Folks - Amidst the loadshedding that I am sure is trying every single South Africans diligence to the upmost (even those with backup power systems!) - I noted the following when I helped out a good mate with his VII inverter last night. This backup power system was initially installed with a manual start 5kVA backup petrol generator, which via a changeover switch connected this to either utility or standby power. 

It was then modified to have the Axpert as providing automatic backup in event of AC power failure, but the generator input into the system was retained, albeit that this would feed into the Axpert in the event that the batteries would need to be charged from the STG. 

In the past - the Axpert did not recognise the STG as a power source for which we believed it was out of tolerance (in terms of the AC power source frequency). I suggested that he do the following;

1) Lightly load the petrol generator (with a fan heater) to get its voltage regulator circuit to kick in which brought down the AC power line frequency from 53Hz to 50Hz. 

2) We also changed the AC source (menu #3) from UPS to APL which on selection the inverter accepted the power source. It was noted prior that the LCD alarm indication would flash as well as the graphic showing the input AC 'sinewave' graphic. Once the inverter accepted the AC input source - the additional load on the gen was removed. 

I'd be curious to hear your comments on the two pointers above - it is understood the APL setting provides a wider AC power input window. Does this apply to the mains input frequency too? 

Look forward to hearing from you

Vaughan

 

32 minutes ago, VaughanT said:

I'd be curious to hear your comments on the two pointers above

Agreed. These are in my FAQ #7.

33 minutes ago, VaughanT said:

it is understood the APL setting provides a wider AC power input window. Does this apply to the mains input frequency too?

Yes. The AC input range setting also affects the synchronisation code, which will affect whether the AC-in is rejected as unusable or not. I suspect that this has more to do with frequency slew rate (rate of change of frequency, cycles per second per second), although a really bad figure like 53 Hz could well be automatically rejected regardless of slew.