Magnum
48
1812.900A
Electrical Operation Functional Test
This test procedure is based on the assumption that the
breaker is equipped with optional shunt trip and spring
release accessories. If one accessory is missing,
substitute the manual button to replace the accessory’s
function.
Charge the breaker mechanism springs either using the
charging handle or the motor operator. Close the breaker
by applying rated voltage to the spring release accessory
and verify closing by noting the state of the indicating
flag. Charge the breaker mechanism springs either using
the charging handle or the motor operator. If using the
motor operator, disconnect power to it to prevent
automatic recharging. Open the breaker by applying rated
voltage to the shunt trip accessory. Close the breaker
using the spring release accessory. Is the breaker
closed? Open the breaker using the shunt trip accessory.
Is the breaker open? Repeat this entire described test
procedure three times.
Trip Unit Overload Functional Test
This test uses the Digitrip 1150 self test function, the
Digitrip Test Kit or the handheld Magnum Functional Test
Kit. Review test kit instructions for the trip unit.
Instruction leaflet 5720B55, section 1.2 or 1.3 applies for
instantaneous test procedures or paragragraph 5.2.1
“1150 Self Testing, Trip Mode” in the trip unit instruction
leaflet 70C1036.
Charge the breaker mechanism springs either using the
charging handle or the motor operator. Press the ON
pushbutton to close the breaker manually and verify
closing by noting the state of the indicating flag. Charge
the breaker mechanism springs either using the charging
handle or the motor operator. If using the motor
operator, disconnect power to it to prevent automatic
recharging. Trip the breaker with a trip unit test. Verify
that the trip indicator pop out button (if so equipped) is
“out” and then reset it. Press the ON pushbutton to
manually close the breaker. Is the breaker closed? Trip
the breaker with a trip unit test. Verify that the trip
indicator pop out button (if so equipped) is “out” and then
reset it. Repeat this entire described test procedure
three times. Reset the blinking red cause of trip LED on
the trip unit by pressing the Reset/Battery Test
pushbutton.
6.4.2
Arc chute inspection
When a circuit breaker experiences a high level fault or
during regularly scheduled maintenance periods, the
circuit breaker’s arc chutes and arc chambers should be
inspected for any kind of damage or dirt. Be especially
alert for signs of significant erosion of the V-shaped plates
inside the arc chute.
Arc chutes fit inside the arc chambers and down over a
the primary contacts. Each arc chute is held in place by
one top inserted screw (Figure 6-1). Begin by removing
the arc chute screws and all three arc chutes. Turn each
arc chute upside down to visually inspect the inside
(Figure 6-2).
Since the arc chutes are removed, this is an ideal time to
inspect primary contacts for wear using the circuit
breaker’s contact wear indicators. The details associated
with primary contact inspection are presented in the next
paragraph.
Figure 6-1: Top Rear View of Circuit Breaker with One Arc
Chute Removed
1. Arc Chute Removed
2. Baffled
Cover
3. Arc
Chamber
1
2
3