Mechanically held relays and contactors are often used in auditoriums because
a) they have fewer coils than electrically held devices
b) they are quieter than electrically held devices
c) they are less expensive than electrically held devices
d) they are more reliable than electrically held devices
The correct answer and explanation is :
The correct answer is b) they are quieter than electrically held devices.
Explanation:
Mechanically held relays and contactors are commonly used in settings like auditoriums where noise levels need to be minimized. They offer a distinct advantage over electrically held devices in environments where maintaining a quiet atmosphere is important.
- Noise Level: One of the primary reasons mechanically held relays and contactors are chosen for auditoriums is that they are quieter than their electrically held counterparts. Electrically held devices typically require continuous power to maintain their contact positions, which results in a buzzing or humming sound as the electromagnet holds the contacts in place. This continuous operation creates a disruptive noise that can be intrusive in quiet environments such as auditoriums, theaters, or concert halls. Mechanically held relays, on the other hand, use a mechanical latch or mechanism to hold the relay in position after it is actuated. Once activated, the mechanical latch keeps the relay in place without needing continuous power, resulting in a quieter operation.
- Fewer Coils (a): While it is true that mechanically held relays can have fewer coils than electrically held devices, the main reason for their use in auditoriums is not necessarily the coil count but the noise they generate. The coil in an electrically held device continuously energizes to keep the contacts in place, leading to more noise.
- Cost and Reliability (c and d): Mechanically held relays can be more complex and, in some cases, more expensive to manufacture because of their mechanical components. Additionally, while they can be reliable, their reliability does not necessarily surpass that of electrically held devices. The latter are often simpler and may be considered more reliable in terms of fewer moving parts that can wear down.
In conclusion, the quieter operation of mechanically held relays and contactors makes them ideal for use in auditoriums, where noise reduction is crucial to ensure an optimal auditory experience.