Subsea power supply assembly supplying electric power to a motor at a second location from a first location. The subseas power supply assembly includes a variable speed drive (VSD) and a step-up transformer connected to it. At a subsea location the assembly includes a first step-down transformer with input and output and an uninterruptible power supply having an input. A step-out cable supplies power from the step-up transformer to the motor. The cable connects to the first step-down transformer. The speed of the electric motor is proportional to the output frequency of the VSD. The power receiving input of the uninterruptible power supply connects to the output of the first stepdown transformer, thereby receiving electrical power with frequency equal to the output frequency of the VSD.