300+

Thanks for your help though, you've been absolutely splendid!   ::)

Offline Soeren

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Re: Controlling a HD motor
« Reply #7 on: March 25, 2010, 05:04:50 PM »
Hi,


Actually, if you'd read my reply you'd see that what i said is "I can only get the L6229N" and that is because the philips one is only available in quantities of 300+
Ah, so that's what you meant.
I took it for a question due to the "So" it started with ("So I can only get the L6229N and not the TDA5140A [...]").
The L6229 has got a schematic as well, but the component values needs to be calculated (as described in the data sheet).

Another thing. You should have a 3-ph. controller somewhere on the PCB that originally drove the motor and it might be possible to find a datasheet for that.
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

Offline spizzakTopic starter

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Re: Controlling a HD motor
« Reply #8 on: March 30, 2010, 01:23:57 PM »
Okay so here's what we were able to do so far:
I am trying to drive a HDD motor using L6229 motor driver. I have made the connections as in the attached image.

I have following questions right now:
I need 4 lines for motor. I have connected 3 of them to Out 1, Out 2 and Out 3. Should I connect the 4th one to ground?
Where do Sense A and Sense B go?
Do I need the Charge pump to drive a motor?
What is the TACHO for and do I need it?
What are RC pins for? Do I need them for this circuit?
Do I need current detection pin?


Offline Soeren

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Re: Controlling a HD motor
« Reply #9 on: March 30, 2010, 08:57:39 PM »
Hi,


Let me start off with some questions:
What revision number is your datasheet?  (It's written at the bottom of page 1, mine is revision 3 from October 2004).
Did you read it?
When you got the HD motor, didn't it have its PCB and if so, what chip is on it?
What did you do with the PCB?


I have following questions right now:
I need 4 lines for motor. I have connected 3 of them to Out 1, Out 2 and Out 3. Should I connect the 4th one to ground?
Which lines did you connect?
How did you find out which to connect?
You are the only one to find out which wire goes to what, use an Ohmmeter and find out which is which.
The fourth wire could be a tacho line, a connection to the center of the star windings or something entirely different.


Where do Sense A and Sense B go?
Datasheet p10, fig. 10 and p18 fig. 24 shows that (fig. 24 is a complete schematic and Table 9, same page, has the component values).


Do I need the Charge pump to drive a motor?
Yes, but it won't do much good when you don't use it to give the needed voltage boost to the gates of the high side N-channel MOSFETs.


What is the TACHO for and do I need it?
For speed control - and since I don't know your purpose, I cannot tell if it's OK letting it run wild (but I'd guess not, as tight RPM control is one of the parameters Brush Less DC (BLDC) motors are chosen for in a HD).


What are RC pins for? Do I need them for this circuit?
A BLDC controller is 3 of the same but separate circuits. Each can only pull the motor a certain distance.
In comedy, timing is everything it's said, but in BLDCs it really IS as close to everything as you can possibly get (it doesn't get funny until the timing slacks, you may say  ;)).
As you can read in the datasheet (p4), one of them is for the current controllers off time and the other is for the F/V-converter.


Do I need current detection pin?
Yes.
And you need the Hall pins as well.
In your "diagram", you have 8 pins "not used", one with a question mark and you're shunting the boot strap voltage to V+.
That tells me that you didn't really care to read the datasheet, or you would know that you need all these pins.

Your M.O. right now should be, apart from studying the datasheet a bit closer, to locate the original PCB, as it may tell you the purpose of the fourth wire as well as contain the Hall elements which are crucial to running the motor.
Frankly, you'd be better off using the chip that the original PCB has got.
If you cannot locate the PCB, you're wasting your time, you can save the motor for the bearings, but you're probably not gonna see it running in any controlled way and you'd probably be much better off with a regular DC motor (or finding another BLDC motor WITH it's driver PCB).

Ask yourself this: Why do I want to use this particular motor type and what do I want to drive with it?
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

 


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