For controlling emission of particulates from thermal power plants, the vertical wires placed in between the grounded collector plates in an electrostatic precipitator are biased typically to voltages of
1
+ (100 V to 500 V)
2
+ (20 kV to 100 kV)
3
– (20 kV to 100 kV)
4
– (100 V to 500 V)