fixed TDK Lambda rws600B 24v psu blew up when adjusting voltage

[amateur_24]

So I am building myself a cnc milling machine. I need 48v for the spindle but the psu only offers 24v.
I thought the cnc machine probably would only use a couple of amps at most. Therefore I tried adjusting the output voltage to see if i could get 48v out of it. However it just suddenly cut out whilest i was adjusting the pot at the back.

After leaving off for a bit, it now turns back on. I'm guessing I must of tripped the overvoltage protection. May I add it's not very effective as I was able to adjust the ouput up to 28v. Any 24v electronics connected to it would be toast.

 

[JimB]

Therefore I tried adjusting the output voltage to see if i could get 48v out of it. However it just suddenly cut out whilest i was adjusting the pot at the back.

Did you check the datasheet?

https://www.emea.lambda.tdk.com/uk/KB/RWS-B-Datasheet.pdf

It is unreasonable to expect such a PSU to give out twice the rated voltage.

After leaving off for a bit, it now turns back on. I'm guessing I must of tripped the overvoltage protection.

Correct.

May I add it's not very effective as I was able to adjust the ouput up to 28v.

Look at the datasheet, the voltage adjustment range is 21.6 to 27.6 volts, so the overvolt trip operating at 28v is reasonable.

Any 24v electronics connected to it would be toast.

Most unlikely.

And you expected to adjust the output to 48 volts ?
That seems an unrealistic expectation.
Where would the manufacturer set the overvolt trip on a PSU adjustable from 24 to 48 volts ?

JimB

 

[amateur_24]

true. I just didn't want to spend more money on a 48v psu. At least now I know my expensive psu is actually pretty well designed. As expected for such an expensive psu.

Any 24v electronics connected to it would be toast.

Most unlikely.

Really thats 4volts over. I am suprised by this.

 

[Nigel Goodwin]

true. I just didn't want to spend more money on a 48v psu. At least now I know my expensive psu is actually pretty well designed. As expected for such an expensive psu.

Most unlikely.

Really thats 4volts over. I am suprised by this.

Why?, most electronics isn't terribly voltage sensitive - exceptions tend to be specific IC's, such as TTL (usually 5V), or various CPU's etc. (often 3.3V or 5V) - but even then the circuit they are in 'probably' contains a voltage regulator to feed them.

While feeding 28V to a 24V circuit 'could' potentially damage it, I would imagine the chances would be relatively low.

I suppose a 24V circuit could use a 25V electrolytic across it's incoming supply, and that extra 4V 'could' damage it, modern electrolytics aren't very happy with over-voltage - but I'd like to think the electrolytic would be 35V, not 25V (that's a bit too close to 24V), so it probably wouldn't be an issue.

 

[rjenkinsgb]

Most 24V industrial gear is rated for somewhere from 28 - 30V maximum, or sometimes even more.