Disconnect and earth switch test

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Information about Disconnect and earth switch test

Published on October 17, 2016

Author: davidroy39

Source: slideshare.net

1. DISCONNECT AND GROUNDING SWITCH TEST MECHANICAL CHECK AND VISUAL INSPECTION ü Inspect for physical damage/defects ü Check Nameplate Information for Correctness ü Check Tightness of all Bolt Connections.(torque wrench) ü Check quality of galvanizing (if applicable) ü Check Smoothness and Easy Operation ü Check Simultaneity and Synchronism of all 3poles during closing ü Check for Proper Contact, Fingers Spread and contact Pressure in Fully Closed Position ü Check Open gap and Min. Clearance Between phase and to Ground ü Check that end of travel stops are correctly, adjusted, set and locked in position ü Check that Switch is Pad-Lockable in Both Closed and Open Position ü Check switch opens more than 90˚(for horizontally mounted vertical open disconnects) ü Check switch drive linking toggled in both closed and open position ü Check that Grounding Connection is Securely Tightened

2. ü Check that Switch Operating Handle is Grounded ü Check Mechanical Interlocking ü Check that operator’s platform is of adequate size and properly grounded ELECTRICAL TEST ü Measure resistance of main current path (terminal to terminal) at 100A DC. ü Functional test of all electrical interlocks. ü Check position-signaling contacts(if applicable) ü For motor operated mechanisms: a. Check mechanism cabinet is grounded. b. Check correct setting of motor limit switched (open/close). c. Check correct operation of all auxiliary “a” and “b” contacts. d. Measure switch opening and closing times and motor current at rated voltage (for fast acting disconnects and grounding switches, perform a timing test with an oscillograph). e. Minimum voltage operation (close and open) at 90V DC. f. Functional checks of thermostat and space heaters. Measure heater current. g. Insulation test all control and power wiring /cables at 500V DC h. Check that in the manual mode, insertion of the operating handle automatically disconnects the motor DC supply. ü For bus bar isolators, carefully check make and make before brake contact function for auxiliary switch contacts used for CT switching schemes during open close time test on disconnect main contacts.

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