Monitoring upper speed limit of asynchronous machine, using twin processor system that allows upper limit to be monitored in two separate ways and compared by cross-correlation

摘要

A method for secure speed monitoring involves using a system with two processors (1,2) that compares results in a cross-correlation manner. Accordingly both processors are joined together via a communications device so that both processors can implement speed monitoring in a different manner. The second processor determines a current is-value or the actual output frequency of the transformer and triggers a limiting value monitoring by the first processor if it detects that the limiting value has been exceeded. An independent claim is made for a twin processor speed monitoring system for use in monitoring the upper speed of a machine.