HDD BLDC motor power ratings? - Page 1
Forum section: electronics / projects

author: eneuro
author_rank: Super Contributor
timestamp: April 22, 2014, 07:39:32 pm
content: Hello,What could be power ratings of this small hard disk drive BLDC motors?I've disassembled one from old Segeate 30GB 7200RPM as I know:Its 3 phase wires here with something like serial number, while Google says nothing about thisKF1037SDAPV4.There is about 4.3 Ohm resistance beetween each 3 phase wires.I do not need spin this motor to high speeds, while it will be reused in magnetic mixer, but I wonder how much power those HDD motors might have?Update:I've found some benchmark HDD idle power valuesHowever, I have HDD motor only without any read/write operations...Is it safe to limit current to lets say 1A @ 5V and drive this HDD BLDC without damage assuming it consumes this power for rotation and is driven by 3 phase BLDC motor driver?

author: amyk
author_rank: Super Contributor
timestamp: April 22, 2014, 08:46:24 pm
content: You can look at the power consumption figures for an idea. I've seen ~30W on spinup but doubt it can maintain that level continuously without overheating; typically they are providing continuous power in the 5-10W range.

author: eneuro
author_rank: Super Contributor
timestamp: April 22, 2014, 08:54:11 pm
content: Thank you for hints.Just updated my first thread post and added some HDD power ratings in idle mode.I think, I will limit current to 1A @ 5V and start with 100mA while I do not need high RPM speeds and see what happends

author: ovnr
author_rank: Frequent Contributor
timestamp: April 22, 2014, 09:10:56 pm
content: HDD motors are ridiculously wimpy. They're only there to spin what amounts to a flywheel; there is no load apart from bearing friction and air turbulence.By magnetic mixer, I imagine you mean driving those small teflon-coated NIBs to stir things? It'll be too weak unless you use a VERY small stir magnet. The usual solution I've seen is just to take a decently powerful PC fan and use that - optionally snip off the blades, but you'll probably wreck the balance so badly it won't work well.Or you could be fancy and wind a dozen electromagnets, position them in a circle, and drive those.-

author: eneuro
author_rank: Super Contributor
timestamp: April 23, 2014, 06:07:42 am
content: Quote from: ovnr on April 22, 2014, 09:10:56 pmIt could be too easyEven normal magnets attached to this motor in this configurationcreates something like magnetic clutch when this 5cm (2 inch) rotor with another set of magnets is close to motor disk magnets.This custom magnets rotor prototype should at given RPM speeds create something like liquid bearings at the bottom and maybe it will be able to rotate without any friction (no mechanical contact with box) in glass box filled with water based acid solutions, like 11% H2SO4 I'd like to use for aluminium hard anodizing.I do not need spin it too fast, but I will have better control using this BLDC motor and I'll be able to run it at lower RPM speeds, while PC fan was tricky to spin at voltage <5V in such magnetic clutch configurations, however 4 magnets magnetic clutch worked not so badIt is easy to change motor disk magnetic field configuration simply by changing this disk with magnets, so it will be fun