mesin sinkron [autosaved]
TRANSCRIPT
MESIN ELEKTRIK I
Oleh : Ir. Hery Purnomo, MT
Mesin sinkron
APLIKASI
MESIN SINKRON (Mesin Serempak)
1.Generator Sinkron a). Generator sinkron 3 fasa
b). Generator sinkron 1 fasa
PLTA, PLTD,PLTU, PLTG, PLTGU, PLTN, ………..dsb.(Pembangkit tenaga listrik arus bolak-balik)
2.Motor sinkrona). Motor sinkron 3 fasa motor penggerak beban mekanik kapasitas besar
P>200 HP, tegangan menengah (4000 – 6000V)b). Motor sinkron 1 fasa motor penggerak mekanik ukuran kecil, yang digunakan
pada peralatan kontrol (motor servo, motor sinkro)
Konstruksi Mesin Sinkron
1.Mesin sinkron Kutub dalam (kutub maknit berputar, dirotor)
2.Mesin sinkron Kutub luar (kutub maknit diam, distator)
Kutub luar
Belitan medan Belitan jangkar / Bel. tenaga
Kutub dalam
Belitan jangkar / Bel. tenaga Belitan medan
Magnet permanen
1). Kutub silindris (non salient pole) 2). kutub tonjol (salient pole)
Mesin sinkron kutub dalam
Kutub tonjol
• Kutub banyak• Putaran rendah (n < 1000 rpm)• Aplikasi : PLTA
8
PLTA
Stator under construction
• Kutub sedikit• Putaran tinggi (n > 1000 rpm)• Aplikasi : PLTU, PLTD, PLTN, …..
Kutub silindris
Steam Turbine(PLTU)
Power Station(PLTN)
Macam belitan Mesin sinkron :1). Belitan Jangkar (belitan stator)2). Belitan medan
Belitan jangkar
Belitan medan
Konsep dasar generator sinkron (kutub luar)
Magnet tetap
Generator sinkron kutub dalam
(Belitan medan)
(Belitan jangkar)
Konsep dasar generator sinkron 3 fasa.
Mesin sinkron 3 fasa, kutub dalam
N
S
a
c b
a'
c'b'
ia
ib
ic
Statorwindings
a'
b'
c'
BSV f
a
b
c
+
–
n
Important Characteristics of Alternators
• The output frequency of an alternator can be varied only
by changing the rotor speed.
• The output voltage of an alternator can be varied by
changing either the field current or the rotor speed.
Important Characteristics of Alternators
• Power losses in the brushes and slip rings is relatively small.– Brushed and slip rings are in the field circuit.– Field current is low.
• The output current capacity of the alternator can be increased simply by increasing the size of the stator wire.– Higher output current will cause a proportional increase in the
input shaft torque.– This will increase in the mechanical stress on the field windings.
• The rotating field causes an alternating field in the stator core.– The core will suffer hysteresis and eddy current losses.– The stator core must be laminated to minimize eddy currents.– The magnetic field in the rotor core is constant, so the rotor core
does not need to be laminated.
Two-pole three-phase alternator armature.
A 12-V dc automotive alternator system.
Output Frequency
• f = (P nr) / 120– f = the frequency in Hertz (Hz)– P = the number of poles per output phase
(dimensionless)
– nr = the rotor speed in revolutions per minute (rpm)
Mesin sinkron 4 kutub
1) Gambarkan bentangan/skema belitan medan2) Gambarkan bentangan belitan jangkar mesin sinkron 1 fasa3) Gambarkan bentangan belitan jangkar mesin sinkron 3 fasa
Rangkaian ekuivalen mesin sinkron
Generator (Appx.)Motor(Appx.)
Generator (Exact)Motor(Exact)
•Only difference is in current direction; in a generator it flowsout of it, in case of a motor it flows into it.
Machine
Machine
Machine
Machine
Rangkaian ekuivalen mesin sinkron
Machine Machine
Xs=Xar+Xal (Synchronous reactance)Zs= Ra+jXs (Synchronous impedance)Xal is leakage ReactanceRa is armature resistance
Generator (Exact)Motor(Exact)
Phasor diagram mesin sinkron
Note: is +ve for (a) generator and –ve for (b) motor
Terima Kasih