Hypersensing questions

Is there a preference or a link for a suitable 24v isolated power supply? I see in the docs HDR-15-24 but I cant find availability.

snowgoer540 wrote:

bevins wrote:

Is there a preference or a link for a suitable 24v isolated power supply?

From the Plasma Primer:

We used a 15W Mean Well HDR-15 Ultra Slim DIN Rail Supply 24V DIN rail based isolated power supply.. This is a double insulated Isolation Class II device that will withstand any arc voltage that might be applied to the terminals.

Here's a link to one in the states (no idea where you are):
www.amazon.com/Meanwell-HDR-15-24-Power-...l%2Caps%2C202&sr=8-6

I didn't understand the importance of using a double insulated class 2 power supply at first. It can not have a path to ground, it must be floating.

Yeah, thanks, I ordere a meanwell also.


Rodw, will a 1/2watt 24K resistor on the ohmic schematic instead of 5 watt do from the that pulls down the 24v and connects to the -IN on thcad?

I cannot find the 24K 5 watt anywhere. mouser, didgikey, amazon, not in stock anywhere....

20K to 30K should work about the same (approximately 1ma sense current)

25K or 22K are much more common than 24K

5W is important in case of accidental short of the probe to the plasma voltage
(a 1/2W 200V max resistor might explode)

BTW Digikey does have a 24K 5W resistor:

www.digikey.com/en/products/detail/te-co.../ROX5SSJ24K/10231946

bevins wrote:

Is there a preference or a link for a suitable 24v isolated power supply? I see in the docs HDR-15-24 but I cant find availability.

Yeh thats the one. Authoritave link here www.meanwell-web.com/en-gb/ac-dc-ultra-s...dr-15-24%23hdr-15-24

But when I looked it was readily available in all markets. I use RS Components and Element14 (Farnells) who both list it.

I ended up using 5 x 4.7k 1 W resistors in series (23.5k 5 W total) becasue I could buy them locally.

There is nothing accidental, the torch voltage shows up as a full scale reading of the THCAD whenever its cutting. Thats why we use the HDR-15-24 with the THCAD as both are rated to 500 volts.

Yeah I got them coming. Thanks
At fiurst gl;ance they wre Out of stock wherever I looked.

rodw wrote:

bevins wrote:

Is there a preference or a link for a suitable 24v isolated power supply? I see in the docs HDR-15-24 but I cant find availability.

Yeh thats the one. Authoritave link here www.meanwell-web.com/en-gb/ac-dc-ultra-s...dr-15-24%23hdr-15-24

But when I looked it was readily available in all markets. I use RS Components and Element14 (Farnells) who both list it.

I ended up using 5 x 4.7k 1 W resistors in series (23.5k 5 W total) becasue I could buy them locally.

There is nothing accidental, the torch voltage shows up as a full scale reading of the THCAD whenever its cutting. Thats why we use the HDR-15-24 with the THCAD as both are rated to 500 volts.

I ordered the DR-15-24 same except not thin line. Still class II isolation and power supply.

I am goi8ng to test it with the float switch as the probe then try the ohmic3 sensor version.

bevins wrote:

I ordered the DR-15-24 same except not thin line. Still class II isolation and power supply.

Interesting. Aside from availability, I wanted to know what you got for the extra $. I had a look at the specs. the DR-15-24 has less output derating once the ambient temp goes above 50 deg C. That was about all I cold see.


Plasmac supports both ohmic sensing and float switch input at the same time so I would do both right at the beginning.