General Description - AVO MEGGER BM25 Guide De L'utilisateur

The BM25 is a compact, automated high voltage, battery powered
instrument used to carry out Polarization Index, Step Voltage, and
Dielectric Discharge tests as well as spot Insulation tests. The
BM25 has a resistance measurement capability up to 5 TΩ and
leakage current measurement enables resistances up to 500 TΩ to
be measured.
The design of the instrument takes full advantage of
microprocessor technology and features a large, clear liquid crystal
display, combining digital and analogue readings of insulation
resistance.
Set nominal voltage options of 500 V, 1000 V, 2500 V and 5000 V
are selectable. A variable output voltage setting provides a range
of 25 V to 5000 V incremental in 25 V steps.
At switch on, the instrument carries out a calibration self check
which automatically adjusts the measurement system. The
calibration sequence inhibits any testing if the measurement
system fails to meet preset limits.
On starting a test, the HV warning LED on the front of the
instrument flashes, together with the display HV warning
symbols. The integral timer starts automatically and displays
minutes and seconds elapsed since the start of the test. The
timer can be used to set the duration of a test, and will
automatically stop the output voltage when the set time has
expired.
During a test, measurements are automatically sent every 5
seconds via an isolated optical link to the RS 232 connector to
enable downloading of the results to a computer.
4

General Description

Battery capacity is continuously displayed by a segmented
indicator. The indicator flashes when the battery requires
recharging. Power is obtained from two parallel connected sealed
rechargeable lead acid batteries. If either battery fails (or an internal
protection fuse ruptures) the instrument will continue to operate on
the alternative battery. The battery is recharged by external 95 -
265V a.c., 50-60 Hz, or 12 V d.c.supply.
Charging connections, mains power indicator and instrument
protection fuses are located in a splashproof protected recess in
the front panel.
Specially designed lid hinges enable the lid to be removed and
replaced as required, and will protect the lid from strain or damage
by unclipping itself if unintentionally opened past its full extent.
Design safety features include:-
•
The flashing HV warning LED on the front of the instrument ,
and the flashing H.V. symbols on the display remind the user
that hazardous voltage is present when testing.
• External voltage >50 V displayed with flashing H.V. symbols on
the display.
•
Load automatically discharged at the end of a test, and
decaying voltage (> 50 V) displayed.
•
Interlocked sliding cover to prevent simultaneous access of
charging and test terminals.
•
Test terminal sockets lock test leads into the case and prevent
accidental disconnection.