
7.8. Reactors 93
7.8. Reactors
Reactors of all types are the brethren of transformers. Iron-core reac-
tors share the same characteristics as transformers as regards con-
struction, insulation, and temperature ratings. Air-core coils are a
more specialized class, often used in large sizes for outdoor harmonic
filters or fault limiting, and in smaller sizes for di/dt limiting in equip-
ment. Some general guidelines are shown in Table 7.3.
The basic equations for an inductive circuit section are shown in
Fig. 7.18. The voltage is the derivative of the flux linkages, λ, the
product of inductance and current. If the circuit inductance is con-
TABLE 7.3 Air