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Need Schematic Help for Eltek power Supply

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DRBuck:
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K3SK
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I am in need of a schematic , or as a minimum the detailed  circuit layout for the cooling fan circuit in an Eltek Valere Flatpack2 48v3000w P/N 241119.905A HE. I am trying to eliminate RF noise created by the power supply's PWM circuit that controls the cooling fan.

I use these power supplies to power a couple solid-state KW amplifiers for ham radio.  When first keyed down there is no issue. After a short time as the power supply load increases and the cooling fan in the supply speeds up I start hearing a low frequency buzzing/pulsing on my transmitted signals.   I'm 99% sure the PWM circuit is my problem.   When unkeying and the PS fan slows down, the noise disappears. I've added half a dozen ferrite beads on the DC supply lines to the amplifier that reduced the noise somewhat, but receiving stations still report to me that there is noise. One guy even described it a sounding like a helicopter flying outside my window. This noise is identical on all of these Eltek 3000 watt power supplies I've tried.

trobbins:
Perhaps find an Eltek distributor who has a service department, as they are likely to have schematics, or can ask Eltek directly - at least for a schematic of section you are interested in as they may restrict circulation depending on how recent the model is.

DRBuck:

--- Quote from: trobbins on May 19, 2020, 07:11:31 am ---Perhaps find an Eltek distributor who has a service department, as they are likely to have schematics, or can ask Eltek directly - at least for a schematic of section you are interested in as they may restrict circulation depending on how recent the model is.

--- End quote ---

They claim proprietary and won't release me any info.

coromonadalix:
Thats sums it up,  if its propriettary  you wont get a schematic unless it was leaked on the web ... or reverse  engineered    :-\  or try  another time  with an signed non disclosure agreement ?

trobbins:
Have you thought about reverse engineering?  At least to get the fan model and see what PWM control it has and whether it has any design notes on noise/EMI reduction for speed control applications.

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