always at unity power factor

at its own power factor

at a power factor below a particular value

at a power factor depending on the power factor of the load

common core flux

leakage flux

size of the core

permeability of the core material

50% to 70%

60% to 75%

80% to 90%

90% to 98%

increasing the thickness of the laminations

decreasing the thickness of the laminations

winding the coils with a higher gauge wire

decreasing the air-gap in the magnetic circuit

without changing its power

without changing its frequency

without changing its shape

without changing its power, frequency and shape