Mitsubishi Electric C Series Handling And Maintenance page 54

(8) MG (Insulation switch)
This switch is attached for insulation resistance measurement between rihght and left poles of the models to
which control power is supplied through the right and the left poles, such as earth leakage circuit breaker.
Connecting a switch interlocked with the handle to one con-
trol circuit and turning off the circuit breaker opens the control
circuit making it possible to carry out insulation resistance
measurement. Even with the standard breakers, insulation
resistance measurement is possible between a charged part
and ground, the left pole and the middle pole, and between
the middle pole and the right pole. Insulation resistance mea-
surement between the left pole and the right pole only reduce
the indication to zero but never breaks the ELCB.
(9) PAL (Pre-alarm module)
This module functions to give alarm output when load current exceeds a preset current level and
serves for securing continuous power supply and also for preventive maintenance. The electronic
breakers with mount digital ETR of 100 to 800A frames are provided with this module as an option.
(Some models are with this module as the standard equipment.)
(1000 to 2000A frames are prepared for exclusive use.)
Type
NF100-SEP NF100-HEP
NF250-SEW NF250-HEW
NV100-SEP NV100-HEP
NV250-SEW NV250-HEW
NF400-SEW NF400-HEW
NF630-SEW NF630-HEW
NF630-REW
NF800-CEW NF800-SEW NF800-HEW
NF800-REW NF800-UEW
NV400-SEW NV400-HEW
NV400-REW
NV630-SEW NV630-HEW
NV800-SEW NV800-HEW
Note 1. Pre-alarm module is normaly self-holding. Auto reset can be produced upon request.
1 1 1 1 1 Pre-alarm LED
2 2 2 2 2 Solid state relay output
3 3 3 Pre-alarm module
3 3
Pre-alarm characteristics (100 and 250A frames)
4h
2h
1h
Characteristics
30min
20min
14min
10min
LTD working duration TL
60-80-100s (at 200%)
6min
4min
2min
1min
Pre-alarm
30s pick-up current
Inx(0.70-0.75-0.8-
20s
0.85-0.9-0.95-1.0)
10s
Pre-alarm working duration
5s
Tp= TL (at200%)
2
2s
60 70 100 125 200 300 400 500600700 1000
Current
(percentage against rated current or specified rated current)
Be careful to electrification, ground fault, and contact with the main circuit as PAL output is internally
connected with the control power source.
Solid state relay (SSR) output-Contactless output
Pre-alarm LED
(Auto reset)
(Auto Reset)
Option
Standard
equipment
Option
The LED starts blinking on the circuit breaker when load current exceeds the preset current, then changes to
continuous glowing when pre-alarm output is given.
Open the upper cover of the circuit breaker, connect the connector of the lead wire packed together, and use it
as the lead wire outlet. In this case, only the lead wire output of the internal accessories can be attached to the
right pole. (For flush plate type, the outlet is manufactured in advance as PAL mount.)
SLT is attached as a standard equipment and is used as the control power source of AC100V or AC200V. In this
case, no other internal accessories can be attached to the right pole. (Auto resetting is also applicable.)
Pre-alarm characteristics (400 to 800A frames)
10hr
5hr
Pre-alarm
2hr
Operating 1hr
30min
20min
14min
10min
6min
4min
2min
1min
100s
30sec
20sec
50s
10sec
5sec
2sec
1sec
0.5sec
0.2sec
0.1sec
Percentage (%) to rated current or preset current rating
Operation of insulation switch
Condition of
circuit
breaker
Condition
of
Insulation
switch
Switching capacity Auto reset
DC24V·AC100·200V
20mA
—
Option
(Note 1)
DC24V·
AC100·200V
20mA
Pre-alarm pick-up current
LTD operating time T
L
±
12 – 60 – 100 – 150sec 20%
(at 200%)
Pre-alarm
pickup current I
P
×
( 0.7– 0.75
Ir
– 0.8 – 0.85 – 0.9
– 0.95 – 1.0 ) ±
10%
Pre-alarm
operating time T
P
T
L
±
T = 20%
P
2
( at 200% )
60 70 100125 200 300 400 500 600700 1000 1500
Current
CAUTION
OFF or trip
Insulation switch (Open) Insulation switch (Close)
Pre-alarm module-Contact output (1a)
Self-holding Switching capacity
AC100V or
AC200V 2A
Option
AC125V 2A AC250V 2A
DC30V 2A DC100V 0.3A
PAL OUT LED
Reset switch
RESET
Indicator lamp (Example)
618
L (AC 100V or AC 200V)
2
Control power pre-alarm output
L
1
(617)
In the case of flush plate type, this is mounted on back
side of the circuit breaker.
ON
Reset system
Press the reset
switch or turn off
control power.
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