TENTECH MD-5075x User manual

Formato: 137mm x 190mm
P. 37
P. 03
Manual de uso
Megóhmetro digital
Digital insulation tester User guide
TENTECH CORPORATION
7330 NW 66th ST - Miami, FL 33166
Phone: [phone] / Fax: [phone]
www.tentech.com
5075x

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MD-5075x
5 kV Insulation tester
User guide
GF-2015RA
©2016 TENTECH.All rights reserved.

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
Safety warnings
•Before to use this instrument the User guide and Safety warnings must be read
and understood.
•Safety procedures and rules for working near high voltage energized systems
must be observed during the use of this equipment. The generated voltages
may be dangerous.
•Do not connect or disconnect the test leads during the measurement.
•Be careful not to make short-circuit between the terminals while a measurement
is running, because it could be dangerous for the operator.
•Be sure that there are not any voltage difference between the points to which the
equipment will be connected to, neither between them and ground.
•The panel, terminals and connectors of the equipment must stay dry and clean.
This equipment should be used only by a trained and competent
person, strictly applying suitable safety rules.
Used symbols
Caution, risk of electric shock.
Caution, refer to User Guide.
Battery
Printer
Capacitance
Voltmeter
Equipment complies with current EU Directives.
The rubbish bin with a line through it means that in the European Union,
the product must undergo selective disposal for the recycling of electric
and electronic material, in compliance with Directive WEEE 2002/96/EC.

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Index
1. Description.........................................................................................................6
2. Panel control functions.......................................................................................7
2.1. Keyboard....................................................................................................8
2.2. Display .....................................................................................................10
3. Charging battery ..............................................................................................11
4. Connecting the MD-5075x ...............................................................................11
5. Use of “Guard” (G) terminal..............................................................................14
6. Setting tests.....................................................................................................15
6.1. Test voltage definition...............................................................................15
6.2. Selection of the operation mode ...............................................................16
6.2.1. Normal mode .....................................................................................16
6.2.2. SVT Mode (step voltage tests) ...........................................................16
6.2.3. “TIMER” Mode....................................................................................18
6.2.4. “Pass / Fail” Test mode......................................................................19
7. How to perform tests........................................................................................20
7.1. Measurement of the Dielectric Absorption Index (DAI)..............................22
7.2. Measurement of the Polarization Index (PI)..............................................23
8. Other functions ................................................................................................24
8.1. Backlight...................................................................................................24
8.2. Filter.........................................................................................................24
8.3. True RMS AC/DC Voltmeter.....................................................................24
8.4. Leakage current measurement.................................................................24
8.5. Capacitance measurement.......................................................................25
8.6. Hold..........................................................................................................25
8.7. Internal memory........................................................................................26
8.8. Battery status check .................................................................................26
8.9. Auto power-off..........................................................................................26
9. Software ..........................................................................................................27
9.1. USB Drivers..............................................................................................27
9.1. T-Logger software ....................................................................................27
10. Printer............................................................................................................28
11. Cleaning ........................................................................................................28
12. Technical specifications.................................................................................29
13. Application note 32 ........................................................................................32
14. Warranty........................................................................................................35

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1. Description
The digital insulation tester model MD-5075x is at the cutting edge of
TENTECH’ insulation analyzer equipment and it is one of the more
complete and sophisticated of the international market. It uses an efficient
well experienced technology, which provides safe, reliable and accurate
measurements of insulation resistances up to 5 TΩ, with 4 pre-selected
test voltages: 500 V -1 kV -2.5 kV -5 kV. Other test voltages may be
selected in steps of 25 V, 100 V, or 500 V.
A microprocessor controls the equipment, making the operation easier
and enabling the incorporation of advanced features such as: Auto-range
selection, Memory enabling storing up to 4000 readings, AC/DC
voltmeter, Polarization and Dielectric absorption index automatic
measurement, Measurement of Leakage Current and Capacitance,
“TIMER” to program resistance test time, “Limit” allowing making test type
“Pass / Fail” with programmable limit. Step Voltage Test, Built-in Printer,
Real Time Clock and Calendar for measurement identification. Built-in
chronometer, indicating elapsed time, in minutes and seconds, since the
test started.
The USB interface enables communication of the equipment with a
computer to transmit registered data. The T-Logger software analyzes the
results and shows through charts and tables, automatically generating the
test protocol. The built-in printer records values on paper every each 15
seconds, as a measurement taken document.
Due to its constructive features, this instrument is strong delivering an
excellent performance both with laboratory and field works, under hard
environment conditions.

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2. Panel control functions
Voltage output terminal (-V)
Zero reference terminal (+R)
Guard (G) Terminal
Display
Keyboard
High Voltage led
On / Off key
USB communication port
Power supply input
Printer

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2.1. Keyboard
Key
Function
LED
Turns the printer on/off
Indicates that the printer
is turned on.
Hold - Freeze the last reading on the display
The Hold function is on
Battery - exhibits the battery charge status
on the display
Indicates that the battery
charger is on
Filter - Activates the filter that minimizes the
interferences of the external noise
Indicates that the filter is
on
Shows the calculated value on the display as
a result of a Step Voltage Test (SVT),
Polarization Index (PI) and Dielectric
Absorption Index (DAI)
–
Backlight - activates the display light
–
Capacitance - exhibit the capacitance value
–
Activated enables the programming of the
Operation Mode (Normal, SVT or with
TIMER of selectable time)
Indicates that the
selection of the
Operation Mode is
enabled

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Activated, enables programming of 25 V
step tests voltages
25 V steps activated
Activated, enables programming of 100 V
step tests voltages
100 V steps activated
Activated, enables programming of 500 V
step tests voltages
500 V steps activated
Selection of 500 V test voltage
Indicates 500 V selected
Selection of 1 kV test voltage
Indicates 1 kV selected
Selection of 2.5 kV test voltage
Indicates 2.5 kV selected
Selection of 5 kV test voltage
Indicates 5 kV selected
These keys (decrease or increase) enable
the selection of the value that is being
programmed.
–
Activates / enables programming of the limit
for the “Pass / Fail” test
Indicates when the
measured resistance is
lower than programmed
limit
Start - Start test
Indicates that the test is
being executed
Stop - End of test
–

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2.2. Display
Measurement results in the corresponding measuring unit, elapsed time
since the measurement started, selected test voltage, analogue indication
by means of a bargraph and several messages to the operator are
displayed on alphanumeric LCD.

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3. Charging battery
The MD-5075x uses a rechargeable LiFePO4 12 V - 6000 mAh.
At the end of battery useful life, the battery must be recycled or
disposed of properly, in order to protect the environment.
Charging procedure:
•Check if the MD-5075x is turned-off and connect it to the mains (AC
adapter).
•The charging indicator ( ) will turn on red and will
remain that way until the battery is totally charged. Then the light will
remain green and keep in that way until the MD-5075x is disconnected
of the mains.
Alternate green and red
lights
Evaluation of the battery initial status when the
source is connected, during one second.
Steady red light
Battery under charge.
Flashing red light
The battery was not successfully charged. It
denotes some trouble in the battery charging
process.
Steady green light
The charge has successfully finished. The battery
is OK.
The rechargeable battery does not have “memory effect” and there are no
restrictions to start charging it as many times as is needed. However the battery
could be da
maged if remains in deep discharge for a while.
To avoid this effect, charge the battery before left the equipment in storage and
don’t let pass more than 30 days without recharge, even if the instrument wasn’t
used (under storage, the battery loses part of its charge).
IMPORTANT: while the equipment is connected to the mains supply the START
key is inhibited, so you will not be able to make measurements.

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4. Connecting the MD-5075x
ATTENTION:
For a safe operation, the proce
dures detailed below should
be carried out with the device Powered-Off.
Please, do check
if
there is no difference of potential voltages between
the points where the
MD-5075x
shall be connected to. Please, check the
same between those points and the ground.
At the time of the conne
ction and power-on
, the equipment automatically
enters in the voltmeter mode and begins to exhibit the circuit voltage in
the display.
The circuit to be tested must be de
-
energized to avoid interferences in the
measurement.
The equipment will block the st
art of measurement if it
detects a
voltage greater than 60 V in the circuit.

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Connect the red cable security terminal to the equipment (-V) output
terminal, the BNC terminal of the black cable to the zero reference (+R)
terminal and the “alligator” terminals to the element to be measured as
indicated in the next figure.
The test leads in the picture are merely illustrative.

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5. Use of “Guard” (G) terminal
Depending on the measurement to be made, the Guard (G) may be used
or not. During the measurements, the equipment should be electrically
grounded to avoid unsteady readings. When insulation is measured
regarding grounding, the Rterminal is connected to earth and the
condition by means of which the equipment potential setting is fulfilled. If
the measurement is performed between two parts, which are not
grounded (for example, between two phase conductors in a three-phase
cable), the equipment GUARD terminal must be grounded. This implies
that whenever a measurement is performed, one of the GUARD or R
terminals must be grounded, but not both of them simultaneously.
Technical Note 32, reproduced at the end of the manual, explains the
usage of GUARD terminal in order to eliminate the parasite resistance
effect over the result of measurements.

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6. Setting tests
The insulation tester MD-5075x is an extremely versatile instrument that
enables automatic performance of several types of insulation tests, and
records them in its internal memory and/or prints the results. Thus, it is
necessary to appropriately define the tests to be performed, setting the
following parameters before starting the measurement: Test voltage, Test
duration for “TIMER” mode test, Maximum Voltage for step voltage test
(SVT) and Minimum resistance limit for “Pass/ Fail” tests.
6.1. Test voltage definition
In order to define the test voltage value, first it is necessary to select one
of voltage adjustment keys: . These keys enable both the
pre-programmed voltage selection ( ) and the and
keys which increase or decrease the value of the step voltage test for
25 V, 100 V or 500 V, depending on the selected voltage adjustment key.
As long as the equipment is on, the voltage adjustment key will be
selected. Please, press again the adjustment key selected at the moment
with the aim of leaving the test voltage selection mode.
Note: Test voltage is the only one parameter that may be modified during
tests.

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6.2. Selection of the operation mode
The MD-5075x insulation tester has four operation modes: Normal, with
“TIMER”, SVT and “Pass / Fail”. The first three modes are selected using
the key; the “Pass/ Fail” test mode is activated pressing key.
6.2.1. Normal mode
The normal mode is used in the resistance measurement with unique
voltage, without time limit. When selected, there are no special indications
in the display.
6.2.2. SVT Mode (step voltage tests)
The use of key allows the MD-5075x setting for the performance of a
step voltage test; when this mode is selected, the display shows the SVT
abbreviation.

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Under this operation mode, the user does not define a specific voltage
test, but a maximum voltage value. The device will start the test applying
a 500 V voltage and increase this value in 500 V steps each minute until
reaching the programmed voltage. At each stage, the MD-5075x
measures the resistance before advancing towards the following step.
The use of voltage adjusting keys, determines the value of the highest
voltage – which will be, in all cases, a multiple of 500 V, up to a 5000 V
limit. It is advisable to use the key in order to select this value;
and keys may be used, but if the selected value is not a multiple of
500, it will be rounded down.
The test result is calculated according to the following formula:
= SVT R
R
V MAX
500
After test ending, the value may be recovered by pressing key.

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6.2.3. “TIMER” Mode
The use of key allows the MD-5075x setting for the performance of a
pre-set - duration test; when this mode is selected, the display shows the
programmed time. Use and keys to define the duration of the
tests in 1 minute, 3 minutes, 10 minutes, 30 minutes or 90 minutes.

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6.2.4. “Pass / Fail” Test mode
Press key in order to determine the lower insulation limit for type
“Pass / Fail” test. Select this value using and keys. Possible
values are 10 MΩ, 100 MΩ, 1 GΩ or 10 GΩ.
During a “Pass/ Fail” test, the MD-5075x will indicate when the insulation
resistance is lower than the programmed limit, both with an intermittent
beep and the key led flashing. The key led will remain flashing
until the end of tests, or until the measurement of the resistance value is
greater than the programmed limit.

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7. How to perform tests
After having set the desired measurement, press
key. The HIGH VOLTAGE indicator w
ill turn
on indicating that the
insulation tester is apply
ing
high voltage to the element under test.
During some seconds the intelligent auto-range system will search for the
most convenient range for the value under measure. At this moment the
display will show the message “WAIT...”.
As soon as the MD-5075x selects the appropriate range, the display will
show the number of test, the selected voltage value, exhibiting the value
of the applied voltage and the leakage current, date and time, will start
counting the elapsed time and the resistance value indication will be
exhibited with its corresponding unit, and the analogue indication will start
by bargraph. In order to end the test, press the key. At that moment,
last measured values will remain frozen in the MD-5075x display. By
pressing the key again, the equipment will return to the voltmeter
function.

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Example:
The display exhibits the test number (12), the measured resistance value
(602 GΩ), the voltage selected of 2500 V, the elapsed time (6:25
minutes), the applied voltage (2.51 kV), the leakage current (4.17 nA),
date and time.
NOTE: If the resistance measured is greater than 5 TΩ @ 5 kV, the
following message will be exhibited:
R > 5TΩ
ATTENTION:
Please, never connect or disconnect the test leads
with the
equipment
under operation or while the High Voltage led is on. If there is
a need to modify
the
connections, this should be done with the equipment
disconnected and with discharged potentials (High Voltage led off)