The voltage induced in secondary winding of transformer either in phase arrangement or a position comparison with primary voltages how the output terminal are consider when the terminal have been (DO).For high voltages and (c,d,a) for low voltage when the voltage induced between d and q in phase with voltage induced between d and q in phase with voltage induced the polarity is said to be subtractive otherwise polarity is addition.
When two corresponding terminals (Dand q) have been interconnected a suitable voltage is connected to one of the winding DO and the voltage assured between other two terminal.Q and q if the voltage connected between the terminals DO. The polarity is subtractive otherwise it is additive.
The short circuit test consists in measuring the input characteristics (quantities) of the transformer when the secondary side is shorted and the primary side is supplied with a suitable decreased voltage so that the current in the winding are equal to related current.The purpose of the test is to determined:
(1)The value of copper loss in the winding
(2)The value of short circuit voltage (Vsc) ,resistance (Ro1) and reactance (Xo1).
The instruments are arranged as for the circuit diagram and small voltage about 10% of the rotted value is supplied to primary side keeping the secondary side short circuited.Voltage is gradually increased till rotted current flow in winding which is recorded by ammeter.This value of voltage whose cause to flow rotted current in short circuited condition is called short circuited voltage (Vsc).
Watt meter reading gives the value of 'Cu' loss.Iron in this case is very much negligible (But value is same as in no-load) then Cu loss.Copper loss depend on current similarly iron loss depend on voltage therefore copper loss is negligible in no-load and iron loss is neglible in short circuit condition.
(1)The value of copper loss in the winding
(2)The value of short circuit voltage (Vsc) ,resistance (Ro1) and reactance (Xo1).
The instruments are arranged as for the circuit diagram and small voltage about 10% of the rotted value is supplied to primary side keeping the secondary side short circuited.Voltage is gradually increased till rotted current flow in winding which is recorded by ammeter.This value of voltage whose cause to flow rotted current in short circuited condition is called short circuited voltage (Vsc).
Watt meter reading gives the value of 'Cu' loss.Iron in this case is very much negligible (But value is same as in no-load) then Cu loss.Copper loss depend on current similarly iron loss depend on voltage therefore copper loss is negligible in no-load and iron loss is neglible in short circuit condition.
When a test is performed by leaving one winding open and giving supply to the another side,the test on the transformer is performed to ensure the working condition to the transformer.The main of the open circuit test are as follows:
(a)To find no-load current (Io)
(b)To obtain no-load parameters i.e,IuIwRo1Xo
(c)To find core loss (V1Iocos)
Supply is given to low voltage side of the transformer because it is either to use lower rating equipment for the measurement.Supply is given through auto transformer to get variable voltage and also for matching winding voltage capacity.Supply voltage V1 is indicated by voltmeter,no load current.Io is measured by ammeter and core loss is given by watt meter.Secondary side was no current hence there is no copper (Cu) loss and primary side has small amount of no load current hence small copper loss is there which can be ignored.In this way,open circuit test is carried out in the transformer.
(a)To find no-load current (Io)
(b)To obtain no-load parameters i.e,IuIwRo1Xo
(c)To find core loss (V1Iocos)
Supply is given to low voltage side of the transformer because it is either to use lower rating equipment for the measurement.Supply is given through auto transformer to get variable voltage and also for matching winding voltage capacity.Supply voltage V1 is indicated by voltmeter,no load current.Io is measured by ammeter and core loss is given by watt meter.Secondary side was no current hence there is no copper (Cu) loss and primary side has small amount of no load current hence small copper loss is there which can be ignored.In this way,open circuit test is carried out in the transformer.
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