balancer set

1 :  two or more similar direct-current machines directly coupled together and connected in series across the outer conductors of a multiple-wire system of distribution for the purpose of maintaining the potentials of the intermediate wires of the system, which are connected to the junction points between the machines —called also compensator, equalizer set

2 :  reactors or transformers with their wires so interconnected as to equalize the voltages between the wires of a multiple-wire alternating-current system —called also static balancer