What is the purpose of the long time-lag thermal cutout on a dual-element fuse?

The long time-lag thermal cutout in a dual-element fuse is specifically designed to prevent unnecessary shutdowns of the motor. This safety feature allows for a certain amount of temporary overload, meaning that the motor can run momentarily above its rated load without immediately cutting off power. This is particularly useful in applications where transient conditions might cause temporary spikes in current, such as during motor startup or brief overload conditions. By allowing these temporary overloads without triggering an immediate shutdown, the thermal cutout helps maintain operational continuity and prevents interruptions due to harmless short-term situations that would not cause long-term damage to the motor.

In contrast, constant voltage provision, enhancing motor efficiency, and reducing operational noise are not roles fulfilled by a long time-lag thermal cutout. These aspects relate to different electrical principles and components that focus on performance and operational quality rather than on protecting the motor from overload conditions, which is the primary function of the thermal cutout in this context.