I am a bit of a newbie when it comes to electronics, the only reason I am here is because I need to make something work and cannot do so because of the lock down. So please, bear with me.

I have a portable fan. It needs a 36 Volt power supply. Due to the lock down, I am unable to order a 36 Volt power supply.

I have a 12 Volt and a 24 Volt power supply, my question is that can I connect them together to output a 36 Volt power supply?

I don't want to risk anything cause the fan is quite costly.

And if I can connect them together, how do I do it?

EDIT: Images of the power supply:

12 Volt Power Supply 24 Volt Power Supply

Sorry, they do not have much information on it. I come from a third world country and this is the kind of stuff you get in most of them. :(

  • 5
    \$\begingroup\$ It depends. Only if at least one of them is isolated. Need more info on the supplies \$\endgroup\$
    – DKNguyen
    Apr 22 '20 at 13:53
  • \$\begingroup\$ We need more information on the power supplies. If you can take a photo of the markings on them that would be very useful. Datasheets for the supplies would be even better. \$\endgroup\$
    – Jack B
    Apr 22 '20 at 13:58
  • 2
    \$\begingroup\$ Odds look good so far Do you have a multimeter? Use resistance test. Make sure no input terminal is connected to any output terminal. \$\endgroup\$
    – DKNguyen
    Apr 22 '20 at 14:38
  • 1
    \$\begingroup\$ Set meter to resistance. Put one probe on an input pin and the other probe on an output pin. It needs to read infinite or OL (overload). Zero means zero Ohms which means not isolated. Do all combinations of input with output pins. \$\endgroup\$
    – DKNguyen
    Apr 22 '20 at 14:53
  • 1
    \$\begingroup\$ Especially make sure neither DC(-) is connected to case ground \$\endgroup\$
    – Kyle B
    Apr 22 '20 at 15:24

With the supplies unplugged from the mains, measure the resistance between the mains pins (live, nuetral, earth), and the output, if both of them have a near short between earth and the output ground your out of luck, if 1 or none have a connector to the output, you should be fine.

If paranoid, you can test it by having them both powered, and measuring the voltage across the 2 supplies, e.g. supply 1 ground to supply 2 +, if they are isolated they should drift towards 0V within a small amount of time, do the same from supply 1 + to supply 2 ground, if its about the same voltage it reduces to, you can be fairly certain they are isolated and safe to connect in series.


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