The instrument measures the electric resistance of windings of power and instrument transformers, of electric motors, electromagnets, etc.
It is an advanced version of MIKO-7 with expanded functions.
It performs diagnosis-in-place of transformer LTC.
It compensates errors due to external thermal emf.
The instrument is supplied with a color graphic display.
MIKO-7 with basic functions - production of the device is discontinued. A new version of MIKO-7M with be delivered to the warehouse in the IV quarter of 2018.
MIKO-7 with advanced functions - production of the device is discontinued. A new version of MIKO-7M with be delivered to the warehouse in the IV quarter of 2018.
| Range of measurement | 10 mkOhm ÷ 10 kOhm | automatic selection of the measurement range. |
| Time of measurement | from 10 sec | time depends on inductance of the measured object. Maximum measurement time on the ОРДЦ-533000/330000 transformer is 7 min 51 sec. |
| Error of electric resistance measurement | ± [0.001R + 0.5] mkOhm | R - measured resistance. |
| Instrument current amperage | 0.0014÷10.0 A | automatic selection of the instrument current range. |
| Instrument current drift | 0.0002 %/sec. | in a minute after the measurements start. |
| Maximum output voltage | 22 V | ensures rapid growth of instrument current in the inductive circuit. |
| Limits of specified output power | 0,3; 1; 5; 20; 62 W |
| Power supply | ||
| network voltage | 100÷242 V
100÷300 V | |
| power voltage from the battery | 11÷14 V | |
| Maximum consumed power | 120 W | |
| Parameters of a instrument block | ||
| L x W x H | 270×250×130 mm | high operating currents at small size. |
| weight | 3,2 kg | |
| Working temperature |
−20 ÷ +40ºС | the instrument is subjected to acceptance tests at a temperature of ambient air from -30 to +50ºС. |
| IP rating of the instrument | ||
| IP for transportation | IP64 | in closed state the instrument can be subjected to different impacts and does not require specific conditions for transportation. |
| IP rating in operating state | IP20 | |
| Rating of protection from current injury | I | instrument current is never exceeded; polarity reversal of cable ends and self-inductance of electromotive force in case of occasional cable disconnection are eliminated. |
| Warranty period | 3 years | |
| Service life | 10 years | |
| Gauging period
The values of variables that determine the milliohmmeter accuracy gradually change during its operation. Gauging implies correction of variables for ensuring the accuracy of readings. | 3 years | |
| Inter-testing period | 3 year | |
Connect the instrument or to the electric network (220 W) or to a battery (12 W)
Simultaneous power supply from the network and the battery is not recommended.
Connect the red clamp of the cable to a plus battery terminal, the black one connect to minus — battery terminal.
Connect the instrument cable to the instrument.
Any end of the instrument cable can be connected to any grounded or non-grounded end of a three-phase winding using any connection diagram in any sequence.
Replacement of three arrows ↓↓↓ by two ↓↓, then by one ↓ means continuous resistance reduction. Hence, the process of resistance identification is normal. If arrows are replaced by an asterisk * the measurement can be stopped.
When data on the current amperage and resistance appear, stop the measurements by pressing «Start/Stop».
Resistance has been identified.
The Table shows the measured resistance and amperage of the instrument current.
Furthermore, the device has automatically computed:
The Table shows the results of measurements for all the three windings.
MIKO-8 has automatically computed:
MIKO-8 additionally computes relative deviations of measured resistances of windings between one another — δR.
Conversion of linear resistances into phase ones shows which winding is damaged. At the moment you see that winding
MIKO-8 the method that allows determination of LTC state without removing the tank cover.
In this mode MIKO-8 checks the state of current-limiting resistors and selector operation, measures time intervals of contactor operation, assesses the state of contact paths of LTC devices.
To go over to the results, press «Start/Stop».
Please keep in mind that when switching over LTC from position 5 into position 6 (similarly, from position 19 to position 20) the amperage considerably falls as compared to other switchings-over. This fact evidences the problem in the fixed contacts.
At no-fault LTC contactor there shall be four points of amperage measurement on the curve, whereas we see only three points. At the section 100,05 — 100,062 sec. the amperage dropped below 0,1 А. Most probably, one of the fixed contacts has burnt over.
This example demonstrates that using MIKO-8 you can find an exact fault location without opening LTC.
To select the measurement, press →.
To review the stored results of measurements, press «Enter».
Please keep in mind that when switching over LTC from position 5 into position 6 (similarly, from position 19 to position 20) the amperage considerably falls as compared to other switchings-over. This fact evidences the problem in the fixed contacts.
To go back to archive, press «Cancel»,
At no-fault LTC contactor there shall be four points of amperage measurement on the curve, whereas we see only three points. At the section 100,05 — 100,062 sec. the amperage dropped below 0,1 А. Most probably, one of the fixed contacts has burnt over.
To select the measurement, press →
To review the stored results of measurements, press «Enter».
The Table shows the results of measurements for all the three windings.
MIKO-8 has automatically computed:
MIKO-8 additionally computes relative deviations of measured resistances of windings between one another — δR.
Conversion of linear resistances into phase ones shows which winding is damaged. At the moment you see that winding A gives higher resistance (Ra=908,41 mΩ).
To go back to archive, press «Cancel».
To select the measurement, press →
Measured resistance and amperage are given below the table. The device additionally computed:
Measurement is in progress
Когда отобразятся данные по силе и сопротивлению тока, остановить измерение нажав «Стоп».
The measurement is over. The readings are shown.
Чтобы испытать прибор методом DRM, нажмите «Пуск»
Чтобы выйти, нажмите «Ввод».
Испытания прибора методом DRM закончено. Отображается результат.
Чтобы выйти, нажмите «Ввод».
Disconnect the instrument from the network
Disconnect the instrument from battery
| Instrument block of MIKO-8 | |
| A set of wires and attachments | |
| SKB031.23.00.000 | Main cable |
| SKB010.01.00.000 | Ground wire |
|
| Shunt 75 ШСМ М3.75-0,5. Rsh=1.0 mOhm
It is designed for expanding the measurement range. Voltage drop at voltage fans at rated current makes 75 mV for all the shunts. |
| Two safety devices ВП2Б-1В-2А | |
| Cable USB 2.0 A→B | |
| SKB023.15.00.000 | Gauging equivalent of zero resistance |
| SKB126.06.02.000 | Bag №2 |
| Documentation | |
| SKB131.00.00.000OM
SKB131.00.00.000TP | Operations Manual
Technical passport Gauging Certificate CD with documentation and software |
Additional accessories (for extra pay) | |
| SKB032.18.00.000
| Instrument cable, 8.5 m
"crocodiles" with jaws opening of up to 37 mm. |
| SKB032.12.00.000
| Instrument cable, 8.5 m
measurement from ground (35 kV), from the transformer cover (35÷500 kV), "crocodiles" with jaws opening of up to 80 mm. |
| SKB032.19.00.000
| Instrument cable, 3 m
resistance measurement following the four-terminal circuit in the inductive and non-inductive circuits. Two probes with red insulation and two probes with black insulation, "crocodiles" A25C. |
| SKB23.21.00.000
SKB23.21.00.000-01 | Potential clip contact
Two items (red and black) for convenient connection to the input studs (for cable SKB032.12.00.00). |
| SKB032.25.00.000 | An additional resistor
For in-place LTC control at full winding resistance below 0.5 Ohm. |
| SKB031.20.00.000 | Extender for instrument cables 6.5 m. |
| SKB031.17.00.000 | Cable for power supply from the battery 5 m. |
| SKB032.13.00.000
SKB032.13.00.000-01 SKB032.13.00.000-02 | Short-circuiting cable (G-cramp G50(2"))
Short-circuiting cable (G-cramp G75 (3'')) Short-circuiting cable (G-cramp G100 (4'')) |
| СКБ126.06.00.000 | A bag for cables and documentation |
Statement of Compliance, 1,2 Mb
