# Terminals of three phase power machine

A three phase machine, instead of having six terminals, two for each slip ring, has only four terminals. Because the starting point of all the three coils have a common junction which is usually earthed and the other three coils are connected to three separate terminals on the machine.

What does the starting point mean here? And how do we have 4 terminals when we are having six slip rings. Terminal from each slip ring would make it 6 terminals.

The machine is wired to have 3 winding at $120^o$ spacings, physically. If they are all driven by the right phase with the current flowing in the consistent pattern then the machine will operate correctly. This access to both sides of the windings allow you to wire up the machine to be Delta, Wye, reverse direction Delta, reverse direction Wye.