Arduino connecting relay has no power output
It sounds, from your textual description (please post a schematic or at least a photo of your setup) that you aren't providing power to the relay.

A relay doesn't have a power output.  It never provides power - it is merely a magnetically operated switch.  It is used to switch an external source of power on and off.

Treat the NO and COM pins as either side of a normal button or switch and wire it accordingly - that is (for example) connect COM to the positive of your power supply, NO to one side of your load, and the other side of your load to the negative of your power supply.

You can share the same power supply as you are feeding to the logic / drive side of the relays.