Megger BM15 Data Sheet

BM15 MJ15

Analogue 5 kV Insulation Tester

 Four test voltages to 5 kV

 Dual power supply option giving the best of

both worlds

 Resilient mounted analogue scale for

robustness

 Voltage range to 600 V indicates auto

discharge

 Pass/fail overlays for rapid testing

 Single scale for insulation values to avoid

operator error

BM15 MJ15

Analogue 5 kV Insulation Tester

DESCRIPTION

The Megger® BM15 and MJ15 are compact 5 kV insulation testers.
They are very simple to use and provide a quick and accurate
reading of insulation resistance. The instruments use an analogue
display with a maximum reading of 20 GΩ. The BM15 is powered by
batteries. The MJ15 has an additional hand-cranked generator.

The instrument operation is extremely simple. A voltage range
enables measurement of a.c. or d.c. conductor potential. Four test
voltages are available at 500 V, 1 kV,

2,5 kV and 5 kV. A choice of push buttons is supplied; a locking
button simplifies long term testing, or a nonlocking version is
preferred for maximum safety.

A bezel allows a scale plate overlay to be added with pass/fail bands
for go/no go testing. This is particularly useful for less experienced
users and enables a rapid decision to be made.

The new instruments have a choice of power source. The BM15 is
powered by 8 x LR6 (AA) alkaline cells. The MJ15 comes with a hand
cranked generator plus batteries. If the test button is pressed the
MJ15 uses battery power. Otherwise the crank handle is turned to
save battery power or for use when the batteries are unavailable.

Both units are built into a rugged case designed for outdoor use.
The instruments are also supplied with a soft carrying case, a test
lead set, test record cards and batteries.

Safety terminals suitable for locking connectors are used for
connection to the test piece. An automatic discharge circuit
eliminates the voltage on capacitive loads after a test. The decaying
voltage can also be viewed on the scale.

Fused test leads are available as an option for voltage measurement.
The instruments meet the IEC1010 safety specification and EMC
specifications and are fully CE marked.

APPLICATION

Insulation is important for the safety of all electrical systems,
providing a barrier to hazardous live conductors. Insulation can
deteriorate due to the affects of moisture, sunlight and heat.
A reduction in the value of insulation resistance can lead to a
potentially dangerous situation caused by the dangers of electric
shock, or arcing causing fire. If insulation resistance is regularly
monitored unusually low values can be investigated before they
cause danger, or inconvenience and cost due to equipment
downtime for repairs.

The BM15 and MJ15 are general purpose, 5 kV insulation testers
for electrical contractors and engineers who test machinery,
transformers, switchgear, cables, etc.

This product is used by:

 Electrical Contractors

 Maintenance Engineers

 Telecommunications Engineers

 Gas and Water Utilities

 Railway Companies

 Cable Manufacturers

 Mining Companies

FEATURES AND BENEFITS

 Large, single scale analog display

 Auto voltage measurement function indicates conductor and

auto discharge potential

 Supplied with optional locking test button

 Safety recessed terminals and long connectors

 Four output test voltages

 Simple to use

 CE marked

 Dual power supply option on MJ15

 Unique scale overlay for pass/fail bands

 Resilient mounted analogue scale for robustness

 Single scale for insulation values to avoid operator error

 Light weight and rugged

 Range down to 100 kΩ ideal for go/no go testing

SPECIFICATIONS

Insulation range 100 kΩ to 20 GΩ (also 0 Ω and ∞)

Test voltage (d.c.)

Test voltage accuracy ±5% of nominal test voltages on 20 MΩ

Test voltage stability <±1% (180 r.p.m. to 240 r.p.m. MJ15)

Insulation accuracy (at 0 - 30 °C) (32 to 86 °F)

Short circuit/charge
current

Maximum capacitance
of load

Interference 1 mA rms at 50 to 60 Hz

Discharge resistor <500 kΩ

Voltmeter range 0 to 600 V a.c.

Voltmeter accuracy ±2,5% f.s.d. a.c.

Overload rating 720 V a.c. or d.c.

Scale length 2,8 in. (72 mm) (96°)

Power supply BM15

Battery life Typically 2000 five second tests at 5 kV

500 V, 1000 V, 2500 V and 5000 V

load

±2,5% of full scale deflection

1.5 mA ±0.5 mA

5 μF

(with rotary switch in the V position)

8 x AA cells (LR6
MJ15
Low voltage brushless Generator and 8 x
AA cells (LR6)

on 100 MΩ load

Battery indicator Loaded battery test

Safety Meets the safety requirements for double

insulation to IEC 61010-1 to installation
Category III***, 300 V phase to earth
(ground)

**Relates to transient overvoltage likely
to be found in special
equipment or parts of equipment,
telecommunication,electronic etc.

Non replaceable fuse 1 Amp, 250 V, HBC type (F)

(20 mm x 5 mm) to IEC 127/1
This fuse protects the instrument against
any faults occurring
when using rechargeable batteries.

EMC In accordance with IEC 61326-1

Operating temperature
range and humidity

32 °F to 86 °F (0 °C to 30 °C) at full
specification

-4 °F to 122 °F (-20 °C to 50 °C) with
temperature coefficient
±0,1%/°C (0,05% /°F)

Storage temperature

-13 °F to 149 °F (-25 °C to 65 °C)

range and humidity

Humidity 90% RH, 104 °F (40 °C)

Dimensions 220 mm x 160 mm x 115 mm

Weight BM15 Approx 2,6 lbs (1,2 kg)

MJ15 Approx 3,5 lbs (1,6 kg), or 4 lbs
(1,8 kg) with battery holder and cells.

Typical Terminal Voltage Characteristics

2