TSM-LC

Thyristor switching modules for dynamic PFC, TSM-LC series, 10 … 100 kvar · EPCOS AG / TDK Electronics

A conventional compensation panel switches its steps with contactors, and contactors have a fixed number of operations in them — between 100 000 and 200 000 over their whole life. On a press line, a spot welder, a crane or a lift, the reactive power demand changes on a millisecond scale and the switching count needed can reach 100 000 a year, which burns out both the contactor and the capacitor within a year or two. Worse, IEC 60831 allows a low-voltage capacitor only 5000 switching operations a year, so the capacitor gives up first. The TSM-LC series is the answer to that: an electronic switch in place of the mechanical one. Each module is a fast, self-monitoring thyristor switch for capacitive loads that connects a capacitor step within about 5 ms, with effectively no limit on the number of operations because there is nothing to wear. It holds the capacitor at the peak value of the grid voltage and connects it only when the grid reaches that same peak, so the step is switched current-free — the inrush currents of up to 200 × IN that a contactor has to damp simply never occur, and the 75-second discharge wait of a conventional bank is not needed either. The module carries its own intelligence: it monitors voltage, phase sequence, capacitor output and temperature continuously and reports operation and faults on two LEDs per phase. Triggering is a 10 … 24 V DC signal from a transistor-output PF controller such as BR6000-T or BR7000-T, a PLC, or the process itself; the TSM-LC-S variant is triggered over the system bus from a BR7000-I-TH/S485, which also displays and monitors up to 32 modules from the controller. Epkom holds the TSM-LC10, TSM-LC-N and TSM-LC-N1; the rest of the range is available to order.