When the energy storage motor is overcurrent

What if the overload device does not carry the motor's starting current?

If the overload device does not carry the motor’s starting current, it may be increased, but it shall not exceed 140 percent of the nameplate current rating. The motor’s nameplate current indicates 203A. Doing the math, the overload protective device generally must not be greater than 253.75A.

What causes an electrical overload overcurrent?

An electrical overload overcurrent also occurs when a motor is mechanically overloaded. This may be caused by excess friction within its internal bearing surfaces, excess heat (due to high ambient temperature or another failure), or by the binding or some other mechanical overload in the utilization equipment it drives.

What is a motor overload?

The term “ overload ” describes a moderate and gradual rise in the value of current over a relatively long period of time. It is caused by excessive amounts of current drawn by a motor, which may be as high as six times the rated current. This is caused by too much load on a motor. Systems are protected by overload protection relays.

What is a motor overload protection device?

The motor overload protection device, #5, protects the motor and branch-circuit conductors from excessive overloads during motor operation and in the event the motor has trouble starting, 430.31. The motor branch-circuit short-circuit and ground-fault protection device, #2, protects the motor from these fault currents.

Where does electrical overload occur?

Overload conditions can occur at the service, feeder, or branch-circuit level of a building's electrical-power distribution system. An electrical overload overcurrent also occurs when a motor is mechanically overloaded.

Do I need sizing the overload protection for a motor circuit?

On to sizing the overload protection for this motor circuit. Remember that, if the motor is internally thermally protected, separate overload protection is not required. That is not the case in this example. Section 430.32 (A) (1) provides sizing requirements for overload protection that is supplied separately.