General Description - Megger MJ10 Guide De L'utilisateur

General Description

The MJ10 and BM12 Insulation and Continuity testers are
completely self contained instruments to give
rapid and accurate measurement of insulation resistance and
continuity resistance. They fulfil the requirements of the VDE
0413 specification parts 1 and 4 (1980), and IEC 1010 -1, EN
61010 -1 (1995).
Both instruments have four insulation testing voltages 100
V, 250 V, 500 V and 1000 V with a single measuring range
for insulation resistance of 0 to 2000 MΩ and
each instrument has a 4 Ω resistance range making them
ideal for use when testing electrical installations to the
requirements of BS7671 (1992) (IEE Wiring Regulations).
The MJ10 uses a low voltage, hand cranked, brushless
a.c. generator as a power supply which is connected, after
rectification, to a d.c. to d.c. converter to provide the test
voltages. The generator is designed to be easy to turn even
under full load.
Power for the BM12 is derived from six 1,5 V alkaline
manganese cells mounted in a battery compartment in the
base of the instrument. The cells are connected to a d.c. to
d.c. converter to provide the test voltages.
Automatic discharge for capacitive circuits under test is
provided and both instruments have a 600 V a.c. range,
which is operative on any function providing the 'Test'
button is not pressed. Although calibrated for a.c. voltage
this range can be used to give an indication of the
discharging voltage level following testing of equipment
4
having capacitance. In addition, each instrument is provided
with a guard terminal which can be used to minimise the
effects of surface leakage when carrying out insulation
resistance tests.
In order to minimise the effects of standing e.m.f.'s when
continuity testing, two ranges are provided. This enables two
measurements, with opposite polarities of the test current, to
be made without altering the position of the test leads.
∞
. In addition
The instruments use a moving coil meter with taut band
suspension, white scales on a black scale plate and an
orange 'dayglow' pointer to indicate the insulation or
continuity resistance being measured.
Three 4 mm terminal sockets marked '+', '–' and 'G' are
provided on the side of the case for connection of the
test leads. After the test leads have been connected to
the instrument terminals, the carrying handle folds down
neatly over them. Should the handle accidentally become
detached from the case it may be easily 'sprung' back into
position. The case is robust, yet light-weight, and is made
from a strong polycarbonate plastic. Mounted on top of
the case is a six position, rotary, range selection switch and
a push-button 'Test' switch. On the BM12 an additional
push-button switch is provided to enable the battery
condition to be checked.