MOST Designers have a pretty good design of what a circuit breaker is and what it does; if you need a refresher, here ’s a quick definition:

  

  

  Then, then

  Circuit Breakers 101

  Suitable for your application.

  The Circuit Breaker to Trip at the Given Current. The Widths of the Curves Indicate Typical Tolerances. It’s Recomgeded that You Consult A Data SHEET FOR MOREIREMATION.

  Deteting Factors

  , DERATING FACTORS MST Be Applied.

  Circuit breaker on overload will be reduced; the reverse applies at low testures.

  The Low End, Even DC Operation Can Cauting Ises with Extinguishing The Arc that Occurs when the contaments are sitting applications.

  And Perhaps Even Mounting Position. Circuit Breaker ManuFacturers Provideo DABLES and Operating GuideLine in this this task. WHEN in Double.

  Packaging

  

  Standards and Safety Agencies

  And qualification requirers.

  Step-By-STEP Selection Procedure

  parameters.

  Step 1: Basic Electrical Parameters

  a) What is the voltage? IS it ac or dc? If ac, What Frequency?
b) What is the normal loadurrent? Trip Current?
c) NUMBER of Poles and Type — Normally Open (n/o) or Normally Closed (N/C)?
d) Are Any Electrical Sepate Auxiliary Contacts NEEDED? N/OR N/C?
E) Required Trip Characteristic (See Time/Current Curves Above)

Step 2: Other Required Features

  a) Mechanical form factor (E.G. DIN RAIL, Panel Mount, Standalone, ETC.), OR SIZE Constraint?
b) Connection Method?
c) AdDitional Features required?

Step 3: Operational Considerations

  a) ENVIRONMENTAL C.
b) Required Safety Approvals
c) Industry-Spectry-Specific Requirements (E.G. Automotive, Aviation, Medical, Hazardous Operation, MIL STD, ETC.)

Design exmple

  To Illustrate the Process, Here ’s a real-all design example.

  blow (delay) and Fast-Acting Types.

  Basic Electrical Parameters:

  Operating voltage: 24VDC

  Normal loadurrent: 10 @ 5A EACH

  Number of point and type: Single Pole

  Required Trip Characteristic: 100ms Trip Time (APPROXIMATELY) at 3 Times Rated Current to Replicate Performance of Fusesses

  Other Required Features

  Mechanical Form Factor: PCB Mount, Small Size (Approximately 1 Inch by 1 Inch)

  Connection method: Solder Terminals

  Additional Features Required: PROVIDE Indication of Tripped State (Auxiliary Contory/Alarm); Switchable; ResetTable

  Operational consaturerations

  ENVIRONMENTAL CONDINONS: High Shock and Vibration Specifications (Seismic Testing is Part of the Customer ’s Approval Process)

  Enclosed Cabinet Installation with Temperant EXCURSIONS

  Selection Process

  Window, Ruling It Out as a POSSIBLE SOLUTION.

  

  +70 rC Range; And is mounted subtyic circuit breaker on a symmetrical din rail that can be plugged into a PCB.

  The Result was a very satisFied Customer.


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