Sample and hold-circuit arrangement for an electrical motor simulator of an electronic motor protection relay

摘要

A sample and hold-circuit arrangement for an electrical motor simulator of an electronic motor protection relay wherein the motor simulator is charged by a charging current source with clocked charging currents through a main or primary switch controlled by clock signals. A sample and hold-amplifier containing a storage capacitor and an electronic switching device are connected through the main switch at the motor simulator and the electronic switching device is controlled by the clock signals. The sample and hold-amplifier containing the storage capacitor is electrically connected during the charging cycles to the motor simulator for recharging of the storage capacitor to the charging voltage of the motor simulator and during the rest cycles is electrically disconnected from the motor simulator for the control or triggering of the sample and hold-amplifier by the charging voltage of the recharged storage capacitor.