The maximum size of a fuse placed in the electrical circuit with a motor having a low starting load should have a current rating load of

The maximum size of a fuse placed in the electrical circuit with a motor having a low starting load should have a current rating load of

• A. The same as that of the motor.
• B. One and one-half times that of the motor.
• C. Three times that of the motor.
• D. Three-fourths the size of the motor.

Answer: (B)

In an electrical circuit with a motor that has a low starting load, the maximum size of a fuse should typically be rated at one and one-half times the motor's full load current. This is because motors generally draw a higher starting current than their running current, sometimes as much as five to seven times the full load current, depending on the motor and load conditions. Using a fuse rated at one and one-half times the motor's current provides sufficient protection against overcurrent conditions while accommodating the initial inrush current when the motor starts. This prevents nuisance blowing of the fuse during the normal starting phase, allowing the motor to operate effectively without compromising safety or damaging electrical components. Selecting a fuse that strictly matches the motor's current could lead to frequent fuse failures during start-up due to the higher inrush current, while a fuse rated at three times the motor's load may not offer adequate protection against overloads during normal operation. Therefore, the one and one-half times rating strikes a suitable balance between protecting the motor and ensuring reliable operation during start-up conditions.

In an electrical circuit with a motor that has a low starting load, the maximum size of a fuse should typically be rated at one and one-half times the motor's full load current. This is because motors generally draw a higher starting current than their running current, sometimes as much as five to seven times the full load current, depending on the motor and load conditions.

Using a fuse rated at one and one-half times the motor's current provides sufficient protection against overcurrent conditions while accommodating the initial inrush current when the motor starts. This prevents nuisance blowing of the fuse during the normal starting phase, allowing the motor to operate effectively without compromising safety or damaging electrical components.

Selecting a fuse that strictly matches the motor's current could lead to frequent fuse failures during start-up due to the higher inrush current, while a fuse rated at three times the motor's load may not offer adequate protection against overloads during normal operation. Therefore, the one and one-half times rating strikes a suitable balance between protecting the motor and ensuring reliable operation during start-up conditions.