Magnum
24
1812.900A
3.6
Electronic tripping system
The Magnum circuit breaker utilizes a three part tripping
system (Figure 3-16):
• Microprocessor-based trip unit
• Current Sensors
• Trip Actuator
All three parts of the tripping system are discussed here,
except that the trip unit itself is not discussed in detail.
For detailed information pertaining to the different trip
unit models available with Magnum circuit breakers,
refer to the specific instruction leaflet dedicated to the
trip units (I.L. 70C1036 and I.L. 70C1037 ).
3.6.1
Microprocessor-based trip unit
Magnum circuit breakers use any one of a family of
Digitrip RMS trip units whose main features are
summarized in Table 3-1. Versions of the trip unit
without the “i” meet the USA National Electric Code
which specifies a maximum ground fault current setting
of 1200A; the trip units are otherwise identical. Note,
however, that the 1150/1150i trip units are not available
in the narrow frame circuit breaker.
Figure 3-13: Cross Section of Conductor and Arc Control
System
Figure 3-14: Integral Arc Runner Viewed From Top of
Arc Chamber (Arc Chute Removed, Circuit Breaker
Closed)
1. Integral Arc Runner
Figure 3-15: Magnum Arc Plate Assembly
1. Top
2. “V” Shaped Plates
3. Top Plate for Arcing Contact
1
1
2
3
2
