Dummy Lab PSU questions

[aluck]

I have a single-output lab PSU with three terminals on the output - plus, minus and ground. The ground is wired internally to ground pin on the wall outlet. Plus and minus are floating.

1. What's the point of having ground terminal? Can you think of some reasonable usage?

2. If I would get another one single-output lab PSU (also floating output), could I just wire (+) of one PSU to (-) of the other, call it the "ground" for my project, and use them for supplying both positive and negative voltage?

[IanB]

This other thread probably answers your questions:

https://www.eevblog.com/forum/beginners/what's-the-'ground'-terminal-for-on-all-these-dc-power-supplies/

[aluck]

This other thread probably answers your questions:

https://www.eevblog.com/forum/beginners/what's-the-'ground'-terminal-for-on-all-these-dc-power-supplies/

Thanks.

But the second question still remains.

[alm]

Yes, that's the whole point of floating power supplies. Either connect the center terminal to the ground terminal on one of the supplies, or call it something like 'circuit ground' to distinguish it from physical earth. You can just connect them like batteries in series or parallel (within limits, don't go crazy and connect them to high voltage supplies).

[aluck]

Yes, that's the whole point of floating power supplies. Either connect the center terminal to the ground terminal on one of the supplies, or call it something like 'circuit ground' to distinguish it from physical earth. You can just connect them like batteries in series or parallel (within limits, don't go crazy and connect them to high voltage supplies).

Thanks a lot.

[saturation]

When connecting 2 or more floating PSU in parallel, say for more current, be careful to match the output voltage as near exact for all paralleled supplies.  All paralleled supplies sense and will adjust to regulate the voltage output.  If they have unequal output voltage or even regulation specs, the better supply will compensate for the lesser supply.  In high current usage, it could overheat the better supply.  You could say all specs of the better supply will be reduced somewhere between its specs and the lesser supply's specs: regulation and recovery time, ripple etc.,