Winding Resistance Test

Multi-tap Current and Voltage Transformer Analyser | CVA500

Multi-tap Current and Voltage Transformer Analyser - Overview

The CVA500 combines automated test execution, one-time connection for multi-tap CTs, standard-compliant measurements, and an intuitive 10.1-inch touchscreen interface to help technicians perform tests faster and with greater confidence. From CT saturation and knee point testing up to 2 kV to turns ratio, polarity, winding resistance, insulation resistance, burden testing, and accuracy class assessment, the CVA500 provides advanced functionality for a wide range of instrument transformer testing applications. This analyser is suitable for utilities, service companies, and laboratories that need reliable CT, VT, and CVT testing capabilities in a professional and cost-effective solution.

Multi-tap Current and Voltage Transformer Analyser - Features
- Burden testing for CTs, VTs, and CVTs
- CT demagnetisation, saturation curve, and knee point
- CT ratio and phase errors across multiple burdens and currents
- CT composite error, FS (Instrument Security Factor), and ALF (Accuracy Limit Factor)
- Secondary terminal voltage (Vb)
- Turns ratio, polarity, and phase angle for VTs, and CVTs
- Winding resistance and insulation resistance for CTs, VTs, and CVTs
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Turns Ratio and Winding Resistance Analyser | TWR-250B

Turns Ratio and Winding Resistance Analyser - Overview

This analyser is battery-operated and is designed for measuring transformer winding resistance and turns ratio. It is capable of testing six transformer windings with a single cable connection, as well as three-phase automatic transformer demagnetisation. It has the option of automated test mode, where the instrument operates the tap changer without operator input (minimising the risk of human error) and records winding resistance and turns ratio results based on pre-selected criteria. This also measures excitation current and phase shift. This enables detecting transformer core or winding turns failures which cannot be spotted by measuring turns ratio only. It has a built-in true three-phase power source so it can test transformers with special configurations, such as phase-shifting, rectifiers, arc-furnace, traction transformers. The instrument can output test current up to 25 A DC for winding resistance tests and voltage up to 250 V AC for turns ratio tests, but it can also output a very low-test voltage of 1 V AC, which is necessary for turns ratio verification of the majority of current transformers. It has a large 10.1” graphical touch-screen display with test templates and automatic test mode. Users can create test templates, store and load them with just a few clicks.

Turns Ratio and Winding Resistance Analyser - Features
- Winding resistance measurement
- Demagnetisation
- Turns ratio measurement
- Turns ratio deviation calculation
- Excitation current measurement
- Phase angle measurement
- Automatic vector group detection
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Winding Resistance Meters Single Phase with DRM | RMO-TD Series

Winding Resistance Meters Single Phase with DRM - Overview

The RMO-TD series is designed for winding resistance measurement of inductive objects. It is based on the most advanced switch-mode technology available today. It is accurate (0,1% rdg + 0,1% F.S.), and powerful (up to 60 A). It generates a true DC ripple-free current with automatically regulated measurement and discharging circuit. It can perform simple, quick and reliable transformer on-load tap changer condition assessments. This series enables measurements of a winding resistance in every tap position, current ripple values and transition times during the tap changes. Problems with the connection, contacts, and selector/diverter switch operation can be detected with these measurements. It is equipped with thermal and overcurrent protection. It has a high ability to cancel electrostatic and electromagnetic interference that exists in HV electric fields. This is achieved by a proprietary filtration solution applied to both the hardware construction and the application software implementation.

Winding Resistance Meters Single Phase with DRM - Features
- On-load tap changer (OLTC) dynamic resistance measurement DVtest
- Three measurement channels
- One temperature measurement channel
- Tap changer motor current monitoring channel
- Built-in tap changer control unit
- Automatic resistance measurement for the Heat Run test
- Rapid automatic demagnetisation
- Automatic discharge circuit
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Single Phase Winding Resistance Meters | RMO-TW Series

Single Phase Winding Resistance Meters - Overview

This series is ideal for measuring the winding resistance of inductive objects. It is perfect for testing transformer windings (power transformers, distribution, autotransformers) and for on-load tap-changer verification. In addition, it can also perform transformer demagnetisation. The series contains 4 models, with maximal test currents from 10 A (RMO10TW) to 50 A (RMO50TW). They are fitted in a portable and lightweight metal housing. Rack-mount available on request. It generates a true DC ripple-free current with an automatically regulated measurement and discharging circuit. The injection of current and discharge of energy from the test object is automatically regulated. Three independent channels enable the testing of three windings in series. Consequently, this enables measurements of winding resistance in every tap position of an on-load tap changer without discharging between the tests. The software enables control and observation of the test process, as well as saving and analysing the results on a PC. It provides a test report, arranged in Excel spreadsheet, PDF, Word, or ASCII format. Additionally, DV-Win measures and calculates the OLTC transition time, the ripple, and the winding resistance for each tap-changing operation.

Single Phase Winding Resistance Meters - Features
- Test Voltage up to 55 V DC
- Simultaneous Three-Channel Winding Resistance Measurement
- On Load Tap Changer Verification
- Transformer Demagnetisation
- DV-TR Software
- Heat Run Test Application
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Winding Resistance and Turns Ratio Meter | MRC7300A

Winding Resistance & Turns Ratio Meter - Overview

This instrument can precisely and safely determine winding resistances, transformation ratios, and phase angles of distribution transformers up to 100MVA and more. Further, it is possible to automatically move the tap charger of the H.V. winding to the next tap and perform cool-down measurements in temperature rise tests to calculate the resistance in the case of a load disconnection. The Winding Resistance & Turns Ratio Meter MRC7300A can be used by transformer manufacturers, electricity supply companies, and repair companies which carry out on-site measurements under unfavourable conditions. Resistance values ranging from 50 µΩ to 500 µΩ can easily be measured and logged with the internal measuring current of a maximum of 15 A up to a power of Approx. 100 MVA and more. To allow a comparison of the measured values to previous measurements, a conversion of the temperature of the test object is provided to compare measurements of a detached transformer carried out in winter and measurements carried out in other seasons. The measuring range is between 0.9:1 and 2500:1 in the case of the transformation ratio; the resolution of the angle measurement is 0.1 degrees. The logging of all measured values is performed by a separate printer, computer, or via the internal memory. The magnetic loading of the transformer is performed quickly to a relatively high rating voltage (50V). The unloading of the core is very safe, as the energy is dissipated in the MRC7300A by a ballast resistor and varistors except for a negligible rest.

Winding Resistance and Turns Ratio Meter- Features
- Automatic measurement without any manual interaction
- Resistance measurement with high accuracy and up to 15 A current
- Ratio measurement including phase angle and magnetizing current
- Dual measuring method for faster measurements
- Automatic vector group detection
- Tap changer control measures all transformers tap automatically
- Heat-up measurement including an algorithm for resistance at t=0
- Temperature measurement and compensation to 20 °C for Cu or AI
- USB port to get full external control over the instrument
- Thermo printer
Datasheet

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