My DC power source is fluctuating as below it does not stay at fixed voltage. If i am trying to change to other value it does not reach evenly, why this is happening? does it damage the components?

 

Does it still do that when you disconnect the red and yellow wires? We don't know what is connected to those wires, they could be floating in some RF field...

 

The "zip"does not unzip. SO the TS will need to provide some actual words describing the complaint. How do they know it is really fluctuation?? AND, what sort of DC supply??

 

The "zip"does not unzip. SO the TS will need to provide some actual words describing the complaint. How do they know it is really fluctuation?? AND, what sort of DC supply??

It downloads as a .ZIP file OK?

 

I downloaded the zip and unzipped it. Strange behavior in that under no load, I see the current as zero but the Vout is bouncing around +/- several tenths of a volt around 38 ~ 39 volts. Since it's not driving a load and the Vout is open circuit my best guess is that the power supply itself is faulty. Less a good schematic to work from and good diagnostics tools like a good DMM and a scope I have no clue how to approach troubleshooting.

If you give it a load does it continue to not regulate? Also, I am correct as to no load, correct?

Ron

 

I may need a small load to stabilize.

 

There are some energy conserving schemes that will vary a bit with no load. But thy are not at all common. So certainly we need at least a description of "the DC source."

 

Many people here will not open a ZIP archive from an unknown source. Please post the individual files, of links.

ak

 

WE have no problem with larger posts
My anti-malware program has issues with zipped files.
So please unzip the file.

 

Thanks for the inputs, i have uploaded the video in the below path PSvideo, the power supply specifications i have attached, i am unable to set a particular voltage for example 40V, it goes to 37,38,36 and i can't set any voltage correctly under no load conditions, i have purchased this one year back, i am finding this issue recently, it is holding the set voltage when testing under the load conditions. No RF is connected I have been using the Power supply for testing the inverter to run BLDC motor. (To open the video we have to download using the 3 dots option at the right corner)

 

OK, a 23 amp 40 volt regulated power supply is quite something.
With that output current capability it undoubtedly is set up for remote sensing of the load voltage. Often times any noise picked up by the remote sense wires can cause output instability problems. I have solved a few problems with big supplies by repairing the load voltage sensing connections, and so I suggest that investigating the load voltage sense portion of the supply connections is a good place to start checking. With some brands of large power supplies, the voltage sensing connections are a bit complicated.

 

The original video as posted shows what I am guessing to be sense terminals clearly tied with jumpers to the power supply output. I did like this suggestion:

I may need a small load to stabilize.

I tried to upload the unzipped MP4 video which gives me:

The uploaded file does not have an allowed extension. The following extensions are allowed: .7z, .asc, .asm, .stl, .asy, .c, .cir, .csv, .djvu, .doc, .docx, .epub, .fzz, .gif, .hex, .inc, .ino, .jpe, .jpeg, .jpg, .lbr, .lib, .ods, .odt, .pdf, .png, .py, .rar, .sch, .s

Ron

 

There may still be an issue with the sense arrangement. "Big" power supplies often require reading and understanding the technical manual that comes with them .
Does the TS have any information about the power supply?? Is the TS willing and able to provide us with the supply brand and model information??

 

Saw 38.7V to 39.2V, a total change of half a volt. At 39V that's not a big fluctuation. Do you need a steady 39V? 0.3V below to 0.2V above doesn't seem like much of a problem. Perhaps some pictures of what you're doing. The lack of clarity on the other meter doesn't help.

One thought as to why you're fluctuating could be a dirty coarse or fine adjustment pot. However, that usually manifests when adjusting the knobs. Still, it COULD be dirty pots. Since the current meter shows no current draw one would have to assume there is no load. Still, looking at the knobs for the current - one knob appears to be fully counter clockwise (CCW) and the other appears to be fully CW. We (I, myself) don't know if that's a part of the problem.

More pictures please.

And yes, I opened the zip file. Shouldn't have.

 

The problem may possibly be a noisy voltage setting adjustment potentiometer. So my first repair suggestion is trying some electronic contact cleaner to see if that helps. I have repaired quite a few pieces of used electronic equipment that way.
Without knowing some of the details of the regulation scheme, providing useful advice is not likely to happen.

 

During the video I did notice the name on the power supply. Google brought up a few links.

https://www.indiamart.com/sairush-e...6bnEPyKOPbWS2N53T9jm0hu_qXXdbVbkvrVxRs60Bxlvv

Looks to be a linear but I am not about to play games with India Mart looking any further. From the video it appears the Vout and Sense are tied at the output terminals using jumpers across the banana jacks. If the thread starter can't provide the exact make and model I am done with this.

Ron

 

Sorry for the late response, it is not a big supplier i bought from local manufacturer.

i have now disconnected all the wires it is open load now. I have attached the video changing the voltage.

 

Over the years I have encountered incorrect operation of equipment caused by inadequate or even shaky connections. Those connections may, or not, be good connections, There may be a loose screw.. If a power supply has an unstable output voltage with no load, then additional investigation is in order.

 

Few concerns when changing the voltage to higher value, it goes to low value and keeps coming back, i am not sure why. The supplier is the same as mentioned earlier from Sairush electronics systems. Please let me know if any tests to be done to confirm if the power supply is fine.
Powersupply

There is also schematic shared during installation.

 

A reasonable test will be to connect a load resistance of about 100 ohms, which will draw a load current of about half an amp. That will allow observing light load stability. The higher current test should first be done at half output, but then at full output voltage.
Caution is needed because the resistor will become very hot. Those tests should show if the supply is adequately stable or not.

One additional thought is to observe if the AC mains supply is adequately stable. THAT might be part of a problem.