UPS high voltage output

[malik_zohaib]

hi guys my ups is giving very high voltage about 290v with no load and 260-270v with load, i lost many mobile adapters due to this:sad:. how can i set the voltage to 230v???is there any problem in transformer???

 

[MAXPAYNE]

I think there is a problem in relay or relay driving transistor, which is used for AVR (automatic voltage regulator) in an UPS.

 

[malik_zohaib]

can you explain this? how can relay control the voltage or regulate it????

 

[MAXPAYNE]

In a UPS AVR, there are several tapping in the secondary. these tapped point voltage connects in phase with the primary and acts as an auto-transformer i.e. total output voltage is greater than input voltage. if secondary is out of phase with primary total output voltage reduces. relay is used for changing tha tapped connection. this way voltage is regulated in an UPS.

 

[malik_zohaib]

this mechanism is used in stabilizer not in ups!!!. triangular and sine waves are used to generate the appropriate pwm in ups.

 

[MAXPAYNE]

in iron core transformer based UPS, this mechanism is used !

 

[masterleous]

can you explain this? how can relay control the voltage or regulate it????

Is this a first time that you had checked the output voltage of this UPS? or had checked before? I think you are using a locally made UPS. If YES than don't worry, its normal. The voltage goes lower and so on upon increasing LOAD.

 

[murali_dece]

first you wright down all the ic numbers in your ups and search for data sheets to find pulse width modulator used in your UPS. by modifying feedback loop/network you can reduce output voltage slightly.

 

[tpetar]

Voltage in UPS is regulated over transformators windings. You should check control circuit.


Example of voltage correction device, not UPS but principe of voltage regulation :



220V 210V 200V 190V 180V

Each relay is connected with adequate transformator windigs.

 

[malik_zohaib]

Is this a first time that you had checked the output voltage of this UPS? or had checked before? I think you are using a locally made UPS. If YES than don't worry, its normal. The voltage goes lower and so on upon increasing LOAD.

yes its locally made and i checked it before. but now its damaging appliances like fan, mobile charger, and adopters.

 

[tpetar]

Localy made or not this is wrong situation, and you will continue destroying your devices. UPS must have appropriate voltage on output 220V/110V. Maybe this is bad design or some "expert" made that, or have some failed parts inside.

 

[malik_zohaib]

Localy made or not this is wrong situation, and you will continue destroying your devices. UPS must have appropriate voltage on output 220V/110V. Maybe this is bad design or some "expert" made that, or have some failed parts inside.

so what i do? how do i locate the faults?

 

[tpetar]

Tell us whole story? Is this from begining? Did ever ups running ok with voltage before ?

---------- Post added at 13:45 ---------- Previous post was at 13:45 ----------

Send pictures of device and circuit if you have.

 

[malik_zohaib]

it was working fine before. during thunder night it just stop working (static charge i guess!!) and when i checked the main board the relay (they called it soft starter!!!) is damaged. i had to take it to my supplier, and he replaced the relay. since then its not working properly.

 

[mtwieg]

Without knowing the operating principle of the UPS it's hard to say. Is it a PWM inverter, multilevel converter, simple square wave inverter, etc...

 

[tpetar]

Yes this is relay. This is small power ups, for what you using this?

What he change of this parts ? Did you return board to service again ?

 

[malik_zohaib]

i dont know its purpose. he just changed the relay. i am using the same board.

 

[tpetar]

Where you using this ups to power what devices ?

 

[malik_zohaib]

i am using to power fan, energy saver, mobile charger etc. also let me tell you one thing more: my ups is 1200VA, and its just the main board; the inverter is fitted into the casing.

 

[tpetar]

Best is to send this to manufacturer service. Its hard to tell anything from this, except if we have Baba Vanga capabilities.