MIT515, MIT525, MIT1025
5-kV and 10-kV dc Insulation Resistance Testers
MIT515, MIT525, MIT1025
5-kV and 10-kV Insulation Resistance Testers
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Industry best guard terminal accuracy
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Compact and lightweight for easy
transport and use
PI, DAR, DD, SV and ramp test
Unique dual case design provides
additional user protection
Lithium-ion battery - extended capacity,
rapid charge
Advanced memory with time/date stamp
CATIV 600 V safety rating on all terminals
DESCRIPTION
The new range of insulation resistance testers consists of
three models: two 5 kV units (MIT515 and MIT525) and a
10 kV unit (MIT1025). Resistance measurement is available
up to 10 TΩ for the 5 kV models and 20 TΩ for the 10 kV
model. The new instruments are smaller and lighter than
previous models yet offer advanced features and rapid
charge capability.
A key productivity feature is the ability to take
measurements when connected to line power/mains with
a dead battery. Intelligent battery charging ensures the
optimum charge rate as a function of battery level, resulting
in minimum charge times.
The rugged, unique dual case design provides the ultimate
protection for a portable instrument and a clip-on lead
pouch ensures that leads remain with the instrument at
all times. The case lid is removable for improved terminal
access. IP rating is IP65 with the case closed preventing
water/dust ingress. High reliability and safety are built in;
all models are safety rated to CATIV 600 V and are double
insulated.
Five preset voltage ranges are provided in insulation
test mode, plus a user settable lock voltage range. Any
selectable test voltage may be locked and restored
via the selector switch, thereby increasing efficiency
of commissioning and repetitive tests. Preconfigured
diagnostic tests include Polarization Index (PI), Dielectric
Absorption Ratio (DAR), dielectric discharge (DD), Step
Voltage (SV) and ramp test.
The ramp function gradually increases voltage up to a
selected level while graphing current vs. voltage (graph
downloadable). Graphs can be compared to example
curves in IEEE 95-2002 to reveal a variety of faults difficult
to detect otherwise. Small defects can be easily detected
without risking the sudden large voltage increments
produced by a Step Voltage test. Monitoring the developing
graph during test enables the operator to terminate prior
to breakdown, thereby reducing the possibility of damage
to already flawed insulation. These units are particularly
informative on polyester, asphalt and epoxy-mica
insulations. They can also test voltage suppression devices.
Simplicity of operation is achieved with two rotary switches
and the large backlit display enables multiple results to be
displayed simultaneously.
Advanced memory storage includes time/date stamping of
results, logging of data and recall of results to screen. A
fully isolated USB device interface (type B) is used for safe
transfer of data to Megger’s PowerDB asset management
software.
Typical end users include:
Electrical contractors
Testing and service companies
Wind farm and solar generation operators
Power generation and distribution companies
Industrial companies
Rail companies
MIT515, MIT525, MIT1025
5-kV and 10-kV dc Insulation Resistance Testers
FEATURES AND BENEFITS
Smaller size and lighter weight allows easier transport
and use without compromising performance.
High measurement range enables installation testing and
long-term trending of higher value apparatus.
Unique dual case design allows for fire-retardant
protection while maintaining ruggedness.
High-quality, flexible silicon test leads meet safety
regulations of IEC 61010-31:2008 while ensuring
measurement accuracy.
Timed IR plus PI, DAR, DD, SV and ramp tests maximize
diagnostic testing capability.
Operate from line power when battery fully discharged
(charges while operating).
Two and one-half hour full battery charge time (one-half
hour charge for one hour testing) significantly increases
productivity.
Up to six hours continuous testing (5 kV) on a single
battery charge.
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Industry best guard terminal performance to insure
highest accuracy of measured values.
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Enhanced driver technology provides plug-and-play
when connected to the internet. No tedious and
potentially interruptive setup procedures.
Dedicated voltmeter function (30 V to 660 V) with
frequency measurement allows the user to check for
induced voltages.
CATIV 600 V safety rating on all terminals allows for
safe use in the widest range of applications.
Large LCD with automatic backlight.
Noise filter rejects up to 3 mA noise for effective
operation in electrically noisy environments.
High altitude operation up to 3000 m while maintaining
CATIV 600 V rating.
Rotary switch operation for easy, intuitive field use.
Field replaceable battery.
Locking test leads provide additional safety.
3 mA short circuit current with unique max power
regulations technology ensures maximum transfer
whatever the load until selected voltage is reached.
5% accuracy all the way up to 1 T-ohm at 5 kV and
2 T-ohm at 10 kV ensures highest accuracy where it
matters most.
Date and time-stamped test results reduce the risk of
error in result interpretation.
APPLICATIONS
The units are designed for testing the insulation of highvoltage electric equipment. Their wide voltage range
also allows applications for low-voltage equipment.
Generators, motors, transformers, cables and switchgear all
require effective maintenance. The test techniques on the
instruments provide valuable diagnostic information.
All three instruments test the insulation resistance of:
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High-voltage power cables and high-voltage buses
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Large motor/generator windings
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Line and substation transformers
The MIT525 and MIT1025 also perform spot tests, stepvoltage tests, dielectric discharge tests, ramp tests, and
dielectric absorption tests for the following applications:
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Acceptance testing at installation to check conformance
to specifications.
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Routine preventive/predictive maintenance testing after
installation.
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QA testing as part of the manufacturing process.
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Diagnostic testing to isolate faulty components for repair.
With its higher voltage testing capability, the MIT1025 is the
perfect everyday work tool for manufacturers, users and
maintainers of rotating machinery. Designed in accordance
with the requirements of IEEE43:2000, the MIT1025 is ideal
for measuring the insulation resistance of armature and
field windings in rotating machines rated 1hp (750 W) or
greater. The standard applies to synchronous, induction
and dc machines as well as synchronous condensers.
What is the IEEE Standard 43-2000?
In March 2000, the IEEE-SA Standards Board approved
a revision of IEEE Std 43-1974 by the Electric Machinery
Committee of the IEEE Power Engineering Society. This
revision is IEEE Std 43-2000, the “IEEE Recommended
Practice for Testing Insulation Resistance of Rotating
Machinery.” Following is a brief summary of its highlights:
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Test voltages up to 10 kV are recommended for
windings rated greater than 12 kV.
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Both the insulation resistance and the polarization index
test are recommended.
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Test results should be compared to historical values to
identify changes.
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In lieu of historical records, minimum acceptable values
(based on the type of equipment) for both tests are
indicated.
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Depending on the machine rating, the readings for one
or both tests should exceed the minimum acceptable
values.
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If the readings are below the minimum acceptable
values, the winding is not recommended for an overvoltage test or for operation.
MIT515, MIT525, MIT1025
5-kV and 10-kV dc Insulation Resistance Testers
SPECIFICATIONS
Insulation Range, Analog
100 kΩ to 10 TΩ
Insulation Range, Digital
MIT515 & MIT525: 10 kΩ to 10 TΩ
MIT1025: 10 kΩ to 20 TΩ
Test Voltages
MIT515 & MIT525: 250 V, 500 V, 1000 V, 2500 V, and 5000 V
MIT1025: 500 V, 1000 V, 2500 V, 5000 V, and 10,000 V
User Defined Test Voltages
MIT515 & MIT525: 100 V to 1 kV in 10 V steps,
1 kV to 5 kV in 25 V steps
MIT1025: Same as above plus 5 kV to 10 kV in 25 V steps
Accuracy (23º C)
MIT515 & MIT525: ±5% to 1 TΩ, ±20% to 10 TΩ
MIT1025: ±5% to 2 TΩ, ±20% to 20 TΩ
Voltage Output Accuracy (0ºC to 30ºC)
+4% -0% ±10 V of nominal test voltage at 1 GΩ load
Voltmeter Range
30 to 660 V ac or dc, 50/60 Hz
Accuracy: ±3% ±3 V
Frequency range: 45 Hz to 65 Hz
Short Circuit Current
3 mA nominal, max. power on all loads outperforming many
5 mA testers
Insulation Alarm
100 kΩ to 1 GΩ
Current Measurement
Range: 0.01 nA to 6 mA
Accuracy: ±5% ±0.2 nA at all voltages
Capacitance Range (above 500 V)
10 nF to 25 µF (dependent on measurement voltage)
Accuracy (23ºC): ±10% ±5 nF
Capacitor Charge
MIT515 & MIT525: <3 s per µF at 3 mA to 5 kV
MIT1025: <5 s per µF at 3 mA to 10 kV
Capacitor Discharge
MIT515 & MIT525: <250 ms/µF to discharge from 5000 V to 50 V
MIT1025: <500 ms/µF to discharge from 10,000 V to 50 V
Timer Range
Up to 99 minutes, 15 seconds minimum setting
Memory Capacity
5-1/2 hours continuous logging every 5 s.
or 33 logged PI tests
or 350 logged IR tests
Industry-Standard Tests
MIT515: IR, IR(t), DAR, PI
MIT525 & MIT1025: IR, IR(t), DAR, PI, SV, DD, Ramp Test
Interface
USB type B (device)
Real Time Output
USB, 1 reading/second (voltage, current and resistance)
Interference Rejection
MIT515 & MIT525: 1 mA per 250 V up to a maximum of 3 mA
MIT1025: 1 mA per 600 V up to a maximum of 3 mA
Guard Terminal
2% error guarding 500 kΩ leakage with 100 mΩ load
Voltage Input Range
85 to 265 V, 50/60 Hz, 60 VA
Battery Type
Lithium-ion, 11.1 V, 5.2 A hour, meets IEC 62133:2003
Battery Life
MIT515 & MIT525: Typical capacity 6 hours continuous at 5 kV
with a 100 MΩ load
MIT1025: Typical capacity 4.5 hours continuous at 10 kV with a
100 MΩ load
Battery Charge Time
2.5 hours from deep discharge, 2 hours normal discharge
30 min. quick charge: 1 hour operation at 5 kV, 100 MΩ
Safety
Meets the requirements of IEC61010-1 CAT IV 600 V
Default voltmeter warns operator of applied voltage above 50 V
EMC
Meets the requirements of IEC61326-1
Ingress Protection
IP65 (lid closed); IP40 (lid open)
Temperature Range
Operating: -4ºF to +122ºF (-20ºC to +50ºC)
Storage: -13ºF to +149ºF (-25ºC to +65ºC)
Humidity Range
90% RH @ 104ºF (40ºC)
Altitude
3000 m, CAT rating maintained >2000 m*
(*test load connected)
Dimensions
12 in. x 11 in. x 7 in. (315 mm x 285 mm x 181 mm)
Weight
10 lb. (4.5 kg)
Fig. 1: Quality insulation testers exhibit fast voltage rise
times to resistance levels commensurate with minimum
acceptable values, and maintain selected voltage
throughout the remaining measurement range. Below an
acceptable level of resistance, rapid voltage drop protects
the test item from exposure to high voltage, so that it may
be reclaimed by appropriate maintenance.
Product comparison guide.
A look at each instrument’s features.
MIT515, MIT525, MIT1025
5-kV and 10-kV dc Insulation Resistance Testers
Display
Power Supply
Test Voltage
Measurements
Test Types
Other Features
Model Number
Analog/Digital
Line power
Rechargable
10.0 kV
5.0 kV
2.5 kV
1.0 kV
500 V
250 V
10 V steps 50 V to 1 kV
25 V steps 1 kV to max. test voltage
10 V steps 100 V to 2.5 kV,
25 V steps 2.5 kV to max. test voltage
MIT515-US MIT525-US MIT1025-US
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Max. reading 10 TΩ 10 TΩ 20 TΩ
Min. reading 10 kΩ 10 kΩ 10 kΩ
Voltage
Capacitance and time constant
Leakage current
Auto IR
Auto PI
Auto SV
Auto DD
Auto DAR
Ramp test
CAT IV 600 V safety rating
Timer control
Timer display
3mA test currents
USB output (cable included)
RS232 output (cable included)
Calibration certificate included
IP65 rating
Alarm limit mode
Compatible with PowerDB
User programmable lock voltage range
Temp. recording (manual entry)
Real time clock
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Battery charge time (hours) 2.5 2.5 2.5
Noise rejection 3mA 3mA 3mA
Guard terminal performance 2% error guarding 500 kΩ leakage with a 100 MΩ load
Model MIT1025 Panel
MIT515, MIT525, MIT1025
5-kV and 10-kV dc Insulation Resistance Testers
MIT515, MIT525, MIT1025
5-kV and 10-kV dc Insulation Resistance Testers
These unique features improve insulation testing efficiency and effectiveness
High quality flexible silicon insulated test leads
Large backlit LCD shows multiple
parameters simultaneously.
with test clips meet IEC 61010. (Large clips shown.)
Easy-to-read rotary test
selection button includes
IR, IR(t), DAR, PI, DD, SV and
Ramp Test
CATIV 600V rating on ALL terminals
Rotary switch operation for intuitive field use.
ORDERING INFORMATION
Item (Qty) Cat. No.
MIT515-US 1001-936
MIT525-US 1001-940
MIT1025-US 1001-944
Included Accessories
User guide CD
Power lead
3 m leadset x 3, medium insulated clips 1002-531
3 m leadset x 3, large insulated clips
(MIT1025 only) 1002-534
Item (Qty) Cat. No.
Included Accessories (MIT525, MIT1025)
USB cable 25970-041
PowerDB Lite software
Optional Accessories
CB101, 5 kV Calibration Box 6311-077
Calibration Certificate - CB101 1000-113
Control circuit test leads 6220-822
UK
Archcliffe Road, Dover
CT17 9EN England
T +44 (0) 1 304 502101
F +44 (0) 1 304 207342
UKsales@megger.com
UNITED STATES
2621 Van Buren Avenue
Norristown, PA 19403 USA
T 1 866-254-0962 (USA only)
T +1 610-676-8500
F +1 610-676-8625
VFCustomerSupport@megger.com
(case sensitive email address)
OTHER TECHNICAL SALES OFFICES
Dallas USA, College Station USA,
Sydney AUSTRALIA, Täby SWEDEN,
Ontario CANADA, Trappes FRANCE,
Oberursel GERMANY, Aargau
SWITZERLAND, Dubai UAE, Mumbai
INDIA, Johannesburg SOUTH AFRICA,
and Chonburi THAILAND
ISO STATEMENT
Registered to ISO 9001:2000 Reg no. Q 09250
Registered to ISO 14001 Reg no. EMS 61597
MIT515_525_1025_DS_US_V01
www.megger.com
Megger is a registered trademark
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