SUA1500 noisy inverter

dario_ramos_apc · ‎2021-06-29

I have an 1500VA UPS that is noisy when running from batteries and with some kind of loads.
It is noisy with computer loads but not with linear loads like lamps.
The noise is not continuous.
From my technical experience it seems to be current pulse interruptions.
The UPS is not overloaded because this behaviour starts with 450 Watt computer load.
Based on this idea I compared the inverter of this SUA1500 with other of an old SU1400 that I have also.
In the SU1400 inverter I count 16 power transistors. In the SUA1500 inverter I count 8 power transistors.
Is there some one who can confirm that SUA1500 inverter has only in fact 8 power transistors?

dario_ramos_apc · ‎2021-06-29

I have an 1500VA UPS that is noisy when running from batteries and with some kind of loads.
It is noisy with computer loads but not with linear loads like lamps.
The noise is not continuous.
From my technical experience it seems to be current pulse interruptions.
The UPS is not overloaded because this behaviour starts with 450 Watt computer load.
Based on this idea I compared the inverter of this SUA1500 with other of an old SU1400 that I have also.
In the SU1400 inverter I count 16 power transistors. In the SUA1500 inverter I count 8 power transistors.
Is there some one who can confirm that SUA1500 inverter has only in fact 8 power transistors?

See Answer In Context

dario_ramos_apc · ‎2021-06-29

Hi Hunter

Thanks for your answer but it doesn't help.
Fortunately I don't confuse a noisy inverter with a noisy blower.
The noise happens only without mains voltage present, when the inverter of UPS is converting batteries power to AC output.
It sounds like "hiccups". With this kind of sounding I suppose that there are some current protection actuating. Its why I would like to confirm the number of transistors.

dario_ramos_apc · ‎2021-06-29

Hi there

Nobody knows how many transistors has this UPS's inverter?
I would like to confirm if the inverter noise is related with an hypothetical wrong number of transistors in my UPS.

Message was edited by: dario_ramos

dario_ramos_apc · ‎2021-06-29

I have an 1500VA UPS that is noisy when running from batteries and with some kind of loads.
It is noisy with computer loads but not with linear loads like lamps.
The noise is not continuous.
From my technical experience it seems to be current pulse interruptions.
The UPS is not overloaded because this behaviour starts with 450 Watt computer load.
Based on this idea I compared the inverter of this SUA1500 with other of an old SU1400 that I have also.
In the SU1400 inverter I count 16 power transistors. In the SUA1500 inverter I count 8 power transistors.
Is there some one who can confirm that SUA1500 inverter has only in fact 8 power transistors?