What is the difference between loop terminal and line taps

Taps provide two or more voltages or are used to make adjustments to a nominal voltage to adapt to local line conditions.  All taps work by essentially changing the primary to secondary winding ratio which dictates the input to output voltage ratio.

Loop Taps:

The coil's conductor is bent into a loop on the outside of the conductor and used to mount the tap conductor.  This is a simple, cost effective method which doesn't involve heating the wire to braise a terminal pad.

Terminal Taps:

Sometimes referred to as lug taps, are created when a landing pad is braised onto a point in the coil to mount the tap conductor.  This must be done with foil windings or typically when three or more conducting wires form the winding.

Line Taps:

Most taps are on the line side and primary coil of the transformer.  This is typically the outer coil.