Products and services

Capacitor Banks


Damping reactor coil

The capacitor damping reactor coil supports quite a high nominal inrush current to cover all known capacitor bank switches or bank sections. The system planner must submit information on the frequency of the relevant inrush resonance to the reactor coil manufacturer. The reactor coil manufacturer provides the overvoltage factor (reactance/resistance ratio) for the damping reactor coil at this frequency.

SA, SB and SC series damping reactor coil. These non-iron (air core) damping reactor coils are used to absorb transients and inrush currents.

In series with the capacitor, the reactor coil reduces the inrush surge in the capacitor at a value that does not fatigue the insulation or damage the internal connections of the capacitor’s parts. Such a reactor coil remains connected following capacitor excitation.

As a result, it must be designed around the continuous load current to which the capacitor is exposed. Unless otherwise indicated, reactor coils are designed for a current overload of 43% and a failure level 25 times the rated current.


Single phase dry reactor coil with air core (non-magnetic core)

Rated Voltage

3.6 kV up to 36 kV

Rated Frequency

50 Hz or 60 Hz

Rated Current

Up to 650 A


Up to 1000 μH

Rated Insulation Level

3.6/10/40 kV up to 36/70/170 kV

Rated Short-circuit Current

43 x ln A/1 sec (25 x ln A/3 sec) up to 16 kA/1 sec

Dynamic Current

2.5 x lth


Cast resin (the reactor coil is encapsulated within an epoxy resin)

Coil Material


Easy Mounting

Internal or external

Temperature Class


Temperature Range

-40ºC to +70ºC


Natural air

Surface Protection

Against ultraviolet rays and class IV pollution areas

Safety Standards

CEI 60289