This table is used to size the short circuit protection check the motor data sheets for the motor s full load current.
Motor circuit protector vs breaker.
The table will give you the size of the short circuit protection as a percentage of the full load current.
They can be combined with our nema and iec motor starters overload relays and contactors.
Other means such as overload relays provide the motor overload protection.
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.
Locate where your motor falls in table 430 52 based on the full load current and motor size.
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.
Eaton s motor circuit protectors are ul recognized instantaneous only breakers for motor short circuit protection.
Ul 1077 supplementary protectors.
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.
Ul 489 circuit breakers.
Protection against electrical faults such as short circuits line to ground faults and line to line faults.
Capacity given in the table for the motor starter protectors the motor starter protector must be protected by a backup fuse.
See the following table for the maximum reated current for the backup fuse.
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.
Typical thermal magnetic circuit.
The mpcb can interrupt any electrical fault that is.