MIDDLE EAST TECHNICAL UNIVERSITY

EE 362 EXPERIMENT #1

MMF WAVEFORMS PRODUCED BY POLYPHASE WINDINGS

LABORATORY REPORT

Date of the Experiment Performed: 28.03.2012 Thursday Afternoon Date of Submission: 04.03.2012 Group Members: Tayfun Şentürk - 1675263

Kaan Tosun - 1674662

Ahmet Öner - 1674993

Ufuk Tamer – 1674597

Can Tunca – 1741644

RESULTS

1.

i.)Theoretical MMF Waveform When 2A DC is supplied to 1 Phase of

the Stator Winding

ii.) Theoretical MMF Waveform When 2A DC is supplied to all 3 Parallel Connected Phases of the Stator Winding

A1 A2 A3 A4 –C1 –C2 –C3 –C4 B1 B2 B3 B4 –A5 –A6 –A7 –A8 C5 C6 C7 C8 –B5 –B6 –B7 –B8

A15 A16 –C13 –C14 –C15 –C16 B13 B14 B15 B16 –A1 –A2 –A3 –A4 C1 C2 C3 C4 –B1 –B2 –B3 –B4 A5 A6

A1 A2 A3 A4 –C1 –C2 –C3 –C4 B1 B2 B3 B4 –A5 –A6 –A7 –A8 C5 C6 C7 C8 –B5 –B6 –B7 –B8

A15 A16 –C13 –C14 –C15 –C16 B13 B14 B15 B16 –A1 –A2 –A3 –A4 C1 C2 C3 C4 –B1 –B2 –B3 –B4 A5 A6

iii.) Theoretical MMF Waveform When 2A DC is supplied to all 3 Series

Connected Phases of the Stator Winding

2.

A1 A2 A3 A4 –C1 –C2 –C3 –C4 B1 B2 B3 B4 –A5 –A6 –A7 –A8 C5 C6 C7 C8 –B5 –B6 –B7 –B8

A15 A16 –C13 –C14 –C15 –C16 B13 B14 B15 B16 –A1 –A2 –A3 –A4 C1 C2 C3 C4 –B1 –B2 –B3 –B4 A5 A6

3.

CONCLUSION:

1. The 3 phase winding on the rotor is excited by balanced 3 phase AC at 50 Hz.

Synchronous speed:

a) Rotor speed in the opposite direction to rotor’s mmf

Frequency of search coil:

( )

b) Rotor speed= in the same direction as rotor’s mmf

Frequency of search coil=

( )

2. The 3 phase winding on the stator is excited by balanced 3 phase AC at 50 Hz.

Synchronous speed:

a) Rotor speed in the opposite direction to rotor’s mmf

Frequency of search coil:

( )

b) Rotor speed= in the same direction as rotor’s mmf

Frequency of search coil=

( )

3. When we excite the windings with AC, the resulting MMF waveform is either a

pulsating standing wave (when the only one wave is excited) or rotating MMF wave

(when all phases are excited by balanced 3 phase AC). Therefore, we observe a sine

wave instead of stepped waveform on the oscilloscope.

4. If the speed of rotor is changed, the frequency changes. The peak to peak value of

the induced voltage depends on the peak to peak value of the excitation current.

Therefore, the setup in the procedure 7 can be used for this purpose.

5. As can be seen from the experimental data, the peak value of the induced voltage

depends on the rotor position. Therefore, we can change the rotor position to adjust

the peak value of the induced voltage.

PROCEDURE:

QUESTION 2

QUESTION 3

QUESTION 6