Define frame size, sensor, sensor plug, and rating plug for Masterpact and Powerpact P and R breakers

Issue:
What is meant by frame size, sensor, sensor plug, and rating plug for Masterpact and Powerpact P and R breakers with Micrologic trip units, and how are they used to determine breaker amperage?

Product Lline:
Masterpact and Powerpact P and R frame circuit breakers with Micrologic trip units.

Resolution:

• Breaker frame has three general meanings. It is difficult to know what is being meant by “frame” without additional information and context.
  • The industry defines frame as the maximum current rating of a circuit breaker of a particular construction.
  • Breaker families are called “frames” such as P frame, R frame, W frame, etc.
  • Frame is also used to indicate the maximum setting possible for a particular circuit breaker.  For example, a PJ800 or PJ1200, or a 2000 A or 4000 A frame.
    In some cases though, this is misleading and frame designation alone does not necessarily indicate the maximum setting.
• The Micrologic trip unit is an electronic module that contains the protection and metering settings for the breaker and actuates the circuit breaker release mechanism.
• The sensor is an air-core Rogowski CT and is a permanent part of the circuit breaker; it cannot be changed out in the field or in the factory. The same Rogowski CT may be used in a range of breaker frames and amperages.
• The sensor plug is a plug fitted into the trip unit base under the trip unit and it sets the breaker’s maximum current setting. It can be replaced with the same type of sensor plug and in most cases can be changed out to another amperage.  The amperage can never be larger than the original sensor plug amperage for Powerpact, and never larger than the breaker frame size for Masterpact.  For example, an NW20 that came with a 1600A sensor plug could accept a 2000A sensor plug.  But it could not accept a 3000A sensor plug.
• The rating plug fits over the long time pickup and delay dials on the trip unit, and contains the multipliers that may be applied to the sensor plug to give the breaker its current rating. It is interchangeable and may be replaced with one with different multipliers to achieve different breaker ampacities.
• The performer plug is a non-replaceable component plug located adjacent to the sensor plug under the trip unit which defines the breaker type and instantaneous override setting and (for Masterpact) the close and latch rating.

Breaker amperage is the product of sensor plug value multiplied by the long time (Ir) setting.  The Ir setting is determined by which value on the rating plug the Ir dial is pointing to.

For more detailed information, including how the amp rating and trip curve is affected by the various components listed, please review the following documents.
Micrologic P instructions
Masterpact NW Catalog Micrologic Overview section

Released for:Schneider Electric USA