Motor Circuit Protector Vs Breaker

Typical thermal magnetic circuit.

Motor circuit protector vs breaker.

Capacity given in the table for the motor starter protectors the motor starter protector must be protected by a backup fuse. When used in tested motor starter combinations they provide complete ul listed motor control and protection and short circuit current ratings up to 100 000a. The mpcb can interrupt any electrical fault that is. See the following table for the maximum reated current for the backup fuse.

Locate where your motor falls in table 430 52 based on the full load current and motor size. Motor circuit protectors motor circuit protectors provide short circuit protection for individual motor loads and are available for a wide range of motor sizes and installation types. Circuit breakers which are called mcps or motor circuit protectors are sized with the intent to provide only short circuit and ground fault protection for the motor branch circuit protection per 430 52. To ensure safety in manufacturing plants it s important to understand the difference between a circuit breaker and a supplementary protector and the specific applications for each device.

A motor protection circuit breaker or mpcb is a specialized electromechanical device that can be used with motor circuits of both 60 hz and 50 hz it has several functions that allow it to provide a safe electrical supply for motors. The table will give you the size of the short circuit protection as a percentage of the full load current. Ul 489 circuit breakers are intended for installation in a circuit breaker enclosure or as parts of other devices such as service entrance equipment and panelboards they are regularly required on panel designs per the national electrical code. They can be combined with our nema and iec motor starters overload relays and contactors.

With a backup fuse according to the table the maximum short circuit current is permitted to equal the rated breaking capacity of the backup fuse. The difference between circuit breakers and supplementary protectors. Eaton s motor circuit protectors are ul recognized instantaneous only breakers for motor short circuit protection. This table is used to size the short circuit protection check the motor data sheets for the motor s full load current.

Ul 1077 supplementary protectors.