Milli-ohmmeter MIKO-8M(A) with integrated check of OLTCs

Certificates

  • Safety Test Certificate IEC 61010-1:2001
  • Conformity certificate with safety requirements EC/EU
  • Russian State Register Certificates
  • Declaration of Conformity of the Customs Union

Resistance measurement in inductive and non-inductive circuits in the range of 1 μΩ - 10 kΩ

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Automatic setting and systematization of measurement results

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High precision measurement modes

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Various auto calculations and non-volatile memory

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Non-demountable estimation of the OLTCs (DRM test)

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High level of protection and safety conformity

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Touch screen, remote control and bluetooth data transfer

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Variable instrument configuration

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Two modifications of the instrument with different types of power supply

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MIKO-8M(A) milli-ohmmeter is developed to measure DC resistance in the range of 1 µΩ - 10 kΩ with test current up to 10А of:

  • Windings of power and instrument transformers, windings of electric motors, generators, linear compensators and windings of other high-inductive equipment;
  • Contacts of circuit breakers, resistors, buses and other non-inductive circuits;
  • Compensatory, current limiting and other resistors of high-voltage circuit bre­akers;
  • Сables.

Test current range is specified both in automatic and manual modes; resistance measurement range is set automatically. The instrument ensures fully automated resistance measurement under highly inductive load and thermal EMF balancing in external circuit.

Watch detailed video-reviews about MIKO-8M(A) milli-ohmmeter up above or on our YouTube. Watch videos and subscribe.

MIKO-8M(A) implements specialized measurement modes for various configurations of 11 objects (resistive object, inductive object, voltage transformer, current transformer and power transformer, generator, electric motor, reactor, compensator, connection filter and magnet), taking into account their specific features, while the user can select a standard object from the list, or create his own object.

The instrument automatically takes into account the configuration of the object to adjust the measuring modes.

Depending on the object type, you can sel­ect special measurement modes. For example, for a resistive object:

  • AUTO: the measurement starts automatically by the circuit closing.
  • SINGLE: the measurement starts upon the user's command (by pressing the START button).
  • PERIOD: the measurement starts automatically in prespecified time intervals.

For an inductive object, the user can also select one of two modes:

  • MANUAL: start and stop of the measurement are conducted manually by pressing the START button.
  • AUTO 1Ph: the measurement is initiated by pressing the START button and stopped automatically, if criterium specified is reached.

AUTO 1Ph mode has SKB EP patented automatic measurement method that guarantees results with the highest accuracy.

It is achieved by setting the max test current in the measurement circuit not on a staggered basis (depending on the value of the measured resistance), but continuously w/o fixed measurement ranges in a wide load range.

This measurement mode provides high signal level in a complex electromagnetic environment of industrial production or substation. Moreover, in AUTO modes of the measurement process the instrument produces the highest test current that enables guaranteed saturation of the transformer magnetic system.

MIKO-8M(A) has a built-in archive of up to 1,000 measurements for viewing, copying or deleting data. And due to the possibility of choosing an object at the measurement stage, the results are presented more systematically. This feature facilitates interaction with the archive.

The group of MIKO-7M(A), MIKO-8M(A) and MIKO-9(A) instruments has a number of automatic recalculation functions:

  • Auto δ calculation of Rphase between one another.
  • Auto conversion of Rlinear to Rphase. Linear windings are Delta or Star without neutral connected.
  • Auto correction of R measured at to R at t°p taking into account the winding material.
  • Auto δ calculation between Rcorrected and Rp.
  • Auto calculation of by its R.

OLTC non-demountable check mode allows the user to assess the state of the switching OLTC equipment with current limiting resistors without removing contactor tank cover.

This mode involves measuring of instant test current values. Test current firstly passes through the transformer winding and then through OLTC contacts while switching from one tap to another. The DRM graph is built on the basis of the measurement results and shows current change during tap changing. This graph enables to check tap changing time and general object state.

Analysis of the acquired graphs enables not only to sort out OLTC by fault-free/faulty criteria, but also to define the nature of the defect eliminating the opening of fault-free OLTCs. Milli-ohmmeter mode and DRM test complement each other and provide the user comprehensive information about the transformer state.

MIKO-8М(A) has the safety certificate IEC 61010-1. The instrument also meets the requirements of electromagnetic compatibility that are applied to class A instruments according to IEC 61326-1.

The instrument has a high degree of protection against:

  • test cable or mains cable breakdown;
  • excess of test current;
  • EMF of self-induction;
  • overheat of the test block.

At disconnection of the test cable from transformer bushings or from the instrument as well as at disconnection of the mains cable from the mains in the course of measurement, EMF of self-induction of up to several kV is generated in the disconnected circuit and the electric arc appears in the break point.

MIKO-8М(A) is characterized by the redundant protection against EMF of self-induction in case of involuntary disconnection of the test cable or mains cable protecting users from electric shock and the instrument from being damaged.

MIKO-8M(A) is equipped with a color graphic touch screen display of high brightness and an intuitive interface, which facilitates interaction with the device.

Management can be carried out through the keyboard, touch screen or from a special mobile application that allows you to maintain and synchronize the enterprise measurement database from the instrument, and also makes it possible to control the device remotely.

None of the test cables is included to the standard complete set of MIKO-8M(A) device. This allows the customer to choose exactly required cables.

For user's choice and the convenience of connecting to the object, there are special test cables designed of different lengths and different types of clamps/fasteners:

  • 10A Kelvin Clamp test cable 1 x 8.5 m (jaw up to 80 mm);
  • 10A Kelvin C-clamp test cable 1 x 8.5 m (jaw up to 103 mm) for connection to transformer;
  • 10A Kelvin Clamp test cable 1 x 4 m (jaw up to 25 mm) for resistance measurement of CT and VT windings;
  • 10A Kelvin test cable 1 x 3 m (0.5 kg) with 2 probes and 4 crocodile clips (jaw up to 25 mm) (length: 70 mm, plug: 3 mm) for contact resistance measurement of CT and VT contact joints and windings.

For customer’s choice the MIKO-8M milli-ohmmeter has two modifications: with a built-in battery (MIKO-8MA) and without a built-in battery (MIKO-8M). The device can also be powered from the mains (AC 90-253 V, 47-63 Hz // DC 127-354 V).

Specifications Value
Resistance range 1 μΩ - 10 kΩ
Resolution capability 0.1 μΩ
Accuracy ±(0.1%+0.5 μΩ)
Test current output 0,001 A - 10 A
Test current range in DRM mode 0.1 A - 10 A
Measurement display resolution 5 digits
MIKO-8MA: Power supply (built-in battery) Li-ion battery
MIKO-8MA: Battery charge time 3 hours
MIKO-8MA: Battery runtime (in continuous operation) with output capacity 1W 8 hours
Built-in memory up to 1,000 measurements
PC connection USB cable and Bluetooth
Display Color graphic TFT touch, 800 x 480 pixels
Power consumption 120 W
Output capacity, W 60 W
Power supply (mains voltage) AC 90-253 V, 47-63 Hz
DC 127-354 V
Dimensions 270 х 250 х 130 mm
MIKO-8MA: Main instrument weight with battery 4.0 kg
MIKO-8M: Main instrument weight without battery 2.7 kg
Operating temperature range -20ºС - +55ºС
Environmental protection with open cover IP40
Environmental protection with closed cover IP67
Interface and user manual language English
Testing period 3 years
Calibration period 3 years
Warranty period 3 years

Standard complete set

Photo Item, Index Application
MIKO-8M or MIKO-8MA<br>main instrument
  • MIKO-8M or MIKO-8MA
    main instrument
  • SKB049.00.00.000
    or SKB049.00.00.000-01
  • MIKO-8M or MIKO-8MA
    main instrument
  • SKB049.00.00.000
    or SKB049.00.00.000-01

Instrument and documents: User Manual and a Log Book.

Test cables <br><b>on order</b>
  • Test cables
    on order
  • Test cables
    on order

As a matter of convenience for the user, test cables are not included to the standard complete set. Each user can select a cable to his/her own requirements. Please, select at least one test cable (see "additional complete set on order" below).

Mains cable
  • Mains cable
  • SKB018.09.00.000
  • Mains cable
  • SKB018.09.00.000

Mains cable 1 x 2 m. Weight 0.24 kg.
For connecting the instrument to the power line. Temperature range -25°С - +120°С. Rubber insulation.

Ground cable
  • Ground cable
  • SKB010.01.00.000
  • Ground cable
  • SKB010.01.00.000

Ground cable 1 x 2 m. Weight 0.08 kg.
For instrument grounding. The cable is equipped with a ground clamp and a screw end cap. Nominal test current – 50А.

Zero resistance standard
  • Zero resistance standard
  • SKB023.15.00.000
  • Zero resistance standard
  • SKB023.15.00.000

Resistance zero point accuracy check. Value – 0.000 µOhm.

Shunt
  • Shunt
  • Shunt

Type: 75ShSM M3 (75ШСМ М3). For checking MIKO-8M(A) operability. Value – 1 mΩ ±0.5%.

Fuses
  • Fuses
  • Fuses

Type: VP2B-1V-2A (ВП2Б-1В-2А) (2 pcs). For the power source protection.

USB 2.0 A-B Cable
  • USB 2.0 A-B Cable
  • USB 2.0 A-B Cable

USB cable 1 x 1.8 m. For computer connection and data transfer.

Attachment devices set kit
  • Attachment devices set kit
  • SKB126.06.02.000
  • Attachment devices set kit
  • SKB126.06.02.000

Additional complete set (on order)

Photo Item, Index Application
Test cable
  • Test cable
  • SKB041.18.00.000
  • Test cable
  • SKB041.18.00.000

10A Kelvin Clamp test cable 1 x 8.5 m (jaw up to 80 mm). Weight 1.72 kg.
Elastic silicone tube resistant to low and high temperatures and corrosive media.

Test cable
  • Test cable
  • SKB041.22.00.000
  • Test cable
  • SKB041.22.00.000

10A Kelvin Clamp test cable 1 x 8.5 m (jaw up to 80 mm) for connection to transformer bushings. Modification of the SKB041.18.00.000 cable. To be used on transformers with bushings located close to each other. Weight 1.72 kg. Elastic silicone tube resistant to low and high temperatures, and corrosive media.

Test cable
  • Test cable
  • SKB041.26.00.000
  • Test cable
  • SKB041.26.00.000

10A Kelvin C-clamp test cable 1 x 8.5 m (jaw up to 103 mm) for connection to transformer. Weight 2.26 kg.
Alternative version of SKB041.18.00.000 test cable. Elastic silicone tube resistant to low and high temperatures and corrosive media.

Test cable
  • Test cable
  • SKB041.19.00.000
  • Test cable
  • SKB041.19.00.000

10A Kelvin test cable 1 x 3 m. Weight 0.5 kg.
With 2 probes and 4 crocodile clips (jaw up to 25 mm) (length: 70 mm, plug: 3 mm) for contact resistance measurement of CT and VT contact joints and windings.

Test cables for CT and VT
  • Test cables for CT and VT
  • SKB041.21.00.000
  • Test cables for CT and VT
  • SKB041.21.00.000

10A Kelvin Clamp test cable 1 x 4 m (jaw up to 25 mm) for resistance measurement of CT and VT windings. Weight 0.61 kg.
Cable is used for CTs and VTs which are stand-alone or built into transformers / circuit breakers.

Test cable extension
  • Test cable extension
  • SKB031.20.00.000
  • Test cable extension
  • SKB031.20.00.000

Extension cable 1 x 6.5 m. Weight 1.18 kg.
Elastic silicone tube resistant to low and high temperatures and corrosive media. To be used together with test cables SKB041.18.00.000 (jaw up to 80 mm) and SKB041.26.00.000 (jaw up to 103 mm).

Short-circuiting cable (set of 3 pcs.)
  • Short-circuiting cable (set of 3 pcs.)
  • SKB035.31.00.000
  • Short-circuiting cable (set of 3 pcs.)
  • SKB035.31.00.000

Short-circuiting cable set 3 x 12 m with crocodile clips (jaw up to 50 mm). Set weight 0.8 kg (0.27 kg + 0.27 kg + 0.27 kg).

The set is used for applying the DRM-test by short-circuiting secondary circuits. This cable is for OLTCs of power and auto transformers.

Short-circuiting cable (set of 3 pcs.)
  • Short-circuiting cable (set of 3 pcs.)
  • SKB041.23.00.000
  • Short-circuiting cable (set of 3 pcs.)
  • SKB041.23.00.000

Short-circuiting cable set 3 x 3 m with crocodile clips (jaw up to 80 mm). Set weight 1.89 kg (0.63 kg + 0.63 kg + 0.63 kg).

The set is used for applying the DRM-test by short-circuiting secondary circuits. This cable is for OLTCs of power transformers.
Furthermore, this cable is needed for connecting the high-voltage and low-voltage windings when 2 windings mode is applied.

Additional resistor
  • Additional resistor
  • SKB032.25.00.000
  • Additional resistor
  • SKB032.25.00.000

For in-place OLTCs monitoring at total resistance of the winding of no more than 0.5 Ω.
Length 0.11 m + 0.35 m. Weight 0.23 kg.

Tool bag
  • Tool bag
  • SKB126.06.00.000
  • Tool bag
  • SKB126.06.00.000

Convenient, robust, wear proof bag for transportation of cables, documentation and other accessories to the MIKO-8M or to the MIKO-8MA instrument.

Adapter for a reference coil
  • Adapter for a reference coil
  • SKB023.12.00.000
  • Adapter for a reference coil
  • SKB023.12.00.000

For testing laboratories: inspection / calibration of the instrument.
Length 0.025 m + 0.16 m. Weight 0.04 kg.

Manipulating rod
  • Manipulating rod
  • SKB010.41.00.000
    SKB010.41.00.000-01
    SKB010.41.00.000-02
  • Manipulating rod
  • SKB010.41.00.000
    SKB010.41.00.000-01
    SKB010.41.00.000-02

Manipulating rod is designed for test cables connection from the ground or from the tank cover to the bushings of high-voltage circuit breakers, and to the structural elements of high-voltage disconnecting switches and earthing devices, without the use of ladders or elevated platforms.

The rod is completed with Kelvin clamps with current and potential contacts connected by the measurement pad. Test cables are connected to the pad from the ground or a tank cover.

Test cable
  • Test cable
  • 041.28.00.000
  • Test cable
  • 041.28.00.000

10A Kelvin test cable 1 x 2.5 m with spring-loaded probes. To be used for electrical resistance measurement in hard-to-reach places.

  • Open Original

    Urengoy branch of Gazprom Energo, LLC

    Since 2017 Electrotechnical laboratory of the Urengoy branch of Gazprom Energo, LLC has been operating MIKO-10 and MIKO-21 micro-ohmmeters and also MIKO-8M(A) milli-ohmmeter. These devices are used to measure the resistance of switching devices, power and measuring transformers, and electric motors.

    The advantages of the operated devices include small dimensions and weight, the presence of built-in power sources in MIKO-10 and MIKO-21 micro-ohmmeters, a simple and intuitive interface.

    [Manufacturer note]: MIKO-8M(A) milli-ohmmeter also has a built-in power supply. It can be supplied both without a battery: MIKO-8M version, and with it: MIKO-8MA version.

    During the operation, all devices have proven themselves on the good side, there are no malfunctions or failures. In comparison with the previous versions of measuring devices, MIKO-10, MIKO-21 and MIKO-8M(A) have become more efficient, which allows, in addition to the high accuracy of the measurements obtained, to reduce the work time due to the simpler assembly of the measurement circuit.

  • Open Original

    Condensate Stabilization Plant named after V.S. Chernomyrdin (Surgut CSP) the branch of Gazprom Pererabotka, LLC

    Our plant has been using MIKO-8 milliohmmeter since 2016. The device is built into a good strong case that is convenient for transportation. During the time of use, with the help of MIKO-8 were diagnosed more than 100 units of electrical equipment (transformers, electric motors of various capacities and other equipment). One of the main advantages for our staff was the ability of automatic recalculations of deviations with indication of parameters and their saving into the device memory. The second advantage is the possibility of further processing of measurement results on a PC using specialized software. Also, among the advantages we can highlight the measurement speed, intuitive operation of the device, and its small dimensions.

    Among the disadvantages, we note the use of non-standard connectors on the test cables and the inability to use third-party cables, the lack of auto power selection of the device.

    [Manufacturer note]: Cable connectors that are implemented in our devices actually involve the use of the cables only of our production. Thereby we guarantee the reliability of the devices that you use, and we are responsible for the results that you get during measurement process. Unfortunately, when using third-party cables, we cannot guarantee the correctness of the data obtained.
    The possibility of auto power selection is implemented in the upgraded versions of our milliohmmeters, more information about their characteristics can be found via the link. In addition, in modern milliohmmeters, the power can be set both automatically and manually.

    MIKO-8 copes well with the assigned tasks. We can recommend it to other companies.

    We allow you to post this review on the website and to use it for advertising purposes.

  • Open Original

    MegionEnergoNeft, LLC

    In May 2018, MegionEnergoNeft LLC received a pilot operation of the MIKO-8 device for measuring the direct current resistance of windings of oil and dry transformers from 0.4 to 110 kV of various types and designs. The device was operated both during the repair of electrical equipment during the repair of power transformers, and at transformer substations in the course of acceptance tests of electrical equipment serviced by MegionEnergoNeft LLC.

    During exploitation, the advantages of the instrument were revealed, for example: small dimensions, a convenient housing for transportation and operation, an intuitive menu, a built-in measurement archive that allows you to speed up the measurement, simplify the processing of the results and automatically recalculate the data. Measurements are carried out in a short time, which in comparison with other devices significantly reduces the time of measurements. A positive feature of MIKO-8 is the ability to measure the resistance of the windings of power transformers with on-load tap-changers without disconnecting the device from the network and the equipment being measured, which significantly reduces the time it takes to take measurements.

    Information is displayed on a large contrast screen that allows readings without voltage. During operation, no shortcomings were detected, the device works flawlessly.

    As wishes for additional equipment, there is not enough portable compact battery pack with a built-in charger and a plug for connecting in the field [Manufacturer comment: The MIKO-8 millimeter is discontinued – in its place is a new modification of the MIKO-8M / MIKO-8M(A) (with built-in battery)].

    According to the results of trial operation, it was found that this instrument meets the declared characteristics and significantly superior to instrument of a similar purpo

  • Open Original

    Slutsk Electric Networks (RUE Minskenergo)

    We have been operating MIKO-8M(A) milliohmmeter for two years, and the advantages of the device are the following:

    • portability;
    • compact size;
    • informative menu;
    • availability of the DRM test;
    • possibility of use on high-inductive equipment.

    The disadvantage is a small internal memory for information storing.

    MIKO-8M(A) milliohmmeter deserves a high rating according to its characteristics. We are looking forward to new developments.

  • Open Original

    TESS Siberia, LLC

    We have been using MIKO-8M(A) for two months. And the following positive advantages were revealed during the operation process:

    1. Built-in rechargeable battery allows to make measurements without connecting the device to the network.
    2. Checking the continuity of the measurement circuit of the object allows you to make sure that the device is connected correctly.
    3. The presence of the multi-touch screen and buttons ensures reliable control of the device.
    4. Extended resistance range up to 10 kΩ (comparing to MIKO-7) allows to measure resistance of the voltage transformer windings.
    5. The presence of the archive ensures convenient processing of the numerous measurement results in various objects.

    Revealed remarks:

    1. The inscription "Measurement in progress, do not break the circuit" is too small, hardly noticeable in sunlight (it is worth increasing the font of all inscriptions).
    2. It is necessary to increase the volume of the sound signal, because in conditions of heightened noise level it is not audible (in MIKO-7 the sound signal is much stronger).
    3. For the convenience of typing on the keyboard, please add a virtual QWERTY keyboard.
  • Open Original

    Branch "Gusinoozyorskaya SDPP" JSC "Inter RAO – Electric Power Plants"

    Our company has been using MIKO-8M ohmmeter since 2018.

    The device is built into a good robust case that is convenient for transportation in the extreme conditions of Russian roads. Device is equipped with comfortable-to-use control via buttons and multi-touch screen. The key point when choosing a device was the upper board of resistance range, as we are faced with the measurements of voltage transformers, and the price. MIKO-8M seemed to be an ideal choice. One more advantage is that test cables are not included to the complete set of the device because we were able to choose the most suitable one and not to overpay for cables that we would not use in our work.

    The device is doing well with the assigned tasks:

    1. resistance measurements of voltage transformers 15-220 kV;
    2. resistance measurements of generators and electric motors windings;
    3. winding resistance measurements of power transformers 6-220kV.

    We would like to recommend MIKO-8M(A) milliohmmeter to other companies that are involved in the energy industry.

  • Open Original

    Nevinnomysskaya RHPP the branch of Enel Russia, PJSC

    Our company has been using MIKO-8M milliohmmeter since 2019.

    The device is built into a good robust case. It is convenient in working process on production sites. Device is convenient to be operated via buttons or touch screen. An important point when choosing the device was that the measured transformer winding was quite quickly saturated and the EMF appeared was balanced. Previously we have been using Vitok ohmmeter, but it significantly inferiors in the above-mentioned parameters to the MIKO-8M milliohmmeter. Several more advantages are the upper range of the resistance measurement, as we have to deal with the measurements of voltage transformers, and the price. The correlation of all the requirements and possibilities turned out to be the most optimal with MIKO-8M. One more advantage of this device is that none of the measurement cables is included to the complete set of the device. We were able to choose the most suitable one for us and not to overpay for cables that we would not use in our work.

    The device copes with the assigned tasks very well (DC resistance measurement of the windings of power, tapped, auxiliary, voltage transformers). We could definitely recommend it for other companies in the energy industry.

  • Open Original

    Omskenergo the branch of Rosseti Siberia, PJSC

    With the following review we would like to tell you about the experience of use of the devices manufactured by Russian company SKB EP, LLC. We have been working with MIKO-8, MIKO-9A and PKV/M6N in Omskenergo the branch of Rosseti Siberia, PJSC.

    MIKO-8 and MIKO-9A milliohmmeters have proven themselves well during DC resistance measurements of the windings of power and measuring transformers up to 110 kV inclusive, both in the lab and in the field. PKV/M6N circuit breaker analyzer allows to control the required time, travel and speed parameters of moving parts of oil, vacuum, SF6, and electromagnetic circuit breakers 6-10 kV.

    No malfunctions were found during the use of the above-mentioned devices.

    S.V.Kapitonov
    Deputy Director for technical issues -
    Chief Engineer

  • Open Original

    Kurskenergo the branch of Rosseti Centre, PJSC

    2 measurement devices manufactured by SKB EP, LLC are used in the Western section of the diagnostics service of Kurskenergo the branch of Rosseti Centre, PJSC: PKR-2M transformer OLTC analyzer and MIKO-8M milliohmmeter. PKR-2M device has been used since 2018, and MIKO-8M device has been used since 2019.

    These devices are used for diagnostics of power and measuring transformers of voltage 110, 35, 10 kV (MIKO-8M) and OLTCs of power transformers of 110, 35 kV (PKR-2M).

    In practice, both devices have proven themselves from the best side: compact, robust case, convenient and easy-to-use interface, the ability to select the necessary schemes and groups of winding connection. The ability to create and maintain an archive, including the ability to enter factory test data that allows you to carry out the primary analysis of diagnostics results directly at the workplace. High-quality of test cables and clamps, the possibility of adjusting the scope of the complete set. All this greatly reduces the time and labor costs when carrying out equipment diagnostics in comparison with the previously used fleet of devices. It should also be noted that there is software for analyzing and storing diagnostics results on a PC. Furthermore, there is the ability to obtain the necessary information or consultation directly from the device developers.

    The use of PKR-2M and MIKO-8M devices manufactured by SKB EP, LLC brought the diagnostics of power and measuring transformers to a new, higher quality level.

    PKR-2M and MIKO-8M devices manufactured by SKB EP, LLC are recommended to be used by enterprises and companies engaged in the repair and diagnostics of power and measuring transformers.

    I.V. Shirlin
    Head of the Western Section of the Diagnostics Service

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