Revision: 1511 Author: sebastien.lelong Date: Sat Nov 28 07:32:08 2009 Log: JSG fixes..... http://code.google.com/p/jallib/source/detail?r=1511
Modified: /trunk/include/external/motor/period_skip/period_skip.jal /trunk/sample/16f877_period_skip.jal ======================================= --- /trunk/include/external/motor/period_skip/period_skip.jal Thu Nov 19 15:09:18 2009 +++ /trunk/include/external/motor/period_skip/period_skip.jal Sat Nov 28 07:32:08 2009 @@ -4,25 +4,26 @@ -- -- This file is part of jallib (http://jallib.googlecode.com) -- Released under the ZLIB license (http://www.opensource.org/licenses/zlib-license.html) - +-- -- Description: AC induction motors are low-priced, very reliable and widely available. -- This library provides a way to control the speed of these motors, if they have reasonably -- angular momentum. - +-- -- -- Explanation: this is *NOT* phase control: http://en.wikipedia.org/wiki/Phase_control -- Phase control makes a lot of noise, both audible and electrical. - +-- -- -- This is deliberate skipping of half-waves. There are only 100 half-waves per second -- @ 50 Hz and bit-fine control of motor speed would result in long duty cycles (2.55s) -- with varying motor speeds and audible pitch change. -- So we keep the period cycle at 32 half waves, with 8 duty cycles that only differ -- one half-wave to minimise audible noise. -- Electrical noise is minimized by zero-voltage switching. - +-- -- Sources: -- Fairchild Application Note AN-3004, http://www.fairchildsemi.com/an/AN/AN-3004.pdf -- http://www.sullivan-county.com/ele/triacs2.htm for schematics and examples how -- to generate a zero-crossing signal. +-- -- speed duty cycle on duty cycle off ======================================= --- /trunk/sample/16f877_period_skip.jal Fri Nov 20 13:34:51 2009 +++ /trunk/sample/16f877_period_skip.jal Sat Nov 28 07:32:08 2009 @@ -4,12 +4,13 @@ -- -- This file is part of jallib (http://jallib.googlecode.com) -- Released under the ZLIB license (http://www.opensource.org/licenses/zlib-license.html) - +-- -- Description: AC induction motors are low-priced, very reliable and widely available. -- They are often used for pumps and fans. They are hard to control, mostly with expensive -- frequency converters. This application show how to fine-tune the speed of such a motor, -- up from 0 RPM to 99.6% of full speed, without the electrical noise of phase control and -- without large duty cycles of varying speed. +-- -- select PIC include 16f877a -- You received this message because you are subscribed to the Google Groups "jallib" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/jallib?hl=en.
