Motor Speed
The graphic is below, the delay is the lenght of the pulse. My problem is the speed, I want the speed around 15.000RPM like is shown in this picture http://www.datarecoverytools.co.uk/wp-content/uploads/2009/08/spindle-speed.jpg
Did you do your math?
Check your numbers: 15000 revolutions per minute. How many per second? How many ms per revolution?
Check your labels: does your hard drive do 15000 RPM? Those are rare. Most modern disks for PCs do 5400 RPM.
Check your coil configuration. My disk has three wires plus a central wire. The three coils are wired in a “Y configuration”. Each coil in my disk appeared to be divided into three coils. That’s nine coils in total. That takes nine pulses per revolution.
At 1 ms per pulse (and no delay between pulses, as your diagram suggests) those nine pulses would translate to 9 ms per revolution, 111 revolutions per second, 6660 revolution per minute.
Your numbers might be the exact same. Don’t count on it.
Motor Speed
Let me try to explain what I want, I think I’m confusing you . I have a spindle motor wired in a “+ configuration” (12 coils) , 3 wires for the coils and 1 common , I trying to obtain the faster rotation, like a hard disk works, but I just obtain this speed in the video that I recorded. http://www.youtube.com/watch?v=6Zp0elG9xP8.
need some help
here’s what i did:
1)i set the clock around 0.25Hz then i started the 74164 shifting.here i had 47µF and 10nf in parallel.
2)i set R1 around 1K and then and then connected a pot at R2.
3)then i removed the 47µF.then the hard disk motor started squealing at a high freq. then i increased R2 and gradually the freq. decreased and then after some value of r2 the clock suddenly switched off every time i did this.and beyond that value the clock never turned on again.then when i turned back the pot (decreasing value).the clock starts after some value just as earlier.and during which the motor starts and after some value of pot. then gains some RPM and the the motor stops and the squealing takes over and the motor stalls.i tried decreasing the R2 very slowly but still the motor starts and gains some RPM and then halts again.
can you please tell me what’s the problem.and can you please tell me if the value of r2 has a max. value beyond which the clock stops.is what i am doing wrong, because i coould’nt get decreasing value of capacitors?
i’m using an SMPS to power up the the circuit is it okay?because even without i sparking the pin2 of 74164 the IC starts automatically as soon as switch on the circuit.
thank you.
Again, you are asking me to guess
You mention resistors by number, but you don’t tell which circuit you’re discussing. Don’t make us guess.
You say your “clock switches off”. Do you mean your motor stops running or do you really see the clock pulses die? How do you see that?
By “squealing” you mean “turning really fast”, right? Or is it just making high pitched noises?
Did you ever consider that my circuit is not the best way to go? I mentioned this several times across this page…
Further thoughts…
Excellent article, it certainly answered my search for what pins to apply voltage to to make the motor turn!
I have 2 memories of things which could help this idea evolve? Many many years ago I built a graphplotter based on 2 stepper motors, my father built the mechanics (he was an engineer) and I messed around with the electronics. My Z80 based microprocessor system had a Parallel IO port so it was easy to generate the the pulse sequences.
A) I think the 5V outputs then went into a power transistor wired as “open collector” which basically meant that a low voltage, low current could switch a higher voltage/current, the transistor behaved like an on/off switch.
B) the Spec Sheet for the stepper motor recommended that the coils be energised singly, and in pairs, alternately: i.e. based on Red/Amber/Green the sequence would be R, RA, A, AG, G, GR. When 2 coils are energised the motor only makes half a step. This makes the stepping twice as granular, so your motor would require 18 steps in the sequence to make one turn. My stepper motors were 180 steps per turn, and designed to turn slowly and precisely, I suspect that with only 9 steps per turn and a motor designed to turn fast then it’s only about maintaining the inertia at the correct rate so I doubt this is an improvement. It would also require diodes or AND/OR gates to help generate the pulse sequence.
Anyway, I have 10 or so old drives so I may have a play with this. The immediate advantage of these being step motors is that it would, in theory, be possible to
1) rotate them precisely in sync;
2) wire them in parallel
Of course, I have no idea why I would want to do this, but it seems like a fun engineering objective to spin shafts at 7,000 RPM then have them wind down and still be precisiely aligned…
One last question, on some drives the motor is held in the frame on a large flange, screwed down. On others the motor seems mounted directly in the HDD frame: any idea how to get these motors out of the frame?
Thanks again.
quick reply from Madrid
No I don’t know how to ge them out. They might be press fitted. So brute force is authorized. If you destroy them, there is no loss. At any rate you will gain knowledge. Make sure to share. You now know where.
On the the other thing: I never know WHY i do things like making stupid stuff. Or rather: the why the end result has reason to be. It’s about doing it, not having it.
this is pretty old, sorry
this is pretty old, sorry for the bump
my mate sent me that schematic ages ago, but why wont a simple 555, and 4017 combination work?
Bumping is encouraged around here.
Nobody say it won’t work, did they?
Electronics is trying, and
Electronics is trying, and trying is learning, and learning is gaining experience, and gaining experience will lead you at last to new ideas. Kudos, Rik, trying to get on the bottom of something is the right way:)
Removing motors cast in HDD.
Don’t laugh but the simple way is to cut them out. I do, just cut wide enough to dress things up, then drill mounting holes in the corners. Oh yeah, I cut them square. Also you should tape the motor to keep FOD, (er… Foreign Object Debris, but you probably knew that.) from getting in around edges.
I was trying this out
I was trying this out… but for some reason… the sequence stops after a random time interval… its not a fixed interval…
Motor control
As this is a brushless motor is it better to send logic 1 out on all 3 pins and energise each coil by enabling and disabling each line in turn?
You can then change direction by reversing on of the phases
Then pwm modulate the chips power