Mitsubishi Electric NF400-HEW, Instruction Manual

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3.4 Testing method of overcurrent trip
Test by using the “Y-351” breaker tester (option) or by energizing the MDU Breaker main unit.
If using the “Y-351” breaker tester, follow the instructions in that product's Instruction Manual.
This section describes how to test after energizing the MDU Breaker main unit.
(1) Send AC power to the MDU Breaker main unit from a 3-phase power supply or 1-phase power supply.
When using a 1-phase power supply, do so from two poles in series.
(2) Each operating current can be confirmed by checking the LEDs on the front of the MDU Breaker main unit.
Current adjustable resister Current adjustable resister
70% LED (green) : Acceptable when it begins to stay ON within 60% to 80% of current setting.
PAL LED (yellow) : With lp = 0.7
× lr, acceptable when it starts to flash every 0.5 seconds within 60% to 80% of current setting.
OVER LED (red) : Acceptable when it begins to stay ON at 105% to 125% of current setting.
(3) The long time delay and pre-alarm operating times can be confirmed by sending a current equivalent to 200% of current setting.
However, if a current exceeding current setting is sent prior to this test, the operating time will shorten and the first measurement will be invalid.
Tripping the MDU Breaker main unit will reset the trip circuit, allowing the following operating time to be measured correctly.
200% current
70% LED (green)
PAL LED (yellow)
OVER LED (red)
Pre-alarm operating time
Begins to stay ON
Long time delay operating time
Trip
Caution
● For the pre-alarm contact output for a MCCB (with alarm contact attached [optional]), the MDU is connected to the MDU Breaker main unit and
will not operate unless control power is applied to the MDU and the alarm contact output.
● The MDU measurement function, alarm function, fault cause and current display, and communication function cannot be confirmed if the
“Y-351” breaker tester is used.
Acceptable if measured operating time is within range below.
Measurement item
TL = 60 s TL = 100 s TL = 150 s
Pre-alarm operating time 24 to 36 s 40 to 60 s 60 to 90 s
Long time delay operating time 48 to 72 s
TL = 12 s
4.8 to 7.2 s
9.6 to 14.4 s
80 to 120 s 120 to 180 s