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Electronics => Beginners => Topic started by: Asterix on September 07, 2020, 08:51:54 pm

Title: Condensator power factor
Post by: Asterix on September 07, 2020, 08:51:54 pm

Hello,

I have this magnetron wich keeps causing trouble.
To be exact. the circuit trips on it.
It is a pelgrim mag555rvs/p04.

I have replaced the magnetron-unit(Radiating unit)
and trafo. Wich i know now are good.
However the circuit keeps getting faulty.
I have measured:
-Diodes are okay
-Trafo is okay(Primary and secondary)
-Microwave-unit. Wasnt good but replaced it.
-Rotating motor. is okay
- Fans they spin freely and the motor's have good resistance.
-High voltage Capacitor. is okay. meets the exact value as indicated.

So what keeps happening is that u are able to plug in the unit. set time but the moment u put it into microwave on the buttons. it starts and than. it gives a short.
It appears to be a neutral to earth sort. But not shure yet.
Now i diagnosed it again and found a wire pressed between the chassis and the buttons. i have fixed this so i will try the machine once more tomorrow morning.
I also found that there is a AC capacitor soldered between Line and Neutral on the power board. i measured this and it shows 0.73nanoFarad while it is supposed to be 220 microfarad.
so that one has to be replaced i think. I am an electrician as my job. so i know a bit of condensators and i know it must compensate the inductive load. But is this bad capacitor enough to cause a 16 ampere fuse to shut it of? or do i need to look a bit further.
Does anyone have some experience with this? and can u tell me a bit more?
Or maybe where i need to look? cause i am starting to run out...

Regards,

Title: Re: Condensator power factor
Post by: srb1954 on September 07, 2020, 09:17:12 pm

Are you sure the capacitor between line and neutral is supposed to be 220 microfarad?

A capacitor this big would draw an awful lot of current from the mains, far more than what is necessary to compensate for the power factor of a typical microwave transformer.

More likely it is an interference suppression capacitor and a value of 220 nanofarad would be more appropriate.

Title: Re: Condensator power factor
Post by: Asterix on September 08, 2020, 02:44:55 am

Hi

I was shure i read 220uF on it.
I would check tomorrow morning if it is between Line and Neutral.
I forgot to mention however it is a combi so both microwave and grill.
Do you happen to know what could be the fault for the circuit tripping?

Regards