Providing power to a downhole-type tool includes positioning a downhole-type electric motor in a wellbore, electrically connecting a variable speed drive to the electric motor with three-phase conductors extending between the variable speed drive and the electric motor, where the variable speed drive controls and supplies power to the electric motor through the three-phase conductors, diverting at least a portion of a power supply from the three-phase conductors to a rectifier, and supplying, from the rectifier, the diverted portion of the power supply to at least one downhole-type tool proximate to the electric motor, the at least one downhole-type tool operable using the diverted portion of the power supply.