ALARM INDICATOR LED
The front LEDs turn ON when the power is supplied, and
OFF in an abnormality.
When one or more LEDs are OFF, check the following:
1) Measure voltage across the power supply terminals with
a multimeter.
2) When DC power supply is confirmed, replace the M-
RESTER with a new one.
3) When the voltage is 0V, supply appropriate DC voltage
and check the LEDs. If one or more LEDs are OFF, re-
place the MRESTER with a new one.
MAINTENANCE
Check M-RESTER periodically. Many cases of lightning are
ignored, and even lightning at a far distance often causes
inductive surges.
Even with the alarm indicator LEDs on the MDH unit, 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
WIRING
• Make sure that wiring is done as instructed in the con-
nection diagram.
• Make sure that the Ground terminal (2, 3, 6 or 7) is con-
nected to the metallic housing of protected equipment.
• Make sure that the Ground terminal (2, 3, 6 or 7) is
grounded to earth.
■
DISCHARGE FUNCTION
Remove all the wires before testing its discharge capability
as follows:
• Check resistance across the terminals indicated below.
(Indicator of the tester shows ≥10MΩ.)
(1) – (8), (1) – (2), (8) – (2)
• Check that discharging occurs across the same terminals
with a 500V DC megger. (Indicator of the megger shows
≤20MΩ.)
• If any of the above tests shows negative, replace the whole
MRESTER unit.
MDH
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-8169 Rev.5 P. 3 / 3
