TRUE/FALSE: Disconnecting external DC power with the spike suppression switch in the START PROTECTION position will result in a DC Bus Short.

• A. FALSE
• B. Not Applicable
• C. Unknown
• D. TRUE

Answer: (D)

This question tests how the spike suppression circuit and START PROTECTION setting interact with the DC bus during power removal. When the spike suppression switch is in START PROTECTION, that path is arranged to clamp or absorb transient voltages that occur during start. If you disconnect external DC power while that protection path is engaged, the protective network remains connected across the DC bus, and with the main power source removed it can present a direct low-impedance path between the positive and negative sides of the DC bus. Any stored energy in the bus capacitors or in connected equipment then discharges through this path, effectively causing a DC bus short. So the statement is true because the START PROTECTION configuration creates the conditions for a short across the DC bus once the external power is removed.