The Planck-Balance is a compact version of a Kibble balance, allowing a direct measurement of mass by means of electromagnetic force compensation (EMFC). This means that the effects of deformation have to be considered. The vertical position adjustment of the coil, which is discussed in this article, can reduce many errors, such as errors due to deformations during weighing, which lead to a non-proportional correlation between the current in the compensation coil and the compensated mass. In our setup, these errors can be up to about 8 ppm in the maximum case. In addition, there are other problems such as higher order harmonics in the velocity mode, which can be reduced.

The Planck-Balance 1 (PB1) is a compact Kibble balance with the aim to calibrate weights of high quality. In contrast to most other Kibble balances PB1 employs a sinusoidal trajectory in the velocity mode, rather than a linear one. Thus, the induced voltage is an AC signal of 4 Hz. At PTB we implemented a commercial AC Quantum Voltmeter in order to ensure traceability to highest level. Here, we show the working principle along with some preliminary results.