ARRESTER MODULE ELEMENT
The MEH indicates its failure with contact output (ON) and
front indicator LED (red). In such condition, replace the
MEH as soon as possible.
■
REPLACING THE MEH
Remove the screws attaching the clamps to the MMH body,
and pull the MEH off. Plug a new MEH into the socket and
secure the clamps with the screws. (See the figure below.)
MEH Socket
MEH
MEH MTG HOLE
2–3 (.12) dia.
• Clamps
Clamp Guide
Clamp
The replacement MEH is available with following model No.
MEH-1: for 100V/110V AC power
MEH-2: for 200V/220V AC power
We recommend that you keep spare MEHs so that you can
replace them when necessary.
MAINTENANCE
Check M-RESTER periodically. Many cases of lightning are
ignored, and even lightning at a far distance often causes
inductive surges.
We recommend that you check your M-RESTER about twice
a year, before and after the rainy season. Check whenever
you experience a strong lightning occurrence.
Checking procedure is explained in the following:
■
CHECKING
A) ALARM Contact and LED:
Check the ALARM contact relay status and its LED on
the front of the MEH. When the red light is turned ON,
unplug the MEH and return it again, and check that the
light is still ON. Then replace the MEH according to the
procedure described in the left. If the light turns OFF
when you return it, continue use of the unit as this is
standard operation.
B) RUN LED:
If the RUN LED (green) remains OFF when you turned
the power supply ON, replace the MEH.
C) Wiring:
Make sure that the terminal (3) is connected to the me-
tallic
housing of the unit and that of protected equipment.
D) Discharge Function of the MEH:
Remove the MEH and test its discharge capability as fol-
lows:
• Check resistance across the following terminals: (3) – (4),
(3) – (6), (4) – (6) (infinite standard).
• Check that discharging occurs across the same terminals
with a 1000V DC megger. (Indicator of the megger reach-
es overscale.)
•
E) Leakage Current (between lines)
Return the MEH and apply supply voltage across the
terminals (1) – (2) with no load, and measure current at
the terminal (1). (≤50mA standard for MEH-1; ≤30mA
for MEH-2)
4
1
5
8
3
2
6
7
MEH
Rear View
(pin terminals)
F) If any of the above tests shows negative, replace the MEH
after that you confirm that the main body unit functions
properly with the following tests. If the following tests
show negative, replace the whole M-RESTER unit.
G) Main Body Unit Test
• Remove the MEH and all wiring and check resistance
across the following terminals. (≤0.5Ω standard)
Terminals (1) – (4), (2) – (5)
• With the MEH and all wiring detached, check resistance
across the following terminals. (infinite standard)
Terminals (1) – (2), (1) – (3), (2) – (3)
• Check that discharging occurs across the same terminals
with a 1000V DC megger. (Indicator of the megger reach-
es overscale.)
MMH
5-2-55, Minamitsumori, Nishinari-ku, Osaka 557-0063 JAPAN
Phone: +81(6)6659-8201 Fax: +81(6)6659-8510 E-mail: [email protected]
EM-8179 Rev.4 P. 4 / 4
