What condition is described when a motor shaft cannot turn due to heavy loading?

What condition is described when a motor shaft cannot turn due to heavy loading?

• A. Fully loaded
• B. Locked rotor
• C. Ground fault
• D. Short circuit

Answer: (B)

The condition where a motor shaft cannot turn due to heavy loading is known as a locked rotor condition. In this scenario, the rotor is effectively "locked" in place and cannot rotate, which typically occurs when the motor is subjected to a load that exceeds its capacity. This can happen due to mechanical binding or an overload condition. In a locked rotor state, the motor draws a high initial starting current, which can be several times greater than its normal operating current, leading to potential overheating and damage if not addressed promptly. This condition is distinct from simply being fully loaded, which refers to a motor running under its designed load without difficulty. Ground faults and short circuits are electrical issues that pertain to unintended paths in electrical circuits or circuit interruptions but are not directly related to the mechanical inability of the rotor to turn due to loading conditions. Thus, the focus on the mechanical aspect of the rotor being unable to move due to excessive load is what identifies this condition as a locked rotor scenario.

The condition where a motor shaft cannot turn due to heavy loading is known as a locked rotor condition. In this scenario, the rotor is effectively "locked" in place and cannot rotate, which typically occurs when the motor is subjected to a load that exceeds its capacity. This can happen due to mechanical binding or an overload condition. In a locked rotor state, the motor draws a high initial starting current, which can be several times greater than its normal operating current, leading to potential overheating and damage if not addressed promptly.

This condition is distinct from simply being fully loaded, which refers to a motor running under its designed load without difficulty. Ground faults and short circuits are electrical issues that pertain to unintended paths in electrical circuits or circuit interruptions but are not directly related to the mechanical inability of the rotor to turn due to loading conditions. Thus, the focus on the mechanical aspect of the rotor being unable to move due to excessive load is what identifies this condition as a locked rotor scenario.