Aussie SWG Operation vs. US Operation

[aussieta]

Moved from here as it was not related to original thread.. Economics of my SWG

Turned it on for the first time yesterday and noticed that turning the % down changes the actual production rate, cross checked that with the power draw of the unit and power draw went down as % went down indicating that the power unit is using some form of PWM.

our aussie swg seem different to usa swg or just the models i have seen
in usa 50% means turned on at 100% for half of the pump run time
in aus 50% means either half voltage or half amps for the whole run time
i have been to lazy to measure it to see how it works

 

[AusPhil]

our aussie swg seem different to usa swg or just the models i have seen
in usa 50% means turned on at 100% for half of the pump run time
in aus 50% means either half voltage or half amps for the whole run time
i have been to lazy to measure it to see how it works

It's a significant difference that should be covered in the various articles and stickies with country specific info.
Considering the unit can handle up to 8000ppm this particular unit is likely constant current limited making the PWM control on the voltage applied to the plates. but i'm not going to pull it apart to measure however tempting it is to know

 

[Brad_C]

No need to pull it apart, just pop a current clamp on one of the output leads. On a meter you'll see the average current change and on a CRO you should see the output PWM waveform.

My Chloromatic uses the "% of on time in an hour" method, but it also uses a pair of triacs to effect phase angle control to set the cell current and polarity.

The winter mode switch does drop the current down to 85% though.

 

[AusPhil]

No need to pull it apart, just pop a current clamp on one of the output leads. On a meter you'll see the average current change and on a CRO you should see the output PWM waveform.

Nice idea but my unit has a 7 wire plastic encased cable that makes the use of a clamp meter impractical/impossible, i also suspect that this unit is also switch mode ac -> dc before being PWM to the cell, based purely on the size of the main unit, though it is Dang heavy like it has a transformer in it ... i do have a clamp meter that can read DC current though.
I've done quite a bit with both AC and DC PWM control of Christmas lighting but haven't used s CRO for years since the scene moved to serial protocols controlling individual leds.

 

[Brad_C]

Huh, ok I didn't think there was really anything here that warranted it's own thread.

our aussie swg seem different to usa swg or just the models i have seen
in usa 50% means turned on at 100% for half of the pump run time
in aus 50% means either half voltage or half amps for the whole run time

It's just the models you've seen. You can't classify Aus vs USA here as each manufacturer does something slighting different, even within differing model lines.

The electrolytic cell presents a vaguely "ohmic" resistance, so half volts generally means half amps (V=IR).
Yes, there is some non linearity with the rate of gas evolution on the plates and local ionic changes in the electrolyte, but it's so small as to not really being worth considering. More volts == more amps == more Chlorine.

 

[AusPhil]

seems like a good idea to split it out, sorry to take the other thread off-topic

 

[AusPhil]

Huh, ok I didn't think there was really anything here that warranted it's own thread.



It's just the models you've seen. You can't classify Aus vs USA here as each manufacturer does something slighting different, even within differing model lines.

The electrolytic cell presents a vaguely "ohmic" resistance, so half volts generally means half amps (V=IR).
Yes, there is some non linearity with the rate of gas evolution on the plates and local ionic changes in the electrolyte, but it's so small as to not really being worth considering. More volts == more amps == more Chlorine.

Likely it's not purely a USA v AUS

I still suspect that it's a genuine constant current, PWM voltage relationship with respect to the cell resistance as the cell resistance will vary based on the salinity values and that would be the simple way to do it .... simple means less costly