Winding Resistance
The DC resistance of transformer windings, measured for loss calculation and connection quality verification.
Winding resistance is the DC resistance of winding conductors. Serves multiple purposes: calculating I2R losses (load loss component), determining average temperature during heat run (+0.393%/deg C for copper), verifying connection quality (tap changer contacts, brazed joints).
Measured with micro-ohm meters. Corrected to reference temperature (75C per IEC): R2 = R1 x (235+T2)/(235+T1) for copper.
Changes >1-2% from baseline indicate: loose connections, contact degradation, strand breaks, shorted turns.
QDTB measures and documents for every transformer at factory, establishing baselines for maintenance.
Related Products
Related Terms
Copper Loss
Power lost as heat in transformer windings due to electrical resistance, proportional to the square of load current.
Winding
Coils of insulated conductors in a transformer carrying current and linking magnetic flux for energy transfer.
Temperature Rise
The temperature increase of transformer components above ambient at rated load, a key design parameter.
Load Tap Changer (LTC)
A mechanism allowing transformer tap ratio changes while energized and under load for real-time voltage regulation.
More Terms Starting with “W”
Winding
Coils of insulated conductors in a transformer carrying current and linking magnetic flux for energy transfer.
Watt Loss
The total real power loss in a transformer in watts, comprising no-load and load loss components.
Wye-Delta Connection
A three-phase connection with one star and one delta winding providing phase shift and harmonic isolation.
Wind Power Transformer
A transformer for wind energy applications including collector system and GSU transformers.
More in “Diagnostics & Maintenance”
Dissolved Gas Analysis (DGA)
A diagnostic technique analyzing gases dissolved in transformer oil to detect internal faults before they become critical.
Furan Analysis
A diagnostic measuring furan compounds in transformer oil to assess cellulose insulation degradation.
Moisture Content
The amount of water in transformer oil and solid insulation, critical for dielectric strength and insulation life.
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