Vibration calibrator constant up to a maximum specified weight of test object. Older models can be used to calibrate objects weighing up to a maximum of approximately 100 g, whereas the latest instruments can work stably with test objects weighing over 500 g. Vibration calibrators are most often used for testing and checking vibration sensors and measuring instruments at the site of their operation and are, therefore, usually transportable and battery operated. The most commonly occurring vibration frequency of calibrators is 159.2 Hz, which is equivalent to a radian frequency of 1000 rad/s. The vibration displacement, velocity and acceleration of sinusoidal signals
Per-unit system use the nominal voltage 138 kV as the base voltage formula_23. We then have: If, for example, the actual voltage at one of the buses is measured to be 136 kV, we have: The following tabulation of per-unit system formulas is adapted from Beeman's "Industrial Power Systems Handbook". It can be shown that voltages, currents, and impedances in a per-unit system will have the same values whether they are referred to primary or secondary of a transformer. For instance, for voltage, we can prove that the per unit voltages of two sides of the transformer, side 1 and side 2,