Test & Measurement
Power Analysor
Power Equipment Test

Winding Ohmmeter

  • Product No:RMO-TW Series
  • Manufacturer:IBEKO Power AB (DV-Power)

The Winding Ohmmeter of the RMO-TW series is designed for winding resistance measurement of inductive objects. The RMO-TW instrument is based on the state of the art technology, using the most advanced switch mode technology available today. The RMO-TW instrument is accurate (0,1%), powerful (up to 50 A) and lightweight. It generates a true DC ripple free current with automatically regulated measurement and discharging circuit.


RMO-TW instrument can perform a simple, quick and reliable transformer on-load tap changer verification. This instrument enables measurements of a winding resistance in every tap position of an on-load tap changer without discharging between the tests. Problems with switching of the OLTC, such as interruption, can be detected with these measurements. The results are displayed on a backlit LCD display

  • Three resistance measurement channels 

  • One temperature measurement channel 

  • Accuracy 0,1 % 

  • Lightweight 

  • On-load tap changer verification 

  • Automatic resistance measurement for the Heat Run test 

  • Rapid automatic demagnetization 

  • Automatic discharge circuit 

  • Resistance measurement of transformers, rotary machines and non-inductive objects 

  • Four models: RMO10TW, RMO20TW, RMO30TW, RMO50TW


Winding Resistance Measurement

  • Test currents: 

    ̶ 5 mA – 10 A DC for RMO10TW

    ̶ 5 mA – 20 A DC for RMO20TW

    ̶ 5 mA – 30 A DC for RMO30TW

    ̶ 5 mA – 50 A DC for RMO50TW

  • Output voltage: up to 55 V DC 

  • Measurement range: 0,1 μΩ - 10 kΩ 

  • Typical accuracy:

    ±(0,1% rdg + 0,1% F.S.) for 0,1 μΩ-1,999 kΩ range

    ±(0,2% rdg + 0,1% F.S.) for 2 kΩ - 10 kΩ range

Resolution

  • 0,1 μΩ – 999,9 μΩ: 0,1 μΩ 

  • 1,000 mΩ – 9,999 mΩ: 1 μΩ 

  • 10,00 mΩ – 99,99 mΩ: 10 μΩ 

  • 100,0 mΩ – 999,9 mΩ: 0,1 mΩ 

  • 1,000 Ω – 9,999 Ω: 1 mΩ 

  • 10,00 Ω - 99,99 Ω: 10 mΩ 

  • 100,0 Ω – 999,9 Ω: 0,1 Ω 

  • 1,000 kΩ – 9,999 kΩ: 1 Ω

Data Storage

  • 1 000 internal memory positions

Printer (optional)

  • Thermal printer 

  • Paper width 80 mm

OLTC Dynamic Resistance Measurement

  • Sampling rate: 4 ms 

  • Automatic open circuit detection and warning 

  • Transition current ripple measurement 

  • Transition time measurement using DV-Win  software 

  • Timing measurement of different transition  changes using DV-Win graph analysis tool

Temperature Measurement

  • One temperature measurement channel Thermometer Pt100

    -50 ºC +180 ºC / -58 ºF +356 ºF 

    50 mm x 6 mm    

Computer Interface

  • USB 

  • Optional: RS232

Warranty:  Three years

Environmental Conditions

  • Operating temperature:  - 10 ºC to + 55 ºC / + 14 ºF to + 131 ºF 

  • Storage & transportation:  - 40 ºC to + 70 ºC / - 40 ºF to + 158 ºF 

  • Humidity 5 % - 95 % relative humidity,  non condensing

Dimensions and Weight

  • Device                                       Weight                      Dimensions (WxHxD) 

         RMO10TW /RMO20TW            8 kg / 17.6 lbs           205 x 287 x 410 mm (8.1 x 11.3 x 16.4 in)

         RMO30TW RMO50TW             8.5 kg / 18.7 lbs        205 x 287 x 410 mm (8.1 x 11.3 x 16.4 in)

Mains Power Supply

  • Connection according to IEC/EN60320-1;  UL498, CSA 22.2 

  • Mains supply: 90 V - 264 V AC 

  • Frequency: 50 / 60 Hz 

  • Mains supply voltage fluctuations up to ±10 %   of the nominal voltage 

  • Input power: 2 250 VA 

  • Fuse 15 A / 250 V, type F, not user replaceable

Applicable Standards

  • Installation/overvoltage: category II 

  • Pollution: degree 2 

  • Low voltage directive: Directive 2014/35/EU (CE conform); Applicable standards, for a class I instrument, pollution degree 2, installation category II: IEC EN61010-1 

  • EMC:   Directive 2014/30/EU (CE Conform)     Applicable standard EN 61326-1 

  • Safety: CAN/CSA-C22.2 No. 61010-1, 2nd edition, including Amendment 1


RMO-TW Series
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