 Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me. |
Forum Index : Electronics : EGS002 / EG8010 as variable frequency drive control
| Author | Message | ||||
| hary Regular Member  Joined: 15/04/2019 Location: FrancePosts: 89 |
Hi all. Has anyone ever played with the EGS002 / EG8010 variable frequency feature ? -using external I/O configuration ? or -by modifying internal register through serial port ? I would be very curious to use that variable frequency feature to use as a variable frequency drive for induction motor. The EGS002 / EG8010 has a V/f=constant feature that seems to be a good addon for softly start induction motor. What do you think ? |
||||
| Warpspeed Guru  Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
Single phase induction motors are not really suitable for speed control. The only reason they work at all is by some "trick" in creating a virtual rotating magnetic field that does not really rotate. Either a second out of phase winding fed through a capacitor, or a shorted turn around the edges of the pole pieces has to be used to even get the motor to start. Whatever trick is used for starting and running relies on some cunning design and tuning, which all falls flat on its face if you reduce the applied frequency by very much. A three phase induction motor is a very different beast that DOES produce a true rotating magnetic field, and works very well speed controlled. So you find all VFDs are for three phase induction motors only, none are made for single phase induction motors, which cannot really work. Cheers, Tony. |
||||
poida Guru Joined: 02/02/2017 Location: AustraliaPosts: 1418 |
Hary, have a look at https://www.thebackshed.com/forum/ViewTopic.php?PID=109054#109054#109054 I found it works fine. wronger than a phone book full of wrong phone numbers |
||||
| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
The VFD will work fine, but its the induction motor that will not be happy at high load and low speed. Cheers, Tony. |
||||
| hary Regular Member Joined: 15/04/2019 Location: FrancePosts: 89 |
@poida : thanks for the link and info. @Warpspeed : Yes, I understand what you mean. Running a single phase induction motor is almost like riding a push bike with only 1 leg. At quite high speed, it might be ok, but at low speed, it won't. It's like a 1 cylinder engine, it needs a good flywheel and some rotation speed ! I've been driven blind by what was written in page 16 of the EG002 datasheet : https://www.lz2gl.com/data/power-inverter-3kw/eg8010_datasheet_en.pdf "8.7 VVVF (Variable Voltage and Variable Frequency Mode) To ensure motor's electromagnetic torque is constant while varying frequency, setting VVVF="1"will keep the value of V/F at a constant, Voltage is adjusted as the output frequency changes. When VVVF="0", output voltage is not changed when frequency varies." So I wonder the use of that feature for that board. Have you heard of the EGS031 board ? I think it's equiped with a EG8030 chip but it's very difficult to find any documentation. |
||||
| Warpspeed Guru Joined: 09/08/2007 Location: AustraliaPosts: 4406 |
Don't really know Hary. Could it be to drive an electromagnet for a vibrator table perhaps ? One dimensional in and out movement and variable frequency with an almost constant drive current could possibly be made to work. Cheers, Tony. |
||||
| poida Guru Joined: 02/02/2017 Location: AustraliaPosts: 1418 |
no probs Hary. here is the EG8030 datasheet. Language is Chinese EG8030-EG.pdf and Russian eg8030_datasheet_rus.pdf and the Russian pdf translated by Google. It helps. Archive.zip wronger than a phone book full of wrong phone numbers |
||||
 Print this page |
