# Electrical Technology Grade 12 NSC November 2025 QP (Eng)

> Grade 12 Electrical Technology question paper from the NSC November Exam 2025 (English), 22 pages. Read online or download the free PDF.

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- Updated: 2026-09-28
- Subject: Electrical Technology
- Grade: Grade 12
- Document type: Question paper
- Year: 2025
- Exam period: NSC November Exam
- Curriculum: CAPS
- Pages: 22

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Electrical Technology · Grade 12 · NSC November Exam · 2025. Question paper, 22 pages. Read online or download the PDF.

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### Page 1

Confidential

                                NATIONAL
                           SENIOR CERTIFICATE

                                   GRADE 12

                ELECTRICAL TECHNOLOGY: POWER SYSTEMS

                                NOVEMBER 2025

MARKS: 200

TIME: 3 hours

        This question paper consists of 20 pages and a 2-page formula sheet.

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Electrical Technology: Power Systems          2                             DBE/November 2025
                                        NSC Confidential

 INSTRUCTIONS AND INFORMATION

 1.        This question paper consists of SEVEN questions.

 2.        Answer ALL the questions.

 3.        Sketches and diagrams must be large, neat and FULLY LABELLED.

 4.        Show ALL calculations and round off answers correctly to TWO decimal places.

 5.        Number the answers correctly according to the numbering system used in this
           question paper.

 6.        You may use a non-programmable calculator.

 7.        Calculations must include:

           7.1        Formulae and manipulations where needed

           7.2        Correct replacement of values

           7.3        Correct answer and relevant units where applicable

 8.        A formula sheet is attached at the end of this question paper.

 9.        Write neatly and legibly.

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Electrical Technology: Power Systems            3                        DBE/November 2025
                                          NSC Confidential

 QUESTION 1: MULTIPLE-CHOICE QUESTIONS                  2025

 Various options are provided as possible answers to the following questions. Choose
 the answer and write only the letter (A–D) next to the question numbers (1.1 to 1.15) in
 the ANSWER BOOK, e.g. 1.16 D.

 1.1       A/An … provides work for another person and remunerates that person.

           A     employee
           B     employer
           C     supervisor
           D     health and safety representative                                               (1)

 1.2       The phase difference between the voltage across the capacitor and the voltage
           across the resistor in an RC series circuit is …

           A     0°
           B     90°
           C     120°
           D     180°                                                                           (1)

 1.3       In an RLC series circuit, the total current lags the supply voltage. This is an
           indication that the frequency is … resonance.

           A     below
           B     equal to
           C     above                                                                          (1)

 1.4       The total impedance in an RLC parallel circuit with a variable frequency supply
           is equal to the … at resonance.

           A     inductive reactance
           B     capacitive reactance
           C     resistance                                                                     (1)

 1.5       The … of the same amount of electrical power is more economical in a
           three-phase system than in a single-phase system.

           A         generation
           B         transmission
           C         distribution
           D         All the above-mentioned                                                    (1)

 1.6       … are used to improve the power factor of induction motors and are mounted
           on the same shaft as the rotor.

           A         Static capacitors
           B         Phase advancers
           C         Inductors
           D         Variable resistors                                                         (1)

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Electrical Technology: Power Systems             4                          DBE/November 2025
                                           NSC Confidential

 1.7       A … is used by electric service providers to measure the electric energy
           delivered to their customers for billing purposes.

           A         wattmeter
           B         kilowatt-hour meter
           C         ammeter
           D         voltmeter                                                                     (1)

 1.8       … configuration is seldom used in three-phase transformers due to the
           presence of harmonics in the secondary windings.

           A         Star-star
           B         Star-delta
           C         Delta-star
           D         Delta-delta                                                                   (1)

 1.9       Eddy currents form part of …

           A         copper losses.
           B         iron losses.
           C         stray losses.
           D         dielectric losses.                                                            (1)

 1.10      The primary function of the stator in a three-phase induction motor is to …

           A         rotate and produce mechanical power.
           B         provide an electrical connection between the rotor and stator.
           C         create a rotating magnetic field when connected to a three-phase supply.
           D         ensure conductivity between the coils and the earth.                          (1)

 1.11      By reversing the connections of any two of the three-phase supply lines in a
           three-phase induction motor, the direction of rotation will change because
           the …

           A         polarity on the contactor coil changed.
           B         phase sequence of the supply voltage to the stator coils changed.
           C         frequency of the power supply is inverted.
           D         motor windings are short-circuited.                                           (1)

 1.12      Once the start button is pressed in a three-phase automatic star-delta motor
           starter, … is/are energised.

           A         only the main contactor
           B         the star and delta contactors
           C         the main contactor and delta contactor
           D         the main contactor and star contactor                                         (1)

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Electrical Technology: Power Systems           5                         DBE/November 2025
                                         NSC Confidential

 1.13      A … is an example of an output device on a PLC.

           A         switch
           B         sensor
           C         relay
           D         strain gauge                                                               (1)

 1.14      A semiconductor device that uses light to transfer an electrical signal between
           circuits or elements of a circuit is called a/an …

           A         diode.
           B         transistor.
           C         opto-coupler.
           D         Zener diode.                                                               (1)

 1.15      The IGBT in a VSD is simulated by using pairs of switches. Which ONE of the
           following simulation statements is CORRECT?

           A         One pair of switches controls the negative output voltage.
           B         One pair of switches controls the positive output voltage.
           C         One switch in a pair controls both the positive and negative output
                     voltage.
           D         None of the above-mentioned                                                (1)
                                                                                                [15]

 QUESTION 2: OCCUPATIONAL HEALTH AND SAFETY

 2.1       Explain machinery with reference to the Occupational Health and Safety Act,
           1993 (Act 85 of 1993).                                                               (2)

 2.2       State TWO precautionary measures to protect yourself when assisting
           someone that has been electrocuted.                                                  (2)

 2.3       Give TWO examples of dangerous practices in the electrical workshop.                 (2)

 2.4       Differentiate between a critical incident and an accident.                           (2)

 2.5       In the electrical workshop, you saw one of your classmates removing a safety
           guard on a machine. According to the Occupational Health and Safety Act,
           1993 (Act 85 of 1993), this is an unsafe act. Motivate why it is an unsafe act.      (2)
                                                                                                [10]

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Electrical Technology: Power Systems           6                          DBE/November 2025
                                         NSC Confidential

 QUESTION 3: RLC CIRCUITS

 3.1       With reference to RLC circuits, state the correct terminology that describes the
           following:

           3.1.1      The frequency at which XL is equal to XC                                   (1)

           3.1.2      The ratio of the energy stored to the energy converted by an inductor
                      or capacitor                                                               (1)

 3.2       FIGURE 3.2 below shows an RLC series circuit connected to an AC supply.
           Answer the questions that follow.

                      VR = 202,16 V           VL = 226,82 V      VC = 140,18 V

                             R                 XL = 62,83 Ω         C = 100 µF

                       IT = 3,61 A

                                                    50 Hz

                                     FIGURE 3.2: RLC SERIES CIRCUIT

           Given:

           IT         = 3,61 A
           XL         = 62,83 Ω
           C          = 100 μF
           VR         = 202,16 V
           VL         = 226,82 V
           VC         = 140,18 V
           f          = 50 Hz

           Calculate the following:

           3.2.1      Supply voltage                                                             (3)

           3.2.2      Impedance                                                                  (3)

           3.2.3      Phase angle                                                                (3)

           3.2.4      Capacitance value that will cause resonance                                (3)

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Electrical Technology: Power Systems          7                         DBE/November 2025
                                        NSC Confidential

 3.3       Redraw and complete the voltage phasor diagram of QUESTION 3.2 in
           FIGURE 3.3 below in the ANSWER BOOK.

                                         IT = 3,61 A

                      FIGURE 3.3: INCOMPLETE VOLTAGE PHASOR DIAGRAM                             (4)

 3.4       FIGURE 3.4 below shows an RLC parallel circuit with its corresponding phasor
           diagram. Answer the questions that follow.

                                                           IC = 0,2 A

                                                                IR = 0,5 A    VT = 50 V
                50 Hz             R       L       C

                                                           IL = 0,9 A

                     FIGURE 3.4: RLC PARALLEL CIRCUIT AND PHASOR DIAGRAM

           Given:

           VT        = 50 V
           IR        = 0,5 A
           IL        = 0,9 A
           IC        = 0,2 A
           f         = 50 Hz

           Calculate the following:

           3.4.1        Total current                                                           (3)

           3.4.2        Capacitive reactance                                                    (3)

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Electrical Technology: Power Systems          8                            DBE/November 2025
                                        NSC Confidential

 3.5       State whether the circuit in FIGURE 3.4 on the previous page is more capacitive
           or more inductive. Give a reason for the answer.                                      (2)

 3.6       Refer to FIGURE 3.4 on the previous page and explain how an increase in the
           supply frequency will cause the circuit to resonate.                                  (3)

 3.7       FIGURE 3.7 below shows the frequency response curve of an RLC circuit, NOT
           to scale. Answer the questions that follow.

                                Zmax

                              70,7%

                                              5,4   7,3    9,2   f (kHz)

                        FIGURE 3.7: Q-FACTOR CHARACTERISTIC CURVE

           3.7.1      State whether FIGURE 3.7 above represents the response curve for
                      a series or parallel RLC circuit and motivate the answer.                  (2)

           3.7.2      Calculate the Q-factor of the circuit.                                     (4)
                                                                                                 [35]

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Electrical Technology: Power Systems            9                            DBE/November 2025
                                          NSC Confidential

 QUESTION 4: THREE-PHASE AC GENERATION
 4.1       State TWO disadvantages of three-phase systems.                                         (2)
 4.2       Describe what is meant by a power factor of less than 1 in a three-phase
           system.                                                                                 (2)
 4.3       Refer to FIGURE 4.3 below which shows the coil configuration of a balanced
           three-phase system connected to a 400 V three-phase supply. Answer the
           questions that follow.

                                                                                   R

                                                                        L1

                      VL
                                R                                                  Y
                     400 V

                                                                L2                L3

                                                                                   B

                           FIGURE 4.3: BALANCED THREE-PHASE LOAD
           4.3.1       Identify the configuration of the coils in FIGURE 4.3 above.                (1)
           4.3.2       Determine the voltage across L2 in FIGURE 4.3 above.                        (1)
           4.3.3       Draw the phasor diagram of the system in FIGURE 4.3 above.                  (4)
 4.4       A 16 kVA star-connected generator is used to power a three-phase load. The
           phase voltage is 220 V and the phase angle is 29,54°.
           Given:
           S         = 16 kVA
           VPH       = 220 V
           θ         = 29,54°
           Calculate the following:
           4.4.1       Line voltage                                                                (3)
           4.4.2       Line current at full load                                                   (3)
           4.4.3       Active power                                                                (3)
           4.4.4       Reactive power                                                              (3)
 4.5       The input power to a three-phase system is 3,45 kW. The system is able to
           deliver 3,2 kW of effective power on the output. Calculate the efficiency of the
           system.                                                                                 (3)
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Electrical Technology: Power Systems                  10                DBE/November 2025
                                                NSC Confidential

 4.6       FIGURE 4.6 below shows the connection of an analogue wattmeter to one of
           the phases of a three-phase load. Answer the questions that follow.

                                            Wattmeter1
                        L1
                                           Coil A

                                                             R        Load1
                                           Coil B

                         N

                             FIGURE 4.6: WATTMETER CONNECTION

           4.6.1      Identify coil A in FIGURE 4.6 above.                                      (1)

           4.6.2      Explain TWO advantages of digital wattmeters compared to
                      analogue wattmeters.                                                      (2)

           4.6.3      Describe the function of coil B in FIGURE 4.6 above.                      (2)

 4.7       FIGURE 4.7 below shows how a power factor meter is connected to a
           three-phase balanced load network. Answer the questions that follow.

                                       V-coil

                                                    I-coil

                                                                        R
                                                                        Y
                                                                        B

                       FIGURE 4.7: POWER FACTOR METER CONNECTION

           4.7.1      Name TWO disadvantages of having a low power factor.                      (2)

           4.7.2      Explain the purpose of a power factor meter.                              (1)

           4.7.3      Describe how current is affected in a system when the load has a
                      low power factor compared to the same load with a higher power
                      factor. Motivate your answer.                                             (2)
                                                                                                [35]

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Electrical Technology: Power Systems          11                           DBE/November 2025
                                        NSC Confidential

 QUESTION 5: THREE-PHASE TRANSFORMERS

 5.1       Explain mutual inductance as the principle of operation of transformers.               (2)

 5.2       Refer to FIGURE 5.2 below and answer the questions that follow.

                               A1             A2            A3

                                         B1            B2           B3

                            FIGURE 5.2: THREE-PHASE TRANSFORMER

           5.2.1      State the configuration in which coils A1–A3 and B1–B3 are
                      connected.                                                                  (2)

           5.2.2      Explain why an iron core is used in the construction of a transformer.      (3)

           5.2.3      State if FIGURE 5.2 above represents a core type or a shell type
                      transformer. Motivate your answer.                                          (2)

           5.2.4      Explain how dry type transformers dissipate heat when operating.            (1)

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Electrical Technology: Power Systems         12                          DBE/November 2025
                                       NSC Confidential

 5.3      Refer to FIGURE 5.3 below and answer the questions that follow.

                           L1                                           L1

                                       R                   B

                           L2                                           L2

                                       Y                   Y

                           L3                                           L3

                                       B                   R
                                                                        N

           FIGURE 5.3: THREE SINGLE-PHASE TRANSFORMERS CONNECTED AS
                           A THREE-PHASE TRANSFORMER
          5.3.1       Name ONE characteristic that must be identical in all three
                      transformers for it to be used as a three-phase unit.                     (1)
          5.3.2       Name ONE application of the configuration used in FIGURE 5.3
                      above.                                                                    (1)
          5.3.3       Explain the advantage of three single-phase transformers connected
                      as a single three-phase unit when one set of coils is damaged.            (2)
 5.4       A three-phase transformer with a primary connected in delta and the secondary
           connected in star has a primary line voltage of 6 600 V. The secondary line
           voltage is 380 V. The transformer has an efficiency of 100%.
          Given:
          VL1 = 6 600 V
          VL2 = 380 V
           η = 100%

         5.4.1        Determine the primary phase voltage.                                      (2)

         Calculate the following:
         5.4.2        Secondary phase voltage                                                   (3)

         5.4.3        Turns ratio                                                               (3)

         5.4.4        The primary phase current if the secondary line current is 900 A          (3)
 5.5     A three-phase transformer powers a load of 4 500 W. The efficiency of the
         transformer is 96%. Calculate the total losses of the transformer in watts.            (3)
 5.6     Describe the function of the conservator during the operation of transformers.         (2)
                                                                                                [30]

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Electrical Technology: Power Systems                             13                       DBE/November 2025
                                                           NSC Confidential

 QUESTION 6: THREE-PHASE MOTORS AND STARTERS

 6.1       Name TWO electrical tests to be conducted on a three-phase motor.                                     (2)

 6.2       Explain reactive power with reference to a three-phase induction motor.                               (2)

 6.3       Refer to FIGURE 6.3 below and answer the questions that follow.

                                                                                    B

           % of full load torque
                                   200       A
                                                     Pull-up
                                                     torque

                                   100

                                                                                                No-load
                                                                                                 speed

                                         0                  50                          100
                                                       % of speed

                                   FIGURE 6.3: SPEED VERSUS TORQUE CHARACTERISTIC CURVE

           6.3.1                         Label A and B on the characteristic curve in FIGURE 6.3 above.          (2)

           6.3.2                         State whether the slip is minimum or maximum at no-load speed.          (1)

 6.4       The rotor of a three-phase induction motor with 2 pole pairs per phase rotates
           at 1 250 r/min when connected to a 400 V/50 Hz supply.

           Given:

           VL                       = 400 V
           f                        = 50 Hz
           nr                       = 1 250 r/min
           p                        =2

           Calculate the following:

           6.4.1                         Synchronous speed of the motor                                          (3)

           6.4.2                         Percentage slip                                                         (3)

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Electrical Technology: Power Systems         14                           DBE/November 2025
                                       NSC Confidential

 6.5       A three-phase induction motor is able to deliver 4 kW of output power at full
           load. The motor has a power factor of 0,85 and draws a line current of 6,8 A
           from the supply at full load.

           Given:
           POUT       = 4 kW
           IL         = 6,8 A
           pf         = 0,85
           Assume that there are no losses and calculate the following:
           6.5.1      Phase angle                                                               (3)
           6.5.2      Supply voltage                                                            (3)

           6.5.3      Apparent power                                                            (3)
           6.5.4      Reactive power                                                            (3)

 6.6       The circuit in FIGURE 6.6 below is used to control a three-phase motor. The
           motor must be able to rotate in a forward direction and in a reverse direction,
           but NOT at the same time. Answer the questions that follow.

                      L
                           OL
                           N/C

                          STOP

                       START                               START
                         1                                   2               MC2
                                          (A)
                                                                             N/O1

                          N

                       FIGURE 6.6: FORWARD-REVERSE CONTROL CIRCUIT

           6.6.1      Label A in FIGURE 6.6 above.                                              (1)

           6.6.2      Explain the condition that will open OL N/C during the operation of
                      the circuit.                                                              (1)

           6.6.3      Explain the need for having TWO main contactors in the circuit.           (2)

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Electrical Technology: Power Systems         15                        DBE/November 2025
                                       NSC Confidential

           6.6.4      Name the connection needed to prevent the simultaneous forward
                      and reverse operation of the motor.                                     (1)

           6.6.5      Redraw and complete in your ANSWER BOOK the control circuit for
                      FIGURE 6.6, on the previous page, that satisfies the requirements
                      of QUESTION 6.6.                                                        (4)

           6.6.6      State how a faulty stop button, that remains permanently open,
                      would affect the operation of the circuit.                              (1)
                                                                                              [35]

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Electrical Technology: Power Systems             16                    DBE/November 2025
                                           NSC Confidential

 QUESTION 7: PROGRAMMABLE LOGIC CONTROLLERS (PLCs)

 7.1       Refer to FIGURE 7.1 below of the programmed scan cycle of a PLC and answer
           the questions that follow.

                                                       A

                                OUTPUT                          B
                                 SCAN

                                       FIGURE 7.1: PLC SCAN CYCLE

           7.1.1      Label A and B.                                                         (2)

           7.1.2      Explain the output scan.                                               (2)

 7.2       State TWO advantages of a PLC system over a hardwired relay system, with
           reference to cost.                                                                (2)

 7.3       Explain why the PLC wiring and connections must be checked before switching
           on.                                                                               (2)

 7.4       Explain why a PLC system is safer than a hardwired system when a fault
           condition occurs.                                                                 (2)

 7.5       State the purpose of the following PLC program functions:

           7.5.1     Markers/Flags                                                           (2)

           7.5.2     Contactor                                                               (2)

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Electrical Technology: Power Systems             17                     DBE/November 2025
                                           NSC Confidential

 7.6       Refer to FIGURE 7.6 below and answer the questions that follow.

                                       A                      Output

                                       B

                                 FIGURE 7.6: PLC LOGIC FUNCTION

           7.6.1      Draw the equivalent logic symbol of FIGURE 7.6 above.                     (3)

           7.6.2      Complete the truth table in TABLE 7.6.2 below by writing down only
                      the state of the output in the ANSWER BOOK.

                                  A                      B              OUTPUT
                                  0                      1                (X)
                                  1                      1                (Y)
                                                     TABLE 7.6.2                                (2)

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Electrical Technology: Power Systems           18                      DBE/November 2025
                                         NSC Confidential

 7.7       FIGURE 7.7(A) below shows the relay diagram of a manual sequence starter.
           Redraw and complete the PLC ladder logic diagram in FIGURE 7.7(B), that will
           execute the same function in a PLC system, in the ANSWER BOOK.

                     L

                     STOP                    MC1N/O2

                 OL1N/C                                     OL2N/C

                START                                  START
                                          MC1N/O                             MC2N/O
                 MC1                                    MC2

                                   MC1                               MC2
                     N

          FIGURE 7.7(A): CONTROL CIRCUIT OF A MANUAL SEQUENCE STARTER

                     STOP

                                                                                              (9)
                                            FIGURE 7.7(B)

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Electrical Technology: Power Systems              19                          DBE/November 2025
                                            NSC Confidential

 7.8      FIGURE 7.8 below shows the characteristic curves of the VSD when it is used to
          control the speed of a three-phase induction motor. Study the characteristic curves
          and answer the questions that follow.

             TORQUE
                400%

                300%                                                             Available
                                                                               load range of
                200%                                                             the VSD

                100%

                               20%          40%     60%         80%       100% SPEED
                                             FIGURE 7.8A
                                             FIGURE 7.8(A)
             TORQUE
               400%
                                                                 VSD design
                   300%
                                                                      Fixed frequency
                                                                      motor design
                   200%

                   100%
                       100%          200%      300%      400%           CURRENT
                                            FIGURE 7.8(B)
                                            FIGURE  7.8B

                            FIGURE 7.8: VSD TORQUE VERSUS SPEED AND
                                TORQUE VERSUS CURRENT GRAPHS

           7.8.1          Compare the characteristics in FIGURE 7.8(B) above and state the
                          improvement a VSD motor design has compared to a fixed
                          frequency motor design.                                                   (2)

           7.8.2          Refer to FIGURES 7.8(A) and 7.8(B) above and state TWO
                          advantages for industries and manufacturers when using a VSD to
                          control the speed of a motor.                                             (2)

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Electrical Technology: Power Systems      20                           DBE/November 2025
                                       NSC Confidential

 7.9       Name the component used to dissipate the excessive energy during the
           process of regenerative braking.                                                (1)

 7.10      Name THREE applications of a VSD.                                               (3)

 7.11      Explain how the three-phase AC supply is changed to DC, with reference to the
           first stage in a VSD.                                                           (2)

 7.12      Explain how longer ON times affect the output frequency of a VSD during the
           process of pulse width modulation (PWM).                                        (2)
                                                                                           [40]

                                                                               TOTAL:      200

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Electrical Technology: Power Systems                                                  DBE/November 2025
                                                NSC Confidential

                                             FORMULA SHEET
RLC CIRCUITS                                          THREE-PHASE AC GENERATION
P = V I Cos θ                                              STAR
XL = 2πfL                                                  VL = �3 VPH
         1                                                 VPH = IPH ZPH
XC =
       2πfC                                                IL = IPH
           1                      f 1 + f2
   fr =              OR    fr =                            DELTA
        2π√LC                        2
        fr
BW =                 OR    BW = f2 - f1                    VL = VPH
        Q
SERIES                                                     VPH = IPH ZPH
VR = IR                                                    IL = �3 IPH
VL = IXL                                                   POWER
VC = IXC                                                   S�Papp � = �3 VL IL

       VT                                                  Q(Pr ) = �3 VL IL Sin θ
IT =              OR       IT = IR = IC = IL
       Z                                                   P = �3 VL IL Cos θ
                                                                   P
Z = �R2 + (XL - XC )2                                      Cos θ =
                                                                   S
             2
VT = �VR + (VL - VC )2         OR            VT = IZ       EFFICIENCY
            R                                     VR            POUT
Cos θ =                   OR           Cos θ =             η=        × 100
            Z                                     VT             PIN
       XL XC VL VC 1    L
Q=       =   =   =  = �
       R   R   VT VT R C                                   TWO-WATTMETER METHOD

PARALLEL                                                   PT = P1 + P2
VT = VR = VC = VL
                                                                          P1 - P2
     VT                                                    Tan θ = �3 �           �
IR =                                                                      P1 + P2
      R
     VT
IC =                                                       THREE-WATTMETER METHOD
     XC
     VT
IL =                                                       PT = P1 + P2 + P3
     XL
        2
IT = �IR + (IL - IC )2
       VT
Z=
       IT
            IR
Cos θ =
            IT
       R   R
Q=       =
       XL XC

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### Page 22

Electrical Technology: Power Systems

DBE/November 2025

NSC Confidential

THREE-PHASE TRANSFORMERS

THREE-PHASE MOTORS AND STARTERS

STAR

V_= 73 Vex
IL= ley

DELTA
VL= Vex

IL =V3 lpn

POWER

S(Papp) = V3 Vi I
Q(P,) = V3 V, ISin 8
P=/3V, |, Cos 0

Cc =e
os O= =

Veu(ay — Ni _ lpr)

VeH(2) Neo lpyqy

. Ny
Turns ratio: TR= —
No

EFFICIENCY

- Pour
"> Bou; + losses ~ 100

STAR

V_= V3 Vex
IL = ley

DELTA
ViL= Vex

IL =V3 lpn

POWER

S(Papp) = V3 Vi Ik
a(P,) = V3 V, I,Sin 8
P= /3V, |, Cos 9
P= /3V, |, Cos On

Cc =e
os O= =

EFFICIENCY
_ Pin- losses
Pin

n= Pour
Pout + losses

x 100

x 100

Pout
= x 100
Pin

SPEED

| h
(pole pairs) p = poles per phase

2
60 f
n=
n,-n,
Per unit slip = ——
ns
ng-n
% slip = ae x 100

Ss
n, =ns(1 - % slip)
Slip = ng - Nn;

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