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Harmonic in UPS (The contactors shake)

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azadfalah

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

20171006_044501.jpg

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?
 

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

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

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.
 
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
 

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 ...
 
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.
 

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...
 

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