Duplex Alternator MPE Alternating Relays are designed to perform automatic alternation motors or other types of loads, and are available in 120 VAC. The Alternator causes the loads to have even run times. The output relay contacts of the Alternating Sequence Relay change state each time the control switch is opened. Many wiring options are available for these Duplex Alternators as well as these hardware options for the Sequencer: (1) A lead/lag/automatic selector switch and (2) A push-to-test switch for added convenience or trouble shooting.