As I understand it, the Photon Point Defence Console can only be used on the Armitage with which it was purchased. However the Phaser Point Defence Console will work on any ship and is a Universal Console.
If used, it does not function with any torpedo power such as high yield or spread. It will simply fire volleys of torpedos at all targets within it's range of ~5km
Torpedos work by adding to your DPS, they provided kinetic damage and have the highest effect against an unshielded target. Generally speaking if a target has some shields a torpedo will do little damage to the target.
The exception to this is Transphasic Torpedos which do damage through shields; the other exception is plasma torpedos which burn the hull with the plasma fire.
Torpedos are not affected by your weapons power setting, they simply do damage. They will boost your cannon DPS due to the fact that you will have extra weapon power from not having slotted the extra turret or cannon, you will also be better able to utilise tactical ensign slots with torpedo powerups such as spread if you use them.
Torpedos have a shared cooldown, which means you shouldn't place more than two torpedos up front in order to maximise firing rate. If you are using the Projectile Weapon Officer Doffs, you should only use 1 or you waste the second torpedo slot.
They are not affected by range either if you fire them at your target they will do the same damage if they hit at any given range inside 10km.
Moving targets provide an issue to torpedos in that they disappear after a short period of time, firing a torpedo at range at a fast moving escort in PvP for example could cause your torpedos to fail to find their target at all.