I had a power supply blow and I replaced it with one from the same company with the same model number. The new supply has lightly different specification than the old supply. Oddly (to me) it gives the voltage as a range.

Old Supply: U in: 120V 60hz (AC) P in: 600W U out: 18 V (DC)

New supply: U in: 120V 60hz (AC) P in: 600W U out: 12-24 V (DC)

Same company, same model number, but it has a voltage range... I get that you can have dual output supplies but that is typically written 12/24 volt, come with an amp rating at each voltage, and have some clear way of hooking up either 12 or 24 V. So my questions are

  1. How does it work for a power supply to output a range? I wouldn't think that possible.
  2. If it is outputting 24 v is that going to damage an 18v DC motor?

Edit: This is a Linak power supply for a standing desk powering 3 Linak legs/actuators. The old supply had a button control pad that connected via an RJ45 cable - it also had a mysterious unused small molex port on the board near the RJ45 port. The control pad for the new supply has a small digital LED screen on the button pad to display height and it has a small cable plugged into that port. There is a small secondary transformer on the secondary "fuse board" for stepping 120V to 11V and powering that LED. The tags on the torroidal transformer for the two units are identical output voltages (31 V). So, the 12 V is for the LED output, the 24 V.... still not sure why it says that. Both Boards have a pair of 2200uF 63V caps that appear to be in parallel dumping 21 V into 3 sets of 4 mosfets (1 set for each leg). Consumption by the board probably drops it down to 18V by the time it hits the legs.

  • \$\begingroup\$ Does it have a potentiometer on it somewhere that changes the output voltage when you turn it? \$\endgroup\$
    – Hearth
    Mar 22, 2020 at 1:02
  • \$\begingroup\$ no external switches. I am going to open it back up and see if there is anything like that in there. The guts after the AC in and the fuse are a little different, I need to inspect them more closely. \$\endgroup\$
    – TBP
    Mar 22, 2020 at 1:03
  • \$\begingroup\$ It must somehow be adjustable. I have seen some where there was a VERY non-obvious little hole and a screw recessed below the hole that could be turned to adjust the voltage output. But I would measure the output voltage first to see if it is already set to 18V. \$\endgroup\$
    – user57037
    Mar 22, 2020 at 1:08
  • 1
    \$\begingroup\$ @TBP - Hi, (a) What is this a power supply for, and is that load (whatever it is) supplied by the same manufacturer as the power supply itself? (I'm asking because if the PSU manufacturer knows the load, then they have extra knowledge about what supply voltage range that load can accept.) Are LED lights involved here? (b) Can you edit the question and add a photo of the ratings markings for the new PSU, and, for comparison, the old PSU too if possible? Perhaps there are some other clues in those markings, which are not obvious in the text given so far. Thanks. \$\endgroup\$
    – SamGibson
    Mar 22, 2020 at 1:15
  • \$\begingroup\$ So I take it everyone is up for a good mystery while they shelter in place? Give me a few minutes. \$\endgroup\$
    – TBP
    Mar 22, 2020 at 1:31

1 Answer 1

  1. It's either two models: one for 12V the other for 24V but they have the same model number, you just have to add 12V or 24V when you order them. Manufacturers are too lazy to write different model numbers. Or it's an adjustable supply from 12 to 24V. And you can regulate it to 18V. But usualy the adjustable range is narrower than that.

  2. I don't know if it will damage it but the motor will be much stronger, (stronger torque). Maybe too strong. Will certainly overheat and smoke. So it's strongly recommended not to use 24V instead of 18V. 20V may be OK.

  • \$\begingroup\$ Yes, my next step will be to get out the multimeter. \$\endgroup\$
    – TBP
    Mar 22, 2020 at 1:45

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