Category: Winding Resistance Testers

Home -> Category: Winding Resistance Testers

Winding Resistance Testers

Winding Resistance Testers measure highly inductive windings of the transformer, motors, and reactors to analyse the performance of the measured UUT.

Winding Single Phase Resistance Meters | RMO-TT
Call for price
Winding Single Phase Resistance Meters - Overview

The RMO-TT series is designed for winding resistance measurement of inductive objects. It uses advanced switch-mode technology. It is an accurate (0,1% rdg + 0,1% F.S.), and powerful portable instrument (up to 100 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 the 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. Applications include: winding resistance measurement of inductive test objects; dynamic resistance measurement (DVtest) of on-load tap changers; measurement of on-load tap changer motor current by using a dedicated channel; heat run test, which enables obtaining the Hot Spot temperature along with resistance graph during the cooling process 1; and single-phase automatic transformer demagnetisation.

Winding Single Phase Resistance Meters - Features
- On-load tap changer dynamic resistance measurement
- Three resistance measurement channels
- Four temperature measurement channels
- Vibration measurement channel
- Tap changer motor current monitoring channel
- Automatic measurement for the Heat Run test
- Rapid automatic demagnetisation
- Automatic discharge circuit
Read more
Winding Resistance Meters Single Phase with DRM | RMO-TD Series
Call for price
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
Read more
Handheld Winding Ohm Meter | RMO-TH Series
Call for price
Handheld Winding Ohm Meter - Overview

The handheld winding ohm meter device is a DV Power single-phase instrument specially designed for measuring transformer winding resistance and performing transformer demagnetisation. Winding resistance is determined by injecting DC current through a winding, accurately measuring DC voltage across the winding, and then calculating resistance as the ratio of voltage and current. The device generates true DC ripple-free currents. Both the injection of the current and the discharge of energy from the transformer magnetic circuit are automatically regulated. The instrument has two output DC sources for measuring transformer winding resistance. The first DC source can output a maximum of 2 A DC and is designed for injecting current into the transformer’s high-voltage winding. The second DC source can output a maximum of 10 A DC and is designed for testing the transformer’s low-voltage winding. Having two separate DC sources is especially useful when measuring the winding resistance of distribution transformers. These transformers have a large turns ratio. Because of that, the difference between resistances of high voltage and low voltage windings is very big. This requires different levels of test currents for high-voltage and low-voltage windings. Applications include: winding resistance measurement of distribution and instrument transformers, motors, and generators, and demagnetisation of distribution and instrument transformers, motors, and generators.

Handheld Winding Ohm Meter - Features
- Two Output DC Sources
- Memory
- DV-TR Software
- Internal Li-Ion battery
Read more
4
Winding Resistance and Turns Ratio Meter | MRC7300A
Call for price
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

Read more
Winding Resistance Transformer and Motor Meter | MR 8050
Call for price
Winding Resistance Transformer and Motor Meter - Overview

The MR8050 can measure highly inductive windings of transformers, motors, and reactors with a range of 100µΩ with 0.01µΩ resolution up to 6kΩ. The performance of the measured objects can be up to 800MVA or even more. The magnetic loading of a transformer is performed quickly using a high loading voltage (60V), this is important for time-critical measurements (cooling curves). The unloading of the transformer's core is fast and safe, as the energy is dissipated in the MR8050. The temperature of the measured objects can be pre-set or measured using a PT100 temperature sensor and the resistance is calculated for 20°C using the temperature coefficient for copper or aluminum heat-loss measurements. The resistance at t=0 (disconnection of load) is shown as a result of the internal regression algorithm. Two windings (mostly HV and LV) can be measured simultaneously in the DUAL measuring method. The MR 8050 also features automatic tap-changer control for measuring different taps without interrupting the measuring current.

Winding Resistance Transformer and Motor Meter - Features
- 2 channels for DUAL measurements
- Measuring time short due to very fast uploading
- Discharge time 1/10 of uploading time
- Heat - loss measurements with regression algorithm
- LCD-Display with 240 x 128 pixels with backlight
- USB standard and RS232C 9600 baud
- PT100 connector for PT100 temperature probe
- Tap changer connector for automatic tap control
- Warning system connector for a separate warning light
- Internal test storage for up to 1000 measurements
- Inputs full protected against static and transient voltages
- Wide current ranges from 50mA to 60A
Datasheet

Read more
Advanced Three-Phase Winding Resistance Meters | TWA Std Series
Call for price
Advanced Three-Phase Winding Resistance Meters - Overview

The TWA Standard series has LCD displays. Both models are capable of testing six transformer windings with a one-time cable connection, as well as three-phase automatic transformer demagnetisation. The stored magnetic energy is safely and automatically discharged at the end of the test. The built-in tap changer control unit enables automated test mode, where the instrument operates the tap changer without operator input and records winding resistance results based on pre-selected stabilisation criteria. Both models can output test currents from 5 mA to 30 A DC for the purpose of winding resistance measurement. TWA40D has a special test mode for checking the synchronisation of on-load tap changers with three phases simultaneously tested in parallel, in which the total test current can rise to up to 40 A DC. The unique DVtest method enables checking the moving contacts of on-load tap changers during the transition, measuring the transition time, detecting open circuits, and many other types of faults. It is performed with a 0.1 ms sampling rate, simultaneously with the measurement of the tap changer motor current, which helps with the detection of motor and mechanical issues. An algorithm is used for testing tap changers connected through a built-in series (booster) transformer. The DVtest can be performed either on one phase or on three phases simultaneously. It can also be performed as an additional test, simultaneously with the winding resistance test in all tap positions.

Advanced Three-Phase Winding Resistance Meters - Features
- Resistance measurement of all tap positions in all six windings performed in a single test
- True three-phase on-load tap changer (OLTC) DVtest (dynamic resistance measurement)
- Quick measurement, single-step cable setup
- Rapid automatic demagnetisation
- Fully automated test mode
- Built-in tap changer control unit
- Temperature measurement channel
https://www.youtube.com/watch?v=aUJ0BNudhI4

Read more
1
Three Phase Transformer Measuring Bridge | MLS 7100
Call for price
Three-Phase Transformer Measuring Bridge - Overview

The MLS 7100 was particularly designed to simplify the determination of transformer core and copper losses, which is an ideal choice when working on site. The measuring bridge features open-circuit as well as short-circuit measuring. Many transformers can be directly connected to the MLS 7100 without needing further transducers. Core losses are an important transformer quantity in electrical efficiency, operating expenses, and the overall transformer value.

Steel losses are typically determined using open-circuit measurement, as a relatively small magnetising current is flowing. Using this technique, the copper losses are minimized due to the square correlation of power and current. Copper losses are determined using short circuit measurement, as the magnetising modulation of the steel core should be minimized. In addition, the short circuit voltage is determined this way, which is also an important quantity.

Three Phase Transformer Measuring Bridge - Features
- Open circuit measurements
- Short circuit measurements
- Free selectable voltage and current dividers
- 1000 kV with transducer
- 1000 kA with transducer
- 550 V (chained) 6 A directly connectable
- Measures and displays:
  - Voltages
  - Currents
  - Power
  - Short Circuit Values
  - Frequency
- Centronics printer port
- RS232C port for external control
Datasheet

Read more
Handheld Turns Ratio and Winding Resistance Meter | TWR-H Series
Call for price
Handheld Turns Ratio and Winding Resistance Meter - Overview

This handheld, battery-operated, fully automatic test set is designed for turns ratio, phase shift, excitation current of transformers, and winding resistance measurement of transformers and other inductive objects. It can also perform demagnetisation of transformers, motors, and generators. The device generates true DC ripple-free currents. Both the injection of the current and the discharge of energy from transformer magnetic circuit are automatically regulated.

Handheld Turns Ratio and Winding Resistance Meter - Features
- Unique handheld instrument on the market
- Performs 3 different tests: Turns ratio, Winding resistance, Demagnetisation
- Single-phase test voltage up to 40 V AC
- Two DC current sources: Test current up to 2 A DC for transformer HV side, Test current up to 10 A DC for transformer LV side
- Extremely lightweight – only 1.4 kg / 3.1 lbs
- Battery-powered
- Tests single-phase and three-phase transformers
Read more