Surge arrestors from PT Limited are designed to offer surge protection to load cells from various surge events.
Voltage spikes can be caused by several factors including electrical surges, lightning, welding, electrostatic build and accidental mains connection.
A load cell is damaged when the voltage of the internal circuit is substantially different from voltage of the body, causing the insulation to break down.
Surge events may act in differing ways. For instance, a surge in a load cell cable raises the voltage in the cable above the voltage in the metal body of the cell, which is connected to the frame of the scale causing a breakdown of the insulation.
A lightning strike on a weigh bridge raises the potential of the load cell body to thousands of volts while the internal circuitry, which is connected through the cable to an indicator at a distance, may stay at normal potential.
PT100 surge arrestors from PT Limited limit the voltage rise occurring in the cable connected through the PT100SA glands relative to the brass stud protruding from the case of the PT100SA.
The connection of the brass earth stud of the surge arrestor is a crucial consideration as this affects the potential to which the voltage in the cables will rise.
PT100 surge arrestors should be installed as close as practically possible to the device being protected. In addition to load cells, these surge arrestors can also be used with electronic displays.