Question 87Electricity & Electronics - Assistant Engineer

A) They are closed only when the master switch is 'off'. This is the correct answer. The 'MS 1' contacts of the master switch are typically connected to the electrical circuit that controls the power supply to the equipment. When the master switch is in the 'off' position, the 'MS 1' contacts are closed, allowing the circuit to be energized and the equipment to function. Conversely, when the master switch is in any other position ('hoist', 'lower', etc.), the 'MS 1' contacts are open, interrupting the power supply and deactivating the equipment. The other answer choices are incorrect because they do not accurately describe the behavior of the 'MS 1' contacts in relation to the master switch position.