K40 power supply upgrade to Cloudray 100W

Could someone please help me figure out how to properly and safely connect the new power supply?

Have you seen this from @donkjr? He has a lot of useful info on his blog, and it’s fairly heavily interlinked.

From that, here are labels for the LPS connections on the old LPS:

You probably already know, but you need to also have a separate low-voltage power supply for the controller board; the Cloudray doesn’t supply both.

TH Input Signal On-Off laser control,TH≥3V, emitting laser; TL≤0.3V, no laser.
TL Input Signal On-Off laser control,TH≥3V, no laser; TL≤0.3V, emitting laser
WP Input Signal On-Off laser control,TH≥3V, no laser; TL≤0.3V, emitting laser
G GND This foot must be connected well with the laser machine shell and the ground of control board.
IN Input Signal The control of laser power: Both 0-5V analog signal and 5V PWM signal can control the laser power.
5V Output Power Output 5V, the maximum output current is 20mA.

Note: WP = water protection, this is an interlock loop for the water pump.

Looks like TH = H, TL = L, and WP = P for the labels on your supply, but otherwise the same as what he describes as a type B LPS.

There’s lots more there on his blog! Definitely check it out.



This drawing is not for the exact supply your using but the connections are typical for this style control.

The white wire on the back:
You may have a white wire on the back of the supply. It is usually intended to be connected to the cathode of your laser tube and is grounded internally. If you have a panel ammeter that would be in series with this circuit.

Looks like this supply has a built-in ammeter so this white wire may need to connect to the cathode circuit directly, I don’t know if also having a panel meter in series would be a problem.
There are no installation instructions on the cloudray site regarding this wire.
You could contact support and ask how the white wire should be connected.