Operating Description - Mitsubishi Electric MELPRO-A Series Instruction Manual

Structure
RUN indicated LED (Green)
It shows the result of self-
monitoring. It lights up in
normal condition.
Numerical display LED
Following item is displayed
by indicator select switch
setting.
・I measurement
0
・Pickup
・Setting value
・Fault record
・Clear fault record
・Forced operation (test)
Indicator select switch
The numerical display shows
according to this selection
switch. Don't leave
switch with halfway state.
Setting switches for
operation value and time
Set the setting values. The
black part is equal to maximum
value, but the
display is turned off.
Don't leave the switches with
halfway state.
Operation indicator reset lever
Move this lever up and down, then the operation indicator
resets. (Note) Don't pull the lever strongly.

Operating Description

1. Protection function
①The power supply can be derived from VT secondary.
②Set using condition switches according to your
using condition.
③When a ground fault occurs in a high-voltage
consumer site, the fault current flows between the
ground and the
distribution line or equipment, and the fault
current is detected by the MZT type zero-phase
current transformer (ZCT) and supplied to the
relay from the secondary output of ZCT.
④If input zero-sequence current is greater than or
equal to the setting value, the operation timer
starts. The relay actuates the output contact and
operation indicator after a preset time of the
operation timer.
⑤ For MGR-A3V-R type
this
numerical
Fig. 3-1 Structure of MGR-A3 series (front view)
ground capacitance
relay, after the
operation, if input zero-sequence current falls
below the setting value, the output contact will
be in the state set by the using condition setting
switch (auto-reset or self-hold).
For MGR-A3T-R type relay, the output contact is
auto-reset type. If you want to use the alarm
of the circuit as self-hold type, please build a circuit
as shown in Fig. 3-7.
The operation indicator keeps the operation status
(orange color). To reset the indicator, move the
reset lever up and down.
relay
9
Test button
By turning the indicator select
switch to "TEST" and pushing
"TEST" button for 2 seconds or
more, output contact can be
forced to operate (except for
the case of LOCK setting).
CPU reset button
While this button is pressed,
the relay function is locked
and the RUN indicated LED is
turned off.
In addition, the output contact
is reset from self-hold state
(MGR-A3V-R only).
Setting switches for using
condition
Don't use any tool with a sharp
point when the switches are set.
(It may cause damage to the switch
lever.)
SW1
ON
OFF
SW2 Output contact
ON Self-hold (Ho.)
OFF Auto-reset (FU.)
※SW2: MGR-A3V-R only
Factory settings are set to a
default of OFF.
Operation indicator
The indicator turns from black into orange
color when the protection element is put
into operation.
Frequency
50Hz
60Hz
JEP0-IL9555