Advanced Precision Milli-Ohmmeter MIKO-9A

MIKO-9A milli-ohmmeter is developed to measure DC resistance in the range 1 µOhm – 30 kOhm with test current up to 10 А for: Windings of power and measurement transformers, windings of electric motors, generators, linear compensators and windings of other high-inductance equipment; Contacts of circuit breakers, resistors, buses and other inductance-free circuit; Equalizing, current limiting and other resistors of high-voltage circuit bre­akers; Сables.


The instrument is designed to measure the DC
resistance in inductive and non-inductive circuits
in the range of 1 µΩ – 30 kΩ, as well as to generate
oscillograms of a switching contactor in the high-
speed OLTC; it also provides for demagnetization
and “Heat Run Test”.
MIKO-9A, similar to MIKO-8M(A), has a number of
automatic calculation functions for resistance
measurement results.

Key Features

MIKO-9A features specialized measurement
modes for different configurations of 10 objects,
taking into account their specific features. This
functionality enables the user to organize the
results of measurements, and to improve
Workflow with the saved information.
The device features an additional mode of
transformer diagnostics, the “Heat Run Test”,
which is performed by continuous measurement
and periodic result saving of the transformer
winding resistance (recalculated to temperature)
during the cooling process of the winding, and
dependence of the winding temperature on time
can be represented in a tabular or graphical form.


Special mode AUTO 3ph allows simultaneous connection to three phases of the transformer and measurement with automatic switching between phases. This mode reduces the amount of reconnecting to/from the object under test.


OLTC in-place check mode allows the user to assess the state of the switching OLTC equipment with current limiting resistors without removing contactor tank cover (DRM – Dynamic Resistance Measurement method).

Resistance Measurement

The instrument is capable of simultaneous resistance measurement across 2 windings, which guarantees fast and accurate DC resistance measurement of power transformers with delta connected secondary windings, when conventional methods do not guarantee reliable results.

Variable instrument configuration

Depending on the type of object, user can select
special measurement modes. For a resistive
object, the modes are completely similar to MIKO-
8M(A), and for an inductive object, in addition to
the two modes MANUAL and AUTO 1ph, user can
Select AUTO 3ph.
The demagnetization process is compulsory before
open-circuit test, short-circuit loss measurement,
transformation ratio measurement, etc., so the
innovative MIKO-9A has this functionality, and the
graph of current behaviour is displayed on the
instrument in real-time.


1 μΩ – 30 kΩ

0.1 μΩ

±(0.1%+0.5 μΩ)

0.0005 – 10 A

Lithium-ion battery

to 1 000 measurements

USB, Bluetooth

TFT color graphic
touch, 800 x 480 pixels

60 W

~ 90-253 V, 47-63 Hz
= 127-354 V

270 x 250 x 130 mm

IP 67 (device cover closed)

IP 40 (device cover open)

from -20°C to +55°C