n-channel JFET and p-channel JFET
Residual Current Circuit Breaker
Wien Bridge Oscillator
Transformer Testing | Type Test and Routine Test of Transformer
Transformer Winding Resistance Measurement
Voltage and Turn Ratio Test of Transformer
Vector Group Test of Power Transformer
Open and Short Circuit Test on Transformer
Insulation Dielectric Test of Transformer
Transformer Oil and Winding Temperature Rise Test
Impulse Test of Transformer
Maintenance of Transformer
Sweep Frequency Response Analysis Test | SFRA Test
Installation of Power Transformer
Commissioning of Power Transformer
What is transformer? Definition and Working Principle of Transformer
EMF Equation of Transformer | Turns Voltage Transformation Ratio of Transformer
Theory of Transformer on Load and No Load Operation
Resistance and Leakage Reactance or Impedance of Transformer
Equivalent Circuit of Transformer referred to Primary and Secondary
Hysteresis Eddy Current Iron or Core Losses and Copper Loss in Transformer
Voltage Regulation of Transformer
Single Three Phase Transformer vs bank of three Single Phase Transformers
Parallel operation of Transformers
Magnetizing Inrush Current in Power Transformer
Current Transformer CT class Ratio Error Phase Angle Error in Current Transformer
Voltage Transformer or Potential Transformer Theory
Knee Point Voltage of Current Transformer PS Class
Accuracy Limit Factor and Instrument Security Factor of Current Transformer
Transformer Insulating Oil and Types of Transformer Oil
DGA or Dissolved Gas Analysis of Transformer Oil | Furfural or Furfuraldehyde Analysis
Transformer Accessories | Breather and Conservator Tank | Radiator
Silica Gel Breather of Transformer
Conservator Tank of Transformer
Radiator of Transformer | Function of Radiator
Magnetic Oil Gauge or MOG | Magnetic Oil Level Indicator of Transformer
Oil Winding and Remote Temperature Indicator of Transformer
Transformer Cooling System and Methods
On Load and No Load Tap Changer of Transformer | OLTC and NLTC
Tertiary Winding of Transformer | Three Winding Transformer
Core of Transformer and Design of Transformer Core
Restricted Earth Fault Protection of Transformer | REF Protection
Buchholz Relay in transformer | Buchholz Relay operation and principle
What is Earthing Transformer or Grounding Transformer
Differential Protection of Transformer | Differential Relays
Over Fluxing in Transformer
Electrical Power Transformer | Definition and Types of Transformer
What is Auto Transformer ?
High Voltage Transformer
Distribution Transformer | All Day Efficiency of Distribution Transformer
Dry Type Transformer
Air Core Transformer
Design of Inductor in Switched Mode Power Supply Systems
Design of High Frequency Pulse Transformer
Voltage and Turn Ratio Test of Transformer
Transformer Ratio TestThe performance of a transformer largely depends upon perfection of specific turns or voltage ratio of transformer. So transformer ration test is an essential type test of transformer. The voltage should be applied only in the high voltage winding in order to avoid unsafe voltage.
Ratio Test of Transformer and Check of Phase DisplacementActually the no load voltage ratio of transformer is equal to the turn ratio. So ratio test of transformer.
Procedure of Transformer Ratio Test
- First, the tap changer of transformer is kept in the lowest position and LV terminals are kept open.
- Then apply 3-phase 415 V supply on HV terminals. Measure the voltages applied on each phase (Phase-phase) on HV and induced voltages at LV terminals simultaneously.
- After measuring the voltages at HV and LV terminals, the tap changer of transformer should be raised by one position and repeat test.
- Repeat the same for each of the tap position separately.
Let's have a discussion on transformer turns ratio (TTR) meter method of turn ratio test of transformer. A phase voltage is applied to the one of the windings by means of a bridge circuit and the ratio of induced voltage is measured at the bridge. The accuracy of the measuring instrument is < 0.1 %.
This theoretical turn ratio is adjusted on the transformer turn ratio tested or TTR by the adjustable transformer as shown in the figure above and it should be changed until a balance occurs in the percentage error indicator. The reading on this indicator implies the deviaton of measured turn ratio from expected turn ratio in percentage.