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FORMULA
1. Input Power =Wattmeter reading × Multiplication factor in Watts
Where, Multiplication factor =
2. Output power = VSY × ISY × cosf in Watts.
Where VSY - Secondary Voltage in Volts.
ISY- Secondary current in Amps.
3.Percentage of Efficiency = × 100 %
4.Percentage of Regulation = × 100 %
Where, VO - No Load Voltage in Volts
VL - Load Voltage in Volts
IMPORTANT!
No Load Condition should be observed at the time of starting
Meters are checked for proper Type and rating.
PROCEDURE
Connections are given as per the circuit diagram.
The SPST Switch on the Primary side is closed and the DPST Switch on the Secondary side is opened.
The Autotransformer is adjusted to Energize the transformer with rated Primary Voltage
The Volt meters and Ammeters Readings are noted and tabulated at No load condition
The DPST switch on the secondary side is closed.
The transformer is loaded upto 130% of the Rated Load, corresponding Ammeters, Voltmeters and Wattmeters readings are noted and tabulated.
After the observation of all the readings the load is released gradually to its initial position.
The Autotransformer is brought to its initial position
The Supply is switched off.
To find load test on SF transformer you will need:
AMMETER - Range (0-10)A - (0-5) A Type MI
VOLTMETER (0-150)V - (0-300) V Type MI
Wattmeter (300V, 5A) - (150V, 5A) Type UPF
Auto Transformer 1f, (0-260)V
Resistive load 5KW, 230V
Connecting wires 2.5sq.mm Type Copper
Wiki User
∙ 11y ago
Wiki User
∙ 11y agoYou need a three phase load bank. Hook up proper ampere meters to each leg of the Generator in series. Hook up proper wattmeters. Turn on all breakers
Wiki User
∙ 9y agoA load test on a transformer is done to make sure it stays within its designed temperature range while on full load.
Wiki User
∙ 9y agoThere are three phases in transformer. The 3 phases are phasing out, shift across and winding characteristics.
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Load test on single phase transformer?
The dc tests that can be done on a transformer are to measure the resistance of each windings and to measure the insulation resistance between the windings and between each winding and the transformer case.
What is the role of magnetizing current in transformer?
connect 3 - phase supply to transformer primary winding.....keep transformer secondary winding open..... apply 3-phase voltage i.e.400v ac, and measure the amount of current flowing in each phase of the transformer primary winding...this current is the transformer magnetising current..... we can keep multimeters in series with the source....so we can measure directly the current readings.....(keep multimeters in current mode, and generally magnetising current will come in terms of milli amps for 400 v )
How you differentiate between single phase and three phase transformer?
A single-phase transformer works with a single-phase supply, while a 3-phase transformer is used with a 3-phase supply. A single-phase transformer has 2 wires on the primary and secondary (ignoring taps) while a 3-phase tansformer has 3 or 4 wires on the primary and secondary.
Can 3 single phase transformers can replace 1 three phase transformer?
Yes, you can use three single phase transformers on three phase applications and interconnect them to serve as a single transformer or you could use one single phase transformer fed from two of the three lines in a step down application.
Why starting currrent is higher in 3 phase id motor than 3 phase transformer?
CLARIFICATION AND ANSWER: 1. STARTING CURRENT PRODUCED ONLY BY ITS LOAD NOT SOURCE(SAY STEPDOWN TRAFO) 2. IF THE INDUCTION MOTOR IS THE ONLY LOAD OF THE STEP DOWN TRANSFORMER (SOURCE)-THE READING WILL BE AND SHOULD BE THE SAME IN THE SECONDARY SIDE UNLESS YOUR AMMETER IS IN THE PRIMARY SURELY WILL READ LOWER BUT POWER CONSUMPTION REMAINS THE SAME. 3. IT ALSO DEPENDS ON THE RATING OF THE MOTOR LOAD AND THE TYPE OF STARTING METHOD USED THAT YOU CAN MEASURE STARTING CURRENT.
Load test on single phase transformer?
The dc tests that can be done on a transformer are to measure the resistance of each windings and to measure the insulation resistance between the windings and between each winding and the transformer case.
How many 16 Amps per phase welding outlet can you install to a 30 KvA rating transformer?
..the questions does not say wether the 30kVA transformer is 3 phase transformer or single phase transformer..but it is implying that a single phase welding load at 16A per phase is to be connect to it, it is assumed then that the transformer is 3 phase transformer..we assume load is rated 240V.. ..though not much details is given about the transformer voltage specs. but if is rated 3 phase 415/240V, the approx full load current per phase is given by 30KVAx1.3912=41.736A.. ..but if the transformer was rated single phase 240V say, the approx full load current FLC=30000/240V gives 125ampers.. ..if you further devide the FLC by the intended load current.. ..Recommended no of welders per for a 3 phase 415V transformer and assuming single welding sets =41.736/16=2.6..so you can connect max two welding sets to this transformer per phase,..max 6 weld sets can connect at an approx load factor of 76%.. ..for the single phase transformer, FLC/16=125/16, gives 7.8 but is also recommended not to connect more than 6 welding sets to such transformer for the same reasons..
In a 3-phase high voltage star-star connection 140KVA transformer and load phase voltage is 115v and frequency is 400hz what is the total load current?
Maximum load current on a 140KVA, three phase transformer when the output voltage is 115 v phase to phase is: 140kva / sqrt (3) / 115 = 703 Amps. frequency does not matter here.
Load test on 3 phase induction motor?
When you do a load test on a 3-phase induction motor you are checking the power factor, viz slip, and efficiency of the motor. You can test various loads with this test.
How do you get 380 volt from 220 3 phase?
Only with a 3 phase transformer.
What is the difference between isolation transformer and scott-T transformer?
An isolation transformer is used to electrically isolate the load from the power source and is a 1:1 ratio. This is done to prevent a fault on the load from affecting the generator and other loads. A scott-T transformer is used to convert 3 phase AC to 2 phase or vice versa. Applications of this are voltage regulators or cost reduction for short distance 3 phase transmission. Using it for a voltage regulator you could run the 2 phase output through an inductor or capcitor and resistor branch to get a single phase indicative of all three phases of the output of a generator.
What is the role of magnetizing current in transformer?
connect 3 - phase supply to transformer primary winding.....keep transformer secondary winding open..... apply 3-phase voltage i.e.400v ac, and measure the amount of current flowing in each phase of the transformer primary winding...this current is the transformer magnetising current..... we can keep multimeters in series with the source....so we can measure directly the current readings.....(keep multimeters in current mode, and generally magnetising current will come in terms of milli amps for 400 v )
What is the output current of a 480 Volt primary 208 volt secondary - 3 phase transformer?
You need to mention the Load connected to find the current.
How do you convert a 3-phase system to a single phase?
By having a transformer with 3 phase input and single phase out put
How you differentiate between single phase and three phase transformer?
A single-phase transformer works with a single-phase supply, while a 3-phase transformer is used with a 3-phase supply. A single-phase transformer has 2 wires on the primary and secondary (ignoring taps) while a 3-phase tansformer has 3 or 4 wires on the primary and secondary.
What are the advantages of 3-phase transformer over 3 single-phase banks of transformers?
The main advantage is that the 'footprint' of a three-phase transformer is smaller than a transformer bank, and all connections are prewired which makes them easier and quicker to install and replace.
How do you calculate phase voltage of a three phase four wire system?
Phase voltage is determined by the wiring of transformer that serves the building. To test phase voltage use a volt meter and put one probe to ground and the other to each phase and observe the reading, this will give you a phase to ground voltage reading. Next test phase to phase (1 to 2, 1 to 3, and 2 to 3) to see if it's 208, 240, 277, or 480. Only licensed electricians should perform these tests. DAW
