Introduction
Medium voltage HVL™ load interrupter switches are used in installations where reliable but infrequent load break switching is required. Load interrupter switches are often required to operate in harsh environments and are subject to moisture, particulates, abrasive and corrosive materials, and a wide range of temperatures. Additionally, long periods of time may pass between switching operations. Load interrupter switches require appropriate preventative maintenance to ensure continuous and proper operation. The three primary components of preventative maintenance are:
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A regularly scheduled maintenance program
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Correct maintenance procedures
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Qualified maintenance personnel
Some factors may make it necessary to schedule preventative maintenance more frequently than would otherwise be required. These factors include adverse operating environments and the severity and frequency of switching. Also, while maintenance scheduling will depend on the availability of downtime and qualified personnel, some abnormal conditions may require immediate attention.
Switch Operation
Square D's HVL load interrupter switches employ an electrical design where the contact for each phase consists of main contacts set parallel to a spring loaded arcing blade. The arcing blade opens after the main contacts to allow the arcing blade to interrupt the load current.
Square D HVL load interrupter switch operation
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Main and Arcing Contacts Closed |
Main Contact Open, |
Main and Arcing Contacts Open |