Air forced cooling system

At higher current ratings (i.e. over 25 kA), in order to maintain temperature rise values within requested and specified limits, it may be necessary to force cool the IPB. This practice reduces the physical size of the IPB to overcome possible space limitations.

A forced aircooling system is used to achieve these objectives. Generally this unit consists of an air-water heat exchanger, two fans, one of which is on standby. Automatic devices should be included to give alarm signals in case of inadequate functioning of any part of the system.

The air blown into two phases is drawn into the third, cooled when passing through the heat exchanger and returned to the circuit (closed system). To remove the possibility of arc transfer, grounded deionizing grids are built into the ducting used to transfer the air from phase to phase. However, the exact system for a particular IPB installation will depend on the general arrangement and specifications.