Harmonic in UPS (The contactors shake)

[azadfalah]

Hello friends
I designed an inverter 24 to 220 volts
You can see the output waveform in the image below.



output : 50hz 230v RMS (Measured with tools Ture RMS)

The problem is that when the two contactors are activated, the contactors start Shakes so badly
How to solve this problem?

 

[andre_luis]

No schematics, no contactor specifications, no idea from what this waveform refers to.

 

[nikhilmahasvar]

The contactors are useed for what purpose exactly ? And what is the purpose of this inverter ?

 

[schmitt trigger]

This is the "classic" waveform of a push-pull-converter with an iron core transformer without a reset winding.
I know....I built several just like that in the late 1970s utilizing a 3525.

No simple solution to clamp the narrower spike. There is a lot of energy in an iron core magnetizing inductance.

And I am sure that your transformer is also overheating.

My advice: Go for the high frequency, "modified sinewave" route.

 

[azadfalah]

This is the "classic" waveform of a push-pull-converter with an iron core transformer without a reset winding.
I know....I built several just like that in the late 1970s utilizing a 3525.

No simple solution to clamp the narrower spike. There is a lot of energy in an iron core magnetizing inductance.

And I am sure that your transformer is also overheating.

My advice: Go for the high frequency, "modified sinewave" route.

Wow It was amazing .
I have to use this method for some reason ...
I realized I add a bunch of wires to the transformer and when push pull is Low short circuit (<1R) the bunch of wires to clamp the narrower spike

 

[Easy peasy]

The contactor shakes because you are not supplying an AC waveform with a low impedance, when the switches of your inverter turn off the current in the contactors drops to zero quickly and they start to release, if you put a 200W light bulb across the inverter output - this will help as it lowers the impedance of the AC supply - less shaking in your contactors ...

 

[azadfalah]

The contactor shakes because you are not supplying an AC waveform with a low impedance, when the switches of your inverter turn off the current in the contactors drops to zero quickly and they start to release, if you put a 200W light bulb across the inverter output - this will help as it lowers the impedance of the AC supply - less shaking in your contactors ...

Yes thanks, we tried it and got better, but the same hardware with the same amount of pulse width did not have this problem.

 

[Easy peasy]

exactly the same hard ware and no load? it seems doubtful - study phase shift full bridge - this is a better way to drive the Tx and get a low impedance drive to your loads...