Winding Ohmmeter DV Power RMO30TW
SKU: RMO30TW-EU-R1
The RMO30TW device is specifically designed for measuring the resistance of both inductive and non-inductive loads. It is built to comply with the safety standard IEC 61010-1, ensuring safe operation during testing procedures. Furthermore, it fulfills the requirements set forth by IEC 60076, which specifies the standards for power transformers.
- Test current 5 mA – 30 A
- Open voltage up to 55 V
- Measuring range 0,1 µΩ – 100 kΩ
- Typical accuracy ± (0,1 % rdg + 0,1 % FS)
Estimated shipping time 4-5 weeks
The RMO30TW device is specifically designed for measuring the resistance of both inductive and non-inductive loads. It is built to comply with the safety standard IEC 61010-1, ensuring safe operation during testing procedures. Furthermore, it fulfills the requirements set forth by IEC 60076, which specifies the standards for power transformers.
- Test current 5 mA – 30 A
- Open voltage up to 55 V
- Measuring range 0,1 µΩ – 100 kΩ
- Typical accuracy ± (0,1 % rdg + 0,1 % FS)
Intended Use
The winding resistance tester, DV Power RMO30TW, finds typical applications in measuring the resistance of inductive test objects and analyzing on-load tap changers in the electric power industry and similar sectors. It is particularly well-suited for testing the windings of various transformers such as power transformers, distribution transformers, and autotransformers. Additionally, it serves as a valuable tool for verifying on-load tap changers and performing transformer demagnetization.The DV Power RMO30TW transformer winding ohmmeter is employed in various scenarios including resistance measurement during manufacturing, commissioning, and testing of:
- Transformers
- On-load tap changers
- De-energized tap changers
- Generators and electrical motors
- High current busbar joints
- Cable splices
How to Use RMO30TW
The RMO30TW is primarily designed for measuring the resistance of transformer windings, and it provides three options for testing: NONE, DETC, and OLTC. When testing the winding resistance of a transformer without a tap changer in the current path, it is recommended to select the NONE option. However, when testing the winding resistance of a transformer with a tap changer in the current path, either DETC or OLTC should be chosen. RMO30TW automatically regulates the injection of current and discharge of energy from the test object.The winding-ohmmeter RMO30TW is a precise measuring tool that generates a true DC ripple-free current. Another useful feature is the delta R function, which indicates the stability of the measurement readings and helps in obtaining accurate results.
RMO30TW Winding-Ohmeter Design
The RMO30TW is a reliable test device that can store up to 1000 measurements in internal memory. Three independent channels enable the testing of three windings in series. A built-in thermal printer is available as an option. Free DV-TR software is included in the purchasing price and communicates with the RMO30TW winding-ohmmeter via USB or RS232 interface. It allows you to run the test remotely from a PC, as well as to download test results, analyze them, and generate fully configurable test reports. A high output voltage (up to 55 V) enables the measurement of a wide resistance range and the use of long and thinner test cables, which is a benefit. As a digital winding-ohmmeter is the ideal choice for industries that require precise and consistent measurement of electrical resistance.Connecting RMO30TW to a Test Object
The RMO30TW device follows Kelvin's (four-point) measurement principle for its connection principle. This principle ensures accurate measurements by using separate "Voltage Sense" terminals attached to one side of the measuring clamps and "Current Cables" attached to the other side of the measuring clamps. The resistance of the current cables and clamps is effectively eliminated from the resistance measurement. This configuration helps to provide precise and reliable resistance readings by minimizing the impact of any additional resistance in the measurement setup.Product information | |
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Product name | Winding Ohmmeter DV Power RMO30TW |
Brand | DV Power |
Country of origin | Sweden; |
Winding Resistance Measurement | |
Test currents | 5 mA – 30 A DC |
Output voltage | up to 55 V DC |
Measurement range | 0,1 μΩ – 100 kΩ |
Mesurement resolution | 0,1 μΩ – 10 Ω |
Typical accuracy | ± (0,1 % rdg + 0,1 % FS) for 0,1 μΩ – 1,999 kΩ range ± (0,2 % rdg + 0,1% FS) for 2 kΩ – 10 kΩ range ± (1.0% rdg + 1.0% F.S.) for 10 kΩ – 100 kΩ range |
OLTC Dynamic Resistance Measurement | |
Sampling rate | 4 ms |
Open circuit detection and warning | Automatic |
Transition current ripple measurement | Yes |
Transition time measurement | Yes |
Temperature Measurement | |
One temperature measurement channel | Thermometer Pt100 class B |
Mesurement range | -50 °C – +180 °C |
Mesurement resolution | 0.1 °C |
Printer (optional) | |
Printer | Thermal printer |
Paper width | 58 mm (2,3 in) |
Power Supply | |
Powered by | Mains power |
Mains power connection according to | IEC/EN60320-1 UL498, CSA 22.2 |
Mains power input voltage | 90 – 264 V AC |
Mains power input frequency | 50/60 Hz |
Input power | 2250 VA |
Data Storage | |
Internal memory positions | 1000 |
Computer Interface | |
Interface v1 | USB (standard) |
Interface v2 | RS232 (optional) |
Display | |
Display v1 | LCD screen with 20 characters by 4 lines |
Display v2 | LCD with backlight |
Environmental Conditions | |
Operating temperature | -20 ºC – +60 ºC (-4 ºF – +140 ºF) |
Storage & transportation | -40 ºC – +70 ºC (-40 ºF – +158 ºF) |
Humidity | 0 % – 95 % relative humidity |
Applicable Standards | |
Installation/overvoltage | CAT II IEC/EN 61010-1 |
Pollution | Degree 2 |
Low voltage directive | Directive 2014/35/EU (CE Conform) |
Electromagnetic compatibility | Directive 2014/30/EU (CE Conform) EN 61326-1 |
Dimensions and Weight | |
Dimensions (W x H x D) | 250 x 198 x 350 mm (9,9 x 7,8 x 13,8 in) |
Weight | 8 kg (17,6 lbs) |
- Cable bag
- Ground (PE) cable
- USB cable
- Current cables 2 x 10 m 10 mm2 and Sense cables 2 x 10 m with TTA clamps
- Current connection cable 1 x 5 m 10 mm2 with TTA clamps
- Mains power cable EU 16 A
- RMO30TW device
- Sense cables 2 x 10 m with TTA clamps
- USB with DV-TR software
- Transport bag for instruments in Metal housing
The DV-Win software enables control and observation of the test process, as well as saving and analyzing the results on a PC. It provides a test report, arranged in a selectable form as an Excel spreadsheet, PDF, Word, or ASCII format. The software provides an OLTC (tap changer) condition assessment through analysis of the graphs representing dynamic resistance values during the tap changer transitions.
Additionally, the DV-Win measures and calculates the OLTC transition time, the ripple and the winding resistance for each tap changing operation.
The software can also perform the calculations necessary for the “Heat Run” test. All results can be exported in the report format.
The standard interface is USB.