General Description - Megger BM25 Guia Del Usuario

GENERAL DESCRIPTION

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.
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.
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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
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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
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display.
Load automatically discharged at the end of a test, and
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decaying voltage (> 50 V) displayed.
Interlocked sliding cover to prevent simultaneous access of
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charging and test terminals.
Test terminal sockets lock test leads into the case and prevent
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accidental disconnection.
supply.