F
fritz
Guest
geoff <geoff@nospam-paf.co.nz> wrote in message news:j6mdnSmgJdMeu7fVnZ2dnUVZ_tyknZ2d@giganews.com...
Commmon stepper motors have 1,8 degree steps, while a typical
commutator DC motor has only 3 or 5 commutator segments being
discretely energised per revolution, is that any smoother ????
It all depends on the drive electronics, with the right timing a
'stepper motor' will be far smoother than a commutator motor.
There is really fuck-all difference between what is called a 'stepper motor'
and what is called a 'brushless DC motor'.
Mechanically, they are virtually identical. The differences lie mostly in the
drive electronics for the application, and the way the stator coils are terminated.
The 'brushless DC motor' usually (but not always) has Hall-effect devices
mounted to sense the rotor position and control the phase of the (typically)
3-phase coil drivers, while 'Stepper motors' usually don't have rotor sensors.
Have a look at the May 2008 issue of Silicon Chip, page 16.
Leo Simpson argues that 'In reality, there is no such thing as a brushless
DC motor', and I totally agree that the terminology is misleading.
Why not ?fritz wrote:
geoff <geoff@nospam-paf.co.nz> wrote in message
news:m_mdnXICIObeXLXVnZ2dnUVZ_obinZ2d@giganews.com...
fritz wrote:
Has anyone tried using a stepper motor from a CDROM ?
I have one, it was used to drive the spindle i.e. spin the disk
of a Sony CDROM.
It has 9 windings (coils) on the stator and 6 magnetic poles on the
rotor. (North poles only - 12 N+S in total)
The 9 stator windings are connected to only 3 terminals.
Stepper motor ?!!!
How would you servo control a stepper motor to track a CD pre-groove
?
geoff
Look up 'spindle'. i.e. it spins the disk
The motor I was talking about isn't part of the laser groove tracking
system at all.....
A stepper motor spinning the spindle - that doesn't sound very smooth !
Commmon stepper motors have 1,8 degree steps, while a typical
commutator DC motor has only 3 or 5 commutator segments being
discretely energised per revolution, is that any smoother ????
It all depends on the drive electronics, with the right timing a
'stepper motor' will be far smoother than a commutator motor.
You clearly do not understand the construction of these types of motor.I think you'll find it is a conventional brushless DC motor - not a stepper
motor.
geoff
There is really fuck-all difference between what is called a 'stepper motor'
and what is called a 'brushless DC motor'.
Mechanically, they are virtually identical. The differences lie mostly in the
drive electronics for the application, and the way the stator coils are terminated.
The 'brushless DC motor' usually (but not always) has Hall-effect devices
mounted to sense the rotor position and control the phase of the (typically)
3-phase coil drivers, while 'Stepper motors' usually don't have rotor sensors.
Have a look at the May 2008 issue of Silicon Chip, page 16.
Leo Simpson argues that 'In reality, there is no such thing as a brushless
DC motor', and I totally agree that the terminology is misleading.