Pardon my spoon in your plate, but cannot understand the degree of complication here.

When the motors were pulled out from the hard drives, the circuit that does the three phase conversion was left behind, on the hard drive PC board. Now the task is trying to gather other parts and find the way to run the motors with the perfect parts sitting nearby in the junk box ?

Miguel

 

Externet, you are correct to some extent, but...
The circuit boards that control the drive are all SMT devices, which are VERY small and would be very difficult for a novice with only hobbiest tools to deal with. The PCB traces are extremely narrow, densely packed, and the boards are multilayered, making tracing out the circuit a genuinely bewildering chore. Components in such assemblies may be "house marked" or proprietary in an attempt to mask the real function.

However, there may be some useful intel to be gleaned by examining the PCB.
For example, I just looked at the PCB of an older Maxtor 30GB ATA/133 drive, and where the spindle motor connects to the PCB, the terminals are labeled:
MTR-C
MTR-B
MTR-A
CT
Which to me indicates phases C, B, A, and center tap, respectively.

 

Hello Sgt.
To put the motor to run, the board does not need to have the IC removed from it.
Does not matter at all how fine the traces are, if it is surface mount or whatever.

The only thing to be done is to connect the supply to the board, and only in few cases (brands) find the datasheet for the IC to enable its operation without the rest of interactive circuitry. You use the circuit on-the-board, not extract the IC from the board.
Miguel

 

Hey Miguel
Your assertion may be true, if one can find just that section of the board which controls the motor and speed! This would likely be comparatively easy to do on drives that were made in the 1980s instead of the last 10 years. The level of integration has become extremely high, and everything is uP controlled.

I just got done attempting your suggestion on my Maxtor drive. Two of the ICs seem to have proprietary markings, because I couldn't find datasheets for them. I might dig out some older drives later on.

 

I once made a parallel port-controlled set of halfbridges, and managed to run the spindle motor at fairly low speeds like 5rpm or something like that. One of the problems was that i never managed to have only two pins energised and one idle (impossible with push-pull follower -like connection).
The other proble I had was the huge instability of timing in windows, so it ocassionaly stopped and only vibrated back and forth.

 

externet is fairly right. I have seen lots of sites that recommend his approach, and I may do it in the end. One of my problems is these drives are hot pluggable SCSI drives and do not have a separate power supply.

Also, the size of the controller board from a hard drive hinders the usefulness of the salvage. The motor itself is small, and theoretically can be put in a small unit as needed. If it can be got to run at speed, then a series of reduction gears or belts may make it useable. Having to also rely on managing the bulk of the controller board, which serves no other purpose at that point other than to run the motor, makes it awkward.

besides, its more fun this way.

Kubeek, I have seen the parallel port thing to. I'd rather try to get a stable run in a standalone unit.

 

You could use some simple microprocessor to drive three N and three P devices (bipolars or mosfets) and tweak the start-up and running parts of the code, so that you get stable outcomes and get the most power or torque available.
There even exist processors with PWM outputs which could make the code really easy.

It certainly won´t be the best of what the motor can do because you don´t have any feedback, but it will be more variable than using the original controller which is only made to start the motor and maintain one speed.

 

is this motor a "stepper motor"? I have seen it described that way a couple of times, but I always thought the stepper was the head control actuator.

I saw this forum with a circuit diagram for a stepper motor control circuit.

http://www.aaroncake.net/Circuits/stepper.asp

Does this related?

 

No, it's either a 3-phase AC motor or a BLDC (Brushless DC) motor. Stepper motors really can't be used in such high-RPM applications, as they produce their maximum torque at zero RPM. A stepper motor's torque decreases as a function of RPM.

 

Yes, lostow. The circuit in that link IS for a stepper motor.
Miguel

 

OT: head control actuator is NOT a stepper motor (at least in drives since like 1993), it is a coil suspended in strong magnetic field.

I saw only one drive with a stepper motor moving the coils, it was by two belts on a shaft

 

But is the spindle motor a stepper motor? I swear I have seen at least six websites that refer to the spindle motor as a stepper.

Very confusing.

BTW, does anyone here use qucs on a mac?

 

Not on a hard drive. Not recently.

3-phase or BLDC for the spindle drive, voice coil for the head movement.

Now for floppy drives - yes on both counts. Floppy drives are low speed (300 RPM) so they could use steppers for spinning the disk (if the manufacturer so desired) and they still use stepper motors for head movement.

The ancient CD-ROM drives - yes, steppers were used there, too. I paid $200 extra to have a single-speed Sony CD-ROM supplied with my '93 Gateway 486-66. A double-speed CD-ROM drive was $800, which I decided to wait on. I paid an extra $200 to upgrade the memory from 8MB to 16MB. Six months later, the price of memory quadrupled due to a typhoon hitting Japan and destroying a number of manufacturing sites.

Back in 1980, I upgraded my TRS-80 Model 1 (Z80 cpu running @ 1.77MHz) with a Lobo Drives interface that allowed me to expand RAM from 16kB to a whopping 48kB, and actually add floppy drives and HDD's to it - for the bargain price of $459. I spend another $630 on three BASF 5-1/4" FDD's, each with their own linear power supplies in their own cases, with the familiar grey ribbon cable stringing between them, which had the capacity to store 240kb worth of data on formatted disks; SSDD.

I made inquiries on purchasing the latest and greatest gizmo; a hard disk drive that had the astonishingly gigantic capacity of FIVE MEGABYTES! How could one EVER fill up a drive that HUGE? And FAST... my goodness, it left even floppy disks in the dust.

In 1980, I received a quote for a FIVE MEGABYTE HDD...
The bargain price of $9,999.00 (I'm not kidding - that's what they cost back then!)

Two years later, I was in a computer surplus shop, and saw a huge pile of 5MB HDD's that they were trying to sell for $50 each. I resisted the temptation to buy a dozen of them. Or any, for that matter.

 

Back in 1980, I upgraded my TRS-80 Model 1 (Z80 cpu running @ 1.77MHz) ...

Ahhhh... the TRS-80... now that takes me back... TO ELEMENTARY SCHOOL!!!!

Where in this homily is the Vic-20 or the C-64? I preferred that to the TRS-80 because of little graphics icons you could us on the keys.

I always get a kick out of Intel or Microsoft sponsored programs that give the "history" of the PC and start with "In 1982, the first personal computer blah blah blah..." referring to the IBM PC. I am always like, "Wasn't I learning to program BASIC on TRS-80's before that???

 

It was a first - the 5150 had the first kludged software to decrease performance. Remember the 640K memory limit?

 

I've seen a lot of messages about driving spindle motors, so I dug up a bunch of junk and tried this. It's pretty preliminary, but it works! TI had a circuit for 3 phase VCO using U type inverters, so I went with discrete components to get around the IC issue. The first circuit is based on the common flip-flop (tri flop?) and the second is an inverter. Even has a bit of speed control. Needs some tinkering for pulse width, etc. but things go 'round. It will drive several motors in parallel. All of the components are recycled from scrap tech.
Yes, they are a type of stepper.

 

If you don't mind buying parts to drive the motors, OnSemi has a couple of chips that will do it without much in the way of external components, and they're available as thru-hole types, so you can easily handle and solder them without SMT worries. The spec sheets contain reference designs that could be directly implemented for basic use: http://www.onsemi.com/PowerSolutions/product.do?id=MC33035DW http://www.onsemi.com/PowerSolutions/product.do?id=MC33033DWR2 I'm using one of these as the basis of a unit to control an AC cieling-fan motor rebuilt into a BLDC motor, to use as an ebike motor; should be building and testing the prototype soon.

 

Yeah, I don't mind buying a small component for this. Thanks for the help all.

 

I DID IT!!!!! Here is the proof!

http://www.viciousbunny.net/images/SpinningMotor.mov

 

OK, threw together a 3-phase generator using an LM324. See the attached.

It's output frequency is about 19.2kHz, which is way too fast for your motors. But I did it that way so that it would be easier for you to see the pseudo-sine wave output.

If R5 through R7 are removed, the outputs become square waves and the frequency drops to around 250Hz, which should work fine with your motors. However, the opamp alone won't likely have enough current to drive the motors.

Note that R4 sets the voltage level for the + inputs of all three opamps. This is to allow adjustment for the duty cycle of the outputs; I wanted 50%. In this simulation, I wasn't worried about getting it exact; ballpark was enough. It really needs a 0.1uF cap to ground to eliminate noise.

Note that there should be a 0.1uF (100nF) bypass cap across the supply pins. This goes for just about any IC.

thank you for get 3 phase do u have idea to use these three phases to operate motor 2hp