Hi power,Three phase dimmer

[vertebro]

ok i will have to built 3 of them then,ill post the results,now how can control the 3 dimmers at once with just one potentiometer?

[kam]

Use 3 R13's, one for each controller, and then use one potentiometer. I think this should work.

[vertebro]

hi everybody,I just build three dimmer circuits,one for each AC phase ,they work great!
Now I have two questions....how can i control the 3 channels at once with just one potentiometer?
I did try the option of three R13 and one pote but didnt work thy dont dimm all togheter.
is there any way to replace the 9 Volts transformers? they are big space consumers
for selecting each channel i did try disconecting thenumber 4 pin of CI555 but instead of turn the output off remain on full ,so then i just cut the ground of the opto led and work fine.I will post pictures of the proyect soon

[kam]

So, it actually works....

First, you can use the same transformer along with the zero crossing circuitry (thats everything between R1 and Input 2 of the 555) for all 3 dimmers. For the control, the single pot with the 3xR1 should definitely work. If not, try by adjusting R9. There are also triple potentiometers (one shaft controls 3 potentiometers one on top of the other) but it would be such an overkill and probably a bad design.

[vertebro]

you mean one transformer for 3 circuits?
the big problem is that i must deal with 3 phases
funny things happen when i connect one pote,cause i must conect the center terminal
to all the 3 circuits but what should i do with Vcc and Ground??
since my AC source is phase shifted not all function as an unit when i dimm
one lamp dimm,lamp 2 stays on,lamp three is off.....
using one transformer in wich phase should be connected R,S, or T??

[kam]

Ohhhh sure yes! 3-phase you mean. I thought one phase but 3 different circuits. In that case you could do other tricks. You can use for example the transformer only for power supply, and find other means of zero cross detection. It will not be easy though and i do not have something ready. There are ways to get zero cross directly from 220V. For example, you can rectify the 220V with 400V rectifier. Then use a resistor do drop current (say 22K 5W) and then a clamping diode to your 12V DC. I have not test this! You need to probe it with your oscilloscope.

[cheerio]

maybe you want to isolate this stuff. check this out. i did not test this circuit yet but it might do the job.
http://www.dextrel.net/diyzerocrosser.htm

[Sir N]

Hi,

maybe you want to isolate this stuff. check this out. i did not test this circuit yet but it might do the job.
http://www.dextrel.net/diyzerocrosser.htm

I can vote for that circuit!
It's brilliant thought out (wish it was my own brain child ) and I have used it with slight modifications, mainly to make a more narrow ZX-pulse.

Anyway, it's far better than tapping a ZX pulse via a transformer, as the latter alters the phase and hence the ZX point on the secondary side (with respect to the primary side).

[vertebro]

but if i replace the transformer with this circuit ,how do i get the power source for the 555?
any suggestions or drawings about how to replace the old zero crossing method by this one?

[vertebro]

how can i set a min an max light intensity?
im using a 5k potentiometer but i dont want to get the 100% (80%would be nice) at the lamps at the en of the pote neither o%(i need 10-15%) light at the begining

[cheerio]

https://en.wikipedia.org/wiki/Voltage_divider
i think the knowledge of the voltage divider is what you need here

[vertebro]

Thanks a lot Master....!!!!!!! 

[cheerio]

you should post your new circuit when you are ready. so we can check if it is flawless

[kam]

and BTW, the AND must be placed before the R10

[Sir N]

but if i replace the transformer with this circuit ,how do i get the power source for the 555?
any suggestions or drawings about how to replace the old zero crossing method by this one?

Might be too late, but here's an almost complete schematic and a bit of description as well.
If you wanna give it a go, I'll patch it up to completion (3 trimmers and a decent voltage control circuit), wrap it in a tutorial text and, if time permits, I might make up PCB's for it in a modular way - 3 identical boards plus a PSU/terminating board.