The
BM11D
and
BM21
are compact, battery powered, high
voltage d.c. insulation testers with resistance measurement
capabilities to around 1 T
Ω
. The
BM11D
has a digital full scale
of 500 G
Ω
whilst the
BM21
can measure up to 5 T
Ω
. The
BM21
can be set to display leakage current instead of
resistance and this mode of operation also allows higher
resistances to be measured, possibly up to 500 T
Ω
.
The instruments are microprocessor controlled and feature a
large, clear LCD combining digital and analogue readings of
insulation resistance.
Both instruments have test voltage positions of 500 V, 1000 V,
2500 V and 5000 V. The
BM21
has an additional range with a
variable output voltage of 25 V to 5000 V in 25 V steps.
An integral timer is started automatically on commencement of
the test, and displays elapsed minutes and seconds since the
start of the test. The
BM21
timer can be used to set the
duration of test, and will automatically stop the output voltage
when the time has expired.
At the end of a test, capacitive loads are discharged
automatically and the decaying voltage is displayed as the
value returns to zero. The test leads should not be
disconnected until the item has been discharged fully. Similarly,
during a test the test leads should not be removed, and the item
under test should not be touched. A flashing LED, and flashing
high voltage symbols on the LCD remind the user that
hazardous voltage is present.
A battery symbol is displayed continuously showing the
condition of the battery.
Power is obtained from internal mains rechargeable batteries.
To recharge the batteries requires an input voltage within the
range 95-265 V a.c., 50-60 Hz. The power input and fuses are
located in a splashproof recess on the front panel.
Battery Charging Power cord:
If the power cord plug is not suitable for your type of socket
outlets (receptacles), do not use an adaptor. You should use a
suitable alternative power cord, or if necessary change the plug
by cutting the cord and fitting a suitable plug. The colour code
of the cord is:
Earth (Ground)
Yellow/Green
Neutral
Blue
Phase (Line)
Brown
If using a fused plug, a 3 Amp fuse to BS 1362 should be fitted.
Note: A plug severed from the power cord should be destroyed,
as a plug with bare conductors is hazardous in a live socket
outlet (receptacle).
4
General Description
