prosedur percobaan motor sinkronsinkron generator sinkron.docx

7/21/2019 Prosedur Percobaan Motor SinkronSinkron Generator Sinkron.docx

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EM 4: SYNCHRONOUS GENERATOR

Task: to measure some of the characteristics for a three phase synchronous

generator

Theory: The characteristics here measured are the no load characteristics, the short

circuit characteristics and the load characteristics

Circuit diagram:

Equipment:

M = Electric torque meter MV 100

G = Synchronous machine MV 122

TG = Tachometer generator MV153

Rmy = Shunt rheostat TS 500/440


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U = Voltmeter 300 V TI 105

Im = Ammeter 1.6A TI 101

IA = Ammeter 6A TI 102

S = Switch TO 3

RB = Load resistor TB 40

F = Power pack TF 123A

For later use

XL = Load inductor TB 41

XC = Load capacitor TB 42

1. Connecting up and start

1.1 Connect the torque meter as motor and the synchronous machine as generator in

accordance with the circuit diagram

1.2 Make a note of the ratings of the synchronous machine shown on the rating plate on

the rear of the machine. These ratings must not be exceeded at any time during the

laboratory exercises

1.3 The supervisor should now check the connections

1.4 Turn on the fixed DC voltage switch

Adjust the shunt rheostat of the torque meter so as to obtain max excitation current.

The switch S must be off

1.5 Set the variable DC voltage control on the power pack to zero and turn on the

variable DC voltage switch. Then slowly turn up the variable DC voltage to 230V and

continuously check the rotor current on the ammeter of the torque meter. The motor

should rotate in the direction of the arrow

1.6 Adjust the torque meter to bring the speed to exactly 1500 rpm. This speed must be

kept constant throughout the exercise


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IA

U

= -90o

= +90o

= 0o

2. Measurement of no load characteristic

i.e. the induced no load voltage as function of the exciting

current

2.1 The switch S must be off. Vary the excitation current Im in

steps of 0.2A from zero to maximum (see ratings). For

every step make a note of Imand the induced voltage read

on the voltmeter U

Check the speed!

3. Measurement of short circuit characteristic

i.e. the armature current as function of the excitation current when the stator is short

circuited

3.1 Adjust the shunt rheostat Rmyof the synchronous machine

to bring the excitation current to zero. Short circuit all three

phases on the S on the side on which the load resistor is

connected

3.2 Turn on switch S. Vary the armature current in steps of 0.5A from zero to maximum

(see ratings) with the shunt rheostat Rmyand for each step make a note of IAand Im

Check the speed!

3.3 Adjust the shunt rheostat of the synchronous machine to bring the exciting current to

zero. Turn off switch S and remove the short circuit

4. Measurement of load characteristic

i.e. the generator voltage as function of the armature current

4.1 Adjust the shunt rheostat Rmy of the synchronous machine

to bring the voltage (U) to 220V. Make a note of setting of

the generator exciting current Im. This value of Im, like the

speed, must be keptconstantthroughout the experiment and

should therefore be checked from time to time

4.2 Turn on switch S and with the load resistor RBvary the armature current in steps of

E

Im

IA

Im


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0.5A up to maximum (see ratings)

For each step make a note of current IA and voltage U

Check the speed excitation current and speed!

4.3 Turn off switch S and replace the load resistor by the delta connected load inductor

4.4 Turn on switch S and with the load inductor vary armature current in steps up to

maximum (see Ratings). For each step make a note of current IA and voltage U


4.5 Turn off switch S and replace the load inductor by the star connected load capacitor

4.6 Turn on switch S and with the load capacitor vary armature current in steps up to

maximum (see Ratings). For each step make a note of current IA and voltage U.terminate the measurement when the voltage has risen to 300V.


Tasks

a. Draw graphs of the no load characteristic and short circuit characteristic in the same

diagram and with common Imaxis

b. Draw graphs of the three load characteristics in the same diagram and with common

IAaxis

c. Read the no load characteristic the excitation current Imo corresponding to the read

voltage

d. Read the short circuit characteristic the short circuit current Iko obtained at the

excitation current Imo

e. Calculate the synchronous reactance of the generator per phase as :

f. calculate the short circuit ratio of the generator

, where In= rated current of

the generator.


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g. Draw three vector diagrams to scale with E = 127V, IA = 2A and = 0o, +90

o, -90

o

respectively. The numerical values of Xswill be obtained from task e

Read U in the vector diagrams and compare with the corresponding values on the

load characteristic

No load Short circuit Load characteristic

characteristic characteristic

Im= const =

= 0o = +90o = -90

o

Im

(A)

E

(V)

Im

(A)

IA

(A)

IA

(A)

U

(V)

IA

(A)

U

(V)

IA

(A)

U

(V)

0 220 0 220 0 220


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EM 5: SYNCHRONOUS MOTOR

Task: To synchronous a synchronous machine to a three phase mains and to study

its properties when connected to a power bus

Theory: The synchronous machine is started with the torque meter and the

synchronization is done by means of sequential lighting of the synchronous

lamp. The machine is then drive as synchronous capacitor and as motor

Circuit Diagram:

A

rpm

TG M

A Im

RB

S

F1

F2

Rmy

F1

F2 A2

A1 U1 V1 W1

U2 W2V2

F

- +

220 V

220 V

IA

P

3x220 V

G

F0 R S T

Cos meter


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Equipment :

G : Electric torque meter MV 100

M : Synchronous machine MV122

TG : Tachometer generator MV153

Rmy : Shunt rheostat TS 500/440

UG, UN : Voltmeter 240V TI 105

IA : Ammeter 6A TI 102

Im : Ammeter 1.6A TI 101

S : Switch T0 30

K : Terminal board with short circuit button TM 125

Z : Synchronizing device TI 21

E : Power factor meter 5A (Cap. 0.5-1-0.5 Ind)

P1 : Wattmeter, single phase, 240V 5A

RB : Load resistor TB 40

F : Power pack TF 123A

1. Connecting up and start

1.1 Connect the torque meter as motor and the synchronous machine for

synchronization in accordance with the circuit diagram. The load switch S and the

switch on the synchronizing device must be off

1.2 Make a note of the ratings of the synchronous machine marked on the rating plate.

These ratings must not be exceeded at any time during the laboratory exercise

1.3 The teacher check the connections

1.4 Turn on the fixed DC voltage switch. Adjust the shunt rheostat of the torque meter so

as to obtain max excitation current

1.5 Set the variable DC voltage control on the power pack to zero and turn on thevariable DC voltage switch. Then slowly turn up the DC voltage to 22V and

continuously check that the current is not too great for ammeter of the torque meter.

The motor then starts and comes up about 1450 rpm

1.6 Adjust the torque meter to bring the speed to exactly 1500 rpm


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3. The synchronous motor as phase compensator

Measurement of V characteristics , i.e. the rotor current as function of the

exciting current of the synchronous motor

3.1 With the shunt the rheostat Rmyvary the excitation current of

the synchronous motor in steps of 0.2A from maximum to

minimum as determined by the current ratings of the

synchronous motor (see ratings). For each step make a note

of Im, IA, UN, P1 and cos. If in any measurement the power

factor deflection goes outside the scale, note ind and cap. Observe that with

overexcited synchronous motor the power factor must be capacitive

3.2 Adjust the shunt rheostat Rmyof the synchronous motor to bring the rotor current to

minimum. Adjust the shunt rheostat of the torque meter to bring the excitation current

to zero, set the load resistor RBto minimum load current and turn on switch S

3.3 Turn up the shunt rheostat and load resistor of the torque meter to bring the torque to

3.0 Nm

3.4 With the shunt rheostat Rmyvary the excitation current of the synchronous motor in

steps from maximum to 0.4A in steps of 0.1A. For each step make a note of I m, IA,

UN, P1 and cos. Check that the torque is 3.0 Nm throughout.

4. The synchronous machine as driving motor

Measurement of power characteristics and , i.e. the

armature current and reactive power, respectively, as function of the power output

Pout

IA

Pout

Q

4.1 Adjust the shunt rheostat of the torque meter to bring the torque to minimum. Adjust

the shunt rheostat of the synchronous machine to bring the rotor current to minimum.

Make a note of the excitation current of the synchronous machine. The excitation

current must be kept constant throughout the experiment

Im

IA


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4.2 Load the synchronous machine by varying the shunt rheostat of the torque meter

and the load resistor RB in steps of 0.5A up to the rated current of the synchronous

motor. For each step make a note of M, Im, IA, UN, P1 and cos.

4.3 With the shunt rheostat of the torque meter adjust the torque to minimum. Change

the excitation current of the synchronous machine to 1.0A and maintain this value

constant throughout the experiment

4.4 Load the synchronous machine by varying the shunt rheostat of the torque meter

and the load resistor RB in steps of 0.5A up to the rated current of the synchronous

motor. For each step make a note of M, Im, IA, UN, P1 and cos.

Problem and Tasks

a. Calculate for all measurements:

The total input power Pin = 3 . P1

The apparent power S = 3 . Un . Ia

The reactive power

The power output

Observe the sign of Q which is obtained from cos .

b. Draw graphs of the V-charateristics Ia = f ( Im ) for measurement 3 with common Im

axis.

c. Draw graphs of the power characteristics Ia = f (Pout ) and Q = f(Pout) for

measurement 4.

d. Calculate what percentage of the rated power of the synchronous machine can be

used when operating as overexcited phase compensator.

e. What is it that limits the available power under d?

f. How could the available power be increased when operating as under excited phase

compensator?g. Why is there little change in the active power during measurement 3?


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MEASURED VALUES CALCULED VALUES

Meas.no

M(Nm)

Im(A)

IA(A)

UN(V)

P1(Watt)

cos

S(VA)

Pin(Watt)

Q(VAR) (Watt)

3.1

3.2

3.0

3.0

3.03.0

3.0

3.0

3.0

3.0

3.0

3.0

4.2

4.4

0.8

0.8

0.8

0.8

0.8

0.8

prosedur percobaan motor sinkronsinkron generator sinkron.docx

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