WACKER Group LTC 4, Repair Manual

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Electrical Troubleshooting Procedures LTC Repair
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7.17 Checking Individual Circuit Breakers
See Graphic: wc_gr002472
Electric shock hazard. Only qualified personnel should conduct this
test. Do not perform this test if you or the machine are wet.
Complete this test with the machine running. Test power to all circuit
breakers or just the circuit breaker in question.
7.17.1 Unplug the light(s) at the upper mast quick-disconnect plugs.
7.17.2 Remove the control panel front cover.
7.17.3 Place the main circuit breaker in the “ON” position.
7.17.4 Using the AC voltage setting on the multimeter, test for 120V±10%
incoming voltage by measuring across the input wires (a) (R/B, R, B/
W, or B) at the back of the circuit breaker(s) and neutral wires at the
terminal strip (b).
• If 120V±10% is not measured, it indicates a problem with voltage
reaching the circuit breaker. Check the continuity of the wiring
between the terminal strip and the circuit breaker. Repair or
replace the wiring as needed.
• If 120V±10% is measured at the circuit breaker, continue.
7.17.5 Place the circuit breaker being tested in the “ON” position and measure
the voltage between the outgoing side of the circuit breaker (c) and
neutral wires at the terminal strip (b).
• If 120V±10% is not measured, it indicates a problem with the cir-
cuit breaker. Check the continuity of the circuit breaker. Replace
the circuit breaker if needed.
• If 120V±10% is measured, voltage is being supplied through the
circuit breaker. Continue troubleshooting by checking the function
of control panel capacitors. See section Checking Incoming Volt-
age to Control Panel Capacitor(s).
WARNING