To determine the direct axis reactance Xd and quadrature axis reactance Xq by conducting a slip test on a salient pole synchronous machine.

Aim

To determine the direct axis reactance Xd and quadrature axis reactance Xq by conducting a slip test on a salient pole synchronous machine.

Apparatus Required:

Name plate details:-

DC Motor(prime mover)

Rated power:5HP

Voltage:220V

Current:19A

Speed(RPM):1500rpm

Excitation:Shunt

Field current:1.2A

3- ɸ Alternator

Power Rating: 3 kVA

Voltage: 415

Current: 3.8

Speed: 1500rpm

Excitation: Shunt

Field current:1.5

3- ɸ Auto transformer details:

Input voltage: ___415_________________(Volt)

Output Voltage : ____(0-470)_______________(Volt)

Current________6________________(Amp.)

Frequency:________50________________(Hz)

Circuit Diagram:

Procedure:

1. Connections are made as per the circuit diagram
2. Initially set field regulator, 3-ɸ variac at minimum position and TPST switc
3. The DC supply to the field is removed and SPST switch is connected across the field by closing the switch open.
4. Close the TPST switch
5. With field winding left open, a positive sequence balanced voltages of reduced Magnitude (around 25% of rated Value) and of rated frequency are impressed across the armature terminals.
6. The prime mover (DC motor) speed is adjusted till ammeter and voltmeters pointers swing slowly between maximum and minimum positions
7. Under this condition , readings of maximum and minimum values of both ammeter and voltmeter are recorded

Calculations:

X _d=-------------------

X _q=-------------------

Note:

1. When performing this test, the slip should be made as small as possible
2. During Slip test, it is observed that swing of the ammeter pointer is very wide, whereas the voltmeter has only small swing.

Tabular column:

Result:Xd and Xq of a salient pole synchronous motor are determined by conducting slip test