"Microohmeter" mode: contact resistance measuring at the maximum current of 1,000 А in the range within 1 µOhm ÷ 105 µOhm
This mode is designed for measuring transfer resistances of any switching devices as well as of demountable and nondemountable contact connections in the range within 1 µOhm ÷ 105 µOhm. Moreover, this mode allows considering the availability or absence of current in the measured circuit of transformer.
When measuring transfer resistances of contacts and connections questions regarding the strength of the measuring current arise as in case of dry contacts the result of measurement will be falsely high. That is why the main requirements to microohmeters are the following: provision of quite heavy operating current which allows burning of acidified film forming on contacts and giving significant error at resistance measuring.
MIKO-2.3 surpasses all foreign- and home-produced microohmmeters. The closest foreign analogue microohmeter with the current of 500A has the weight of 7.5 kg and mains supply. At the same time MIKO-2.3 with its weight of only 2.7 kg produces current of 1,000А. It is particularly true about dead-tank circuit breakers of MKP and U type, the contact circuit of which contains up to eight series-connected arcing contacts and two main contacts which means that they are more sensitive to corrosion and repair labour input is bigger due to the great amount of oil in the tank.
MIKO-2.3 complies with the international standard IEC 60694 "Common specifications for high-voltage switchgear and controlgear standards" (International Electrotechnical Commission (IEC)), specifying current strength for microohmmeters from 50А to the nominal current of the measured item which excludes erroneous diagnostics results.
The instrument has an archive for storing the results of measurements in "microohmmeter" mode; meant for storing of 62 measuring results. For each measurement the value of resistance, current strength and measurement date/time are stored in the archive.
Data transmission to the computer and filing of measurement results is performed with the help of a special program developed by the manufacturer.
