The design of the new NIST-4 watt balance

The design of the new permanent-magnet driven watt balance and novel mechanical features will demonstrate the high-precision capabilities of a new watt balance mass measurement system. This article will introduce the concept of replacing the counter mass with an auxiliary mass and precision alignment of the coil using a large flexure. The system is expected to have overall uncertainties on the order of 3 parts in 10
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