Tuesday, January 29, 2008

[oopic] Re: Induction Motor control using ooPIC

--- In oopic@yahoogroups.com, "john.willium" <john.willium@...> wrote:
>
> Hi Dennis,
> I want to change the speed of the induction motor according to an
> analog signal. I can give this signal to I/O line 1 to A/D conversion.
> So according to the value (0-255), I want to change the speed of the
> induction motor. For example, 100 rpm min & 1500 rpm max.
>
> The thing what I want to clarify is whether ooPIC can be used for this
> purpose. Bcoz I'm familiar with ooPIC & know this is capable of
> controlling servo motors.
>
> Regards,
> John

You are trying to make a Variable Speed Drive (VSD) and this takes a
LOT more electronics than an OOPic. Especially if the motor is more
than a tiny fraction of a HP.

You need to be able to create a square wave of appropriate voltage that
varies in frequency from 3 to 60 Hz (90 - 1800 RPM 4-pole motor). This
squarewave needs to be able to drive whatever current the motor
requires.

Normally this process goes: bring in AC, rectify it to DC, filter,
switch to motor windings.

Further, VFDs normally drive 3 phase motors although the second
reference below shows driving single phase motors.

There are references all over the place but here is one from Microchip:

http://ww1.microchip.com/downloads/en/DeviceDoc/01033B%2041.pdf and
http://ww1.microchip.com/downloads/en/AppNotes/AC%20Induction%20Motor%
2000984a.pdf

See also

http://www.aosmithmotors.com/html/motorDoctor/Understandingmotorspeed.ht
m

In the end, you won't be using an OOPic for this job.

Richard


Yahoo! Groups Links

<*> To visit your group on the web, go to:

http://groups.yahoo.com/group/oopic/

<*> Your email settings:
Individual Email | Traditional

<*> To change settings online go to:

http://groups.yahoo.com/group/oopic/join

(Yahoo! ID required)

<*> To change settings via email:
mailto:oopic-digest@yahoogroups.com
mailto:oopic-fullfeatured@yahoogroups.com

<*> To unsubscribe from this group, send an email to:
oopic-unsubscribe@yahoogroups.com

<*> Your use of Yahoo! Groups is subject to:

http://docs.yahoo.com/info/terms/

No comments:

Post a Comment