A phase coil inverter was a piece of technology associated with sub-impulse thrusters. In 2370, Kira Nerys needed help in getting an old Bajoran raider to work again.Benjamin Sisko then asked Jadzia Dax whether any of her previous hosts had experience with such systems. Dax replied that Tobin Dax had who had been an expert in phase coil inverters. (DS9: "The Siege") Cardassian phase coil inverters utilized neodymium power cells. Jake Sisko and Nog needed such a power cell in 2373 to trade it to Elias Giger. (DS9: "In the Cards")