The handheld winding ohmmeter RMO-TH device is DV Power single-phase instrument specially designed for measuring transformer winding resistance and performing transformer demagnetization. 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.
After the winding resistance test, RMO-TH can demagnetize the transformer core. The demagnetization process is completely automatic and safe.
The list of instrument applications includes:
- Winding resistance measurement of distribution and instrument transformers, motors, and generators
- Demagnetization of distribution and instrument transformers, motors, and generators
RMO-TH is powered by an internal Li-Ion battery. Up to 100 tests can be performed with a fully charged battery. The battery charging time is 2.5 hours.
Up to 10 A DC for LV side