MODERN MICRO-OHMMETER MIKO-22

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High precision measurements of DC electrical resistance in the range from 0.1 µΩ to 2 Ω with an accuracy of ±0.05%

Modes of resistance measurement start-up

Modes for measuring contact resistance of HV circuit breakers with built-in current transformers (CT)

Adjustable test current up to 200 A

Measurement of DC electrical resistance using the DG method

Measurement of DC electrical resistance using the DCRM method

Comparison of the results obtained

Built-in battery, portability and data transfer

MIKO-22 micro-ohmmeter is based on the time-tested MIKO-21 instrument with significantly expanded features, including modern electrical resistance measurement methods:

Measurement of DC electrical resistance using the DG (Dual Grounding) method.
Measurement of electrical resistance using the DCRM (Dynamic Contact Resistance Measurement) method for the main and arcing contacts of high-voltage circuit breaker poles.

The device is designed to measure DC electrical resistance in the range from 0.1 μΩ to 2 Ω at a current of 200 A and can test:

Main contacts of high-voltage circuit breakers of all types and voltage classes.
Arcing contacts of high-voltage circuit breaker poles.
Contactors, relays, disconnectors, and short-circuiters.
Busbars, various bolted connections, welded joints, and brazed joints.
Elements of equipment for open and closed switchgears in extreme electric and magnetic field conditions.
Components of electrical equipment during high-precision measurements in research laboratories and industrial facilities.

	MIKO-22	MIKO-21	MIKO-10	MIKO-2.3
Test current	200 A	200 A	10 A	1000 A
Resistance range	0.1 μΩ – 2 Ω	0.1 μΩ – 2 Ω	1 μΩ – 0.1 Ω	1 μΩ – 0.1 Ω
Accuracy	±0.05%	±0.05%	±0.2%	±0.2%
Comparison of results with nominal values
DCRM
DG
Removable battery

The instrument supports three modes for starting resistance measurements:

Single – measurement is started once the cable clamps are connected to the tested object and the START button is pressed. The device performs a single measurement and then enters standby mode until the next command is received.
Periodic – used for measurements at predefined intervals. After pressing the START button, the instrument automatically performs measurements according to the selected interval without further user intervention. This mode is particularly useful when the operator's hands are occupied with connecting cables or when monitoring parameter changes over time.
Periodic Circuit – combines automatic activation with periodic measurements when the tested circuit is closed. After pressing the START button, the device waits for the contacts to close before initiating measurements. Measurements continue automatically until the user stops the process.

SKB EP micro-ohmmeters enable contact resistance measurements of both live tank and dead tank circuit breakers using dedicated automatic modes optimized for each application:

CT Eco Mode – enables measurements in circuits equipped with current transformers (CTs) while minimizing battery power consumption. The standard measurement time is approximately 30 seconds.
CT Max Mode – enables measurements in circuits equipped with current transformers (CTs) using a test current of 100 A or 200 A, as selected by the user, without battery-saving restrictions. This mode provides maximum measurement accuracy with a typical measurement time of approximately 15 seconds.

The special automatic measurement modes of the MIKO-22 prevent subjective operator errors, simplify testing procedures, and increase the number of measurements that can be performed on a single battery charge.

MIKO-22 provides quick and convenient selection of test current values up to 200 A. The required test current can be configured using one of the following methods:

Selection from predefined current values: 10 A, 50 A, 100 A, and 200 A.
Selection of the Automatic Test Current mode.
Selection of the Manual Test Current mode, allowing current adjustment from 1 A to 200 A with a resolution of 1 A.

This flexible approach allows measurements to be quickly adapted to the requirements of a specific application, ensuring both efficiency and accuracy during testing.

The DG (Dual Grounding) method is designed for measuring the resistance of parallel conductive paths. Such paths are typically present when a high-voltage circuit breaker is disconnected and grounded on both sides to ensure personnel safety during maintenance work.

When conventional micro-ohmmeters are used to measure contact resistance, one side of the circuit breaker must be disconnected from ground, which reduces operational safety. The DG method enables resistance measurements to be performed without removing the grounding connection, ensuring both safe and accurate testing.

The DG method utilizes an additional measurement channel with current clamps to determine the current flowing through a parallel conductive path of the circuit breaker's main contacts.

MIKO-22 is equipped with a DCRM (Dynamic Contact Resistance Measurement) mode that allows the condition of a high-voltage circuit breaker’s contacts to be assessed without disassembly. The method provides effective monitoring of both main and arcing contacts by recording resistance changes during the circuit breaker opening operation.

Additional Features

High-Voltage Circuit Breaker Drive Control – the integrated drive control function simplifies and improves the convenience of DCRM measurements.
Linear and Angular Displacement Measurement – enables mechanical parameters of the circuit breaker to be recorded simultaneously with resistance measurements, allowing evaluation of the remaining arcing contact length.
- Linear displacement range: 1–900 mm
- Angular displacement range: 0.09–360°

The user can add or remove nominal values for the measured object. Once the measured value exceeds the nominal value, the device emits a warning signal and displays an indication that the reading is above/below the set value.

The built-in 100 Wh battery ensures continuous operation without recharging. An optional battery pack allows users to extend the operating time and replace the battery once the main battery has reached the end of its service life.

Special PC software (currently under development) allows users to control the device and transfer measurement results via USB.

Specifications	Value
Resistance range	0.1 µΩ – 2 Ω
Resolution	up to 0.1 µΩ
Accuracy	±0.05%
Mains voltage	90-264 V AC, 47-63 Hz 127-370 V DC
Measuring method	Kelvin type (the 4-wire cable measure scheme)
Test current range	1 – 200 A
Number of digits in the output of the measurement result	5
Time of measurement Single mode CT eco mode CT max mode DCRM, DG mode	≤2 sec 30 sec 15 sec 2 sec
Battery type	Li-Ion
Battery recharge time	<2 hrs
Consumed power, max	30 W during battery charging
Battery lifetime (in continuous operation)	8 hrs
Built-in memory	Cyclic, 100 measurements
PC connection	USB
Display	Color graphic display, touch-screen, 480 x 272 pix
Dimensions	270 x 246 x 124 mm
Weight	8 kg
Environmental protection	IP 67 (with closed lid) IP 40 (with open lid)
Weight of additional accessories (standard set)	2.45 kg
Operating temperature	-25 °C – +55 °C
Warranty period	3 years
Calibration period	2 years
Testing period	3 years
Interface, User manual language	English

Official reviews from customers based on the results of operating SKB EP instruments are available upon request. Please, fill out the form on the website.

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