Complex Tests of MIKO-9 Milliohmmeter

Development of  new version of the MIKO-9 milliohmmeter is currently at a stage that needs different tests and trials.  The instrument was subjected to a full set of tests at ТМН-10000/35-72У1 transformer including in the DRM mode for OLTC devices and in the demagnetization mode at current temperature of -22ºС.

The instrument is designed for measuring the AC electric resistance in the inductance and inductance-free circuits in the range from 10 mkOhm ÷ 30 kOhm on currents of up to 10A for: windings of power, current and voltage transformers; electric magnets and electric motors; resistors of high-voltage circuit-breakers; transient resistance of contacts and contact-type connections of power and signal circuits, and of cables.

MIKO-9 is connected to terminals of transformers and other objects via four types of cables (selected by the user); for operation in the mode of DRM-test of OLTC devices one of the cable sets shall be ordered for short-circuiting and closing the secondary circuits.

Demagnetization mode is intended for eliminating the residual magnetization of transformer's magnetic conduit after DС tests prior to other tests such as idle run, short circuit, measurement of the conversion ratio, etc. MIKO-9 ensures demagnetization of power transformer’s core as per requirements of GOST 3484.1 in either fully automated or manual modes with specifying the demagnetization current increment and limits.

Reference to video at SKB EP portal of Youtube: https://youtu.be/f9i5bRV7YMo

Main functional differences of MIKO-9 from previous analogous devices are as follows:

• Simultaneous connection to three transformer phases and measurement with automatic switch-over;
• Availability of a mode for measuring the resistance on two windings simultaneously, which ensures fast and accurate measurements (for example, by triangle-type connection of secondary windings) when conventional methods do not provide reliable results;
• Transformer’s magnetic system demagnetization mode for eliminating the residual magnetization of a magnetic core after DС tests prior to other tests;
• An in-built ‘heat test’ mode or cooling test mode that correspond to requirements in Item 2.GOST 3484.2-88 "Power Transformers. Heat Tests";
• Independent power supply and a big sensor screen. 

Each device is subjected to routine tests by SKB EP specialists to reveal changes in the product that may deteriorate the safety level. Such tests constitute a certain minimum that is considered to be necessary to take into account all the safety aspects.

The instrument is currently under tests and pilot operation for being entered into the RF State Registrar of Measurement Instruments. Its manufacture is planned for the second quarter of 2018. Orders are accepted.