TWR-H - DV Power Handheld Turns Ratio & Winding Resistance Tester

The Handheld TWR-H device is DV Power single-phase instrument designed for measuring transformer winding resistance and turns ratio.

The instrument has two output DC sources for measuring transformer winding resistance. The first DC source can output up to 2 A DC and is used for injecting current into the transformer’s high-voltage winding. The second DC source can output up to 10 A DC and is used for testing the transformer’s low-voltage winding. This is especially useful when measuring the winding resistance of distribution transformers. These transformers have a large turns ratio and therefore a big difference between resistances of high voltage and low voltage windings. Upon the winding resistance test, it is also possible to demagnetize the transformer core. The demagnetization process is completely automatic and safe.

Together with the turns ratio, the instrument 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. The instrument can output test voltage up to 40 V AC for this test, 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.

The list of instrument applications includes:

• Winding resistance measurement of distribution and instrument transformers, motors, and generators
• Turns ratio measurement of distribution transformers
• Turns ratio verification of instrument transformers
• Turns ratio deviation calculation
• Excitation current measurement of distribution and instrument transformers
• Phase angle measurement of distribution and instrument transformers
• Polarity check of instrument transformers
• Demagnetization of distribution and instrument transformers, motors, and generators

TWR-H is powered by an internal Li-Ion battery. Up to 100 tests can be performed with a fully charged battery.

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