Hi, everyone. My UPS is not switching output from mains to the battery. I am not experienced so my questions for proffesionals could be strange , (sorry for that). Inside are only three relays, all three relays during startup switching the mains power. I couldnot find out how its switching to the battery energy after loss of mains. That i will try to find later on. I saw there 6 IGBT's (K25H1203)and 6 MOSFETS(70N20) , please help me undersrand why we need both. I thought only MOSFET's or IGBT's should be enough for inverter circuit. Thanks for any ideas.

 

Is the battery charged up?

If it's old and not holding a charge then the UPS won't work.

 

Is the battery charged up?

If it's old and not holding a charge then the UPS won't work.

Yes they are new, in good condition. I checked them on load. Have you any idea about MOSFET and IGBT's that i mention in thread ?

 

What model UPS is it?
Do you know if it is an online or offline version?

 

What model UPS is it?
Do you know if it is an online or offline version?

Sorry but i dont know the difference between them, i will check it. But does it matter for this case the type of UPS? What can give that to me if I know it?

What model UPS is it?
Do you know if it is an online or offline version?

I checked it, it looks like OFFLINE type.

 

With the offline type you have possibly two power sections:
1. Take power from the battery and generate output mains voltage.
2. Condition and regulate the AC mains input (while present) to produce clean regulated output voltage.

The MOSFETs and IGBTs will be doing those two things (probably MOSFETs doing the input conditioning).
Is this a three phase UPS? That might be why everything comes in threes.
Please tell us the model number.

 

With the offline type you have possibly two power sections:
1. Take power from the battery and generate output mains voltage.
2. Condition and regulate the AC mains input (while present) to produce clean regulated output voltage.

The MOSFETs and IGBTs will be doing those two things (probably MOSFETs doing the input conditioning).
Is this a three phase UPS? That might be why everything comes in threes.
Please tell us the model number.

No its one phase 220 VAC input and 220VAC OUTPUT, I will write the model as soon as possible.

With the offline type you have possibly two power sections:
1. Take power from the battery and generate output mains voltage.
2. Condition and regulate the AC mains input (while present) to produce clean regulated output voltage.

The MOSFETs and IGBTs will be doing those two things (probably MOSFETs doing the input conditioning).
Is this a three phase UPS? That might be why everything comes in threes.
Please tell us the model number.

I am trying to check the IGBT gate drive circuit, there are 3 separate boards with 3120 optocoupler. The output of 3120 is going to 10R resistor and after on smd transistor. Is it possible if one of 3 gate drive circuits not working to loss output completly?