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A transcutaneous energy transmission system is described that transmits up to 60 W for use by a mechanical circulatory support system or other internal device. It contains an input power conditioning circuit that permits it to sustain the required output with input voltages ranging from 10 to 16 V. The transcutaneous energy transmission system demonstrated a best overall efficiency of 77% when connected to a resistive load and 74% when connected to a mechanical circulatory support system pumping up to 8.0 L/min to a mock circulation system. These figures included the losses in the conditioning circuit, which, when operated separately, had an efficiency of 94%. By tuning the resonant frequency of the primary, an output with only a 10% variation was achieved with coils separated by between 0 and 25 mm. A model of the inductively coupled resonant circuits was analyzed and a closed form solution obtained that verified the equations reported by Galbraith et al. Additional useful results obtained included an expression for the efficiency of the power transfer through the coupled circuits and the ratio of the current circulating in the primary and secondary coils. These results indicate that information useful for control of the output voltage of the secondary may be available in the primary circuit.