EEM 5 Three-phase Multifunction Machines (English)

Course "EEM 5 Three-phase Multifunction Machines" Machines"

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EEM5 Three-phase multifunction maschines Training objectives Equipment 300 W Classic Line Safety Asynchronous motor (Three-phase multifunction machine) Connection and starting Rotation reversal Operating points

Synchronous motor (Three-phase multifunction machine) Connection and starting Rotation reversal Phase-shifter operation V-characteristics

Synchronous generator (Three-phase multifunction machine) Connection and starting Load characteristics

Mains synchronisation (Three-phase multifunction machine) Synchronisation to the mains Power feed (Classic Line)

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EEM5 Three-phase multifunction maschines

EEM5 Three-phase multifunction maschines Training objectives

Welcome to the Three-phase Multifunction Machine Course! The LUCASNÜLLE team wishes you lots of fun and success in completing the course subjects and performing the experiments. The following pages provide you with an overview of the course content and required equipment. In this course we will be working on acquiring practical know-how and experience working with the three-phase multifunction machine. Experiment-based investigations of the asynchronous and synchronous motor and generator are at the focal point of our work and provide us with insight into the machine's function, operaton and operating response.

Training objectives        

  

Motor and generator operating modes Nominal data and rating plate Asynchronous and synchronous operation Phasen-shifter operation (synchronous motor) V-characteristics Measurement of the phase-to-phase and line-to-line variables Rotation reversal Load characteristics for the asynchronous and synchronous motor as well as synchronous generator Phase-shifter operation Mains synchronisation Power measurement and synchronised generator

Prerequisites   

Fundamentals of electrical machines Fundamentals of electricity and electrical engineering How to work with measuring instruments

EEM5 Three-phase multifunction maschines Training objectives

EEM5 Three-phase multifunction maschines Equipment 300 W Classic Line

EEM5 Three-phase multifunction maschines Safety Basic safety instructions

In all experiments using mains voltages high, life-threatening voltages arise. For that reason use only safety measurement leads and make sure that there are no shortcircuits.

It is imperative that all of the devices, which are provided with an earth or where earthing is possible, must be earthed. This is particularly the case for the frequency converter being used.

Always be very careful to check the wiring of the application modules and only switch on the mains voltage after a check has been completed. Whenever possible use a robust current monitoring instrument in the circuit.

Always use shaft-end guards and coupling guards as protection against contact with rotating motor parts

All locally applicable stipulations and standards governing how electrical equipment is handled must be complied with.

EEM5 Three-phase multifunction maschines Safety

General instructions on handling the equipment 

 







Check that the knurled screws at the base of the motor and the coupling sleeves (power grip) on the motor shaft are all securely fastened. Use shaft and coupling guards. Any prolonged running of the machines when operating under high loads can subject the machines to excessive heating. The extreme case of the machine being prevented from rotating entirely may only arise briefly. All of the machines are equipped with a thermal circuit-breaker, which triggers when the maximum permissible operating temperature is exceeded. These switching contacts are accessible on the terminal board and must always be connected to the corresponding connection sockets of the mains supply and control unit. All measurements have been recorded using conventional measuring instruments (primarily class 1.5) at the standard mains voltage (230/400V +5% -10% 50Hz) using standard production machines. Experience suggests that measurements will lie within the tolerance range of +/-15% with respect to the specified measurement. For more information on this please refer to VDE0530.

EEM5 Three-phase multifunction maschines Asynchronous motor (Three-phase multifunction machine)

Asynchronous motor (slip-ring rotor) You will be performing exercises on the following exericises on the "asynchronous motor" on the next few pages (slip-ring rotor)":

  

Connection and starting Rotation reversal Load characteristics



Training content: "Connection and starting"   

   

Identify the terminals of the motor Register the nominal data of the motor using the rating plate Put the three-phase multifunction machine into operation as an asynchronous motor Measure the motor voltage and the motor current Measure the rotor standstill voltage Put the motor into operation with the brake Subject the motor to load

Enter the nominal data of the three-phase multifunction machine

____W UN star connection ____V IN star connection ____ A Rated power

____ cos φasynchronous ____

correct!

cos φsynchronous

correct!

Synchronous speed ____min-1

Frequency ____Hz Uexc. DC Iexc. DC

____V ____ A

correct!


Setup instructions: "Connection and Starting" 



Set up the circuits in accordance with the following circuit and assembly plans Switch on the brake as well, this does not subject the motor to any load

Additional information on the brake can be found in the corresponding (online) documentation Make sure the the ammeter/voltmeter is connected up correctly

"Connection and starting" circuit diagram


"Connection and starting" assembly diagram

Putting the asynchronous motor into operation and recording a load characteristic (Ra= (Ra=0 0 Ω) Required settings:  

Brake: Mode "Torque Control" Starter: 0 Ohm

EEM5 Three-phase multifunction maschines Asynchronous motor (Three-phase multifunction machine) Experiment procedure:    

Put the motor into operation and observe it Brake the motor using the torque values specified in the t he table At the same time measure measure the motor current and speed speed Enter the measured values into the table

M/Nm n/(1/min) I/A

0.3

0.6

0.9

1.2

1.5

1.8

Which of the following statements are correct regarding the recorded load characteristic? Motor current, voltage and torque drop as the speed decreases If the load increases the motor current rises proportionally

correct!

2.1


Put the asynchronous motor back into operation and record an additional load characteristic (M=const.) Required settings:  

Brake: Mode "Torque Control" Constant torque (see Table)

Experiment procedure: 

  

Put the motor into operation and set constant torque levels to the brake which can be taken from the table Set the starter values using the ones specified in the table Then take measurements of the motor current and speed Enter the measured values into the table

M=2Nm

Ra/Ohm n/(1/min) I/A

0

2

5

10

20


Which of the following statements regarding the load characteristic are correct? Due to the constant load torque M the motor current remains practically unchanged The speed changes only slightly for rising starter values The speed drops with rising starter values With higher starter values the speed drops minimally, the motor current remains constant

correct!

EEM5 Three-phase multifunction maschines Asynchronous motor (Three-phase multifunction machine) Recording several load characteristics with the "ActiveDrive / ActiveServo" software

Experiment procedure:   



   

Start the "ActiveDrive / ActiveServo" software Select automatic "speed control" setting The motor is to be braked in 20 steps down to standstill ( Note: enter the corresponding number of steps into "ActiveDrive / ActiveServo" under "Settings" -> "Setpoints" -> "Ramp"!) The respective load characteristics of the asynchronous machine are to be recorded for a total of four starter resistance values (see table) (only 1 kW: maintain a pause of 40 s between the individual measurements in order to refrain from overheating the starter resistors) Begin with the lowest starter resistance value (0 Ohm) All of the load characteristics are recorded in one graph Label and scale the graph in accordance with the space provided for the diagram The following parameters are to be recorded: Torque M(n) Export the graph created after successfully completing the measurement and place it into the corresponding space reserved for it below Save the settings used in the "ActiveDrive / ActiveServo" software for later experiments under the file name "eem5_loadcharacteristic" 

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

EEM5 Three-phase multifunction maschines Asynchronous motor (Three-phase multifunction machine) Space reserved for load characteristic

Which statements below are correct in terms of the four load characteristics recorded? As the resistance drops the pull-out torque shifts towards the breakaway torque Since the rotor resistance is increased by the starter resistance, the current drops off both on the primary side (stator winding) as well as on the secondary side (rotor winding) of the motor The pull-out torque is shifted towards the breakaway torque with increasing starter resistance. The phase-shift between the current and voltage becames greater and greater With increasing starter resistance the pull-out torque is shifted toward the breakaway torque. The phase-shift between voltage and current diminishes more and more

correct!

EEM5 Three-phase multifunction maschines Asynchronous motor (Three-phase multifunction machine) Measurement of the rotor standstill voltage Experiment procedure:   

Modify the circuit connection in accordance with the following circuit diagram Then switch on the power supply for the stator winding Measure the rotor voltage Urotor

"Connection and starting (rotor standstill voltage)" circuit diagram


"Connection and starting (rotor standstill voltage)" assembly diagram


How high is the measured rotor standstill voltage Urotor ? Urotor ____V

correct!

What causes the rotor standstill voltage? A voltage is induced in the measurement leads which is detected and displayed on account of the high input impedance of the measuring instrument The stator winding induces a voltage in the winding of the rotor making the motor act like a transformer

correct!



Training content: "Rotation reversal"  

Distinguish the difference between clockwise and anticlockwise operation Put the motor into operation in both rotation directions

Definition of rotation direction If you look at the drive shaft end of the machine from the perspective of the working machine (in our case the brake), the rotating direction is positive when it is clockwise. If the motor has two workable shaft ends, then it is the shaft end opposite the cooling vents, collector or slip-rings that is the shaft end which defines the rotation direction.


Assembly instructions: "Rotation reversal" 



Assemble the circuits according to the following circuit and assembly diagrams Also switch on the brake as this does not subject the motor to any load

Additional information on the brake can be found in the corresponding onlinedocumentation

"Rotation reversal" circuit diagram"


"Rotation reversal" assembly diagram

Rotation reversal Experiment procedure: 

Switch the motor on and observe it

What is the motor's rotation direction? The motor rotates clockwise The motor rotates anticlockwise

correct!

EEM5 Three-phase multifunction maschines Asynchronous motor (Three-phase multifunction machine)  

Switch off the motor and modify the circuit in accordance with the circuit diagram Put the motor into operation and observe it again

"Rotation reversal" circuit diagram



correct!

What is the correct method to reverse rotation direction? Interchange the terminals for the rotor winding Interchange any random two terminals of the stator winding Only interchange L2 & L1 on the stator winding

correct!



Training content: "Operating points" 

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Simulation of various loads (load machines) using the "ActiveDrive / ActiveServo" software Settting the software parameters using the load specific default values (load constants and load torque) Recording several operating points for various starter resistance values Recognising how the motor responds to different loads


Assembly instructions: "Operating points" 



Set up the circuits in accordance with the following circuit and assembly diagrams Switch the brake on to, this does not subject the motor to any load

More detailed information on the brake and the software being used can be found in the corresponding online documentation Make sure that the ammeter/voltmeter are connected correctly

"Operating points" circuit diagram


"Operating points" assembly diagram


Recording the operating points using the simulated load "Pump/Ventilator" with the "ActiveDrive / ActiveServo" software Required settings: 

Brake: Industrial line: "PC Mode" Classic line: "PC Mode" The following settings are to be carried out subsequently in the "ActiveDrive" / "ActiveServo" software: Load machine: "Pump / Ventilator" Load constant: see experiment procedure Under the "View" => "Measured value display" mark down all of the mechanical and electrical variabels with the exception of the slip  



  

Important: Between the individual measurements on the 1 kW machine breaks of 40s each are to be carried out, to avoid overheating the resistors.

Experiment procedure: 

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Start the "ActiveDrive / ActiveServo" software and first open the file "eem5_loadcharateristic" (see "connection and starting") The make the required settings The following parameters are to be recorded during this measurement: Torque M(n) Put the motor into operation and set the starter to 0 Ohm Commence the measurement and slowly increase the load constant "I" until the power level P2 shown in the parameter dialog corresponds to the rated power of the motor and then save this first "operating point" Now vary the starter value according to the specified values, waiting a moment each time and then saving the additional operating points Export the created graph after successful measurement and replace the corresponding space holder set aside for it below Save the settings under the filename "eem5_Pump-Ventilator" 

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Additional information pertaining to the load machine "Pump/ Ventilator" and the definition of load constants "I" can be found in the online documentation of the "ActiveDrive / ActiveServo" software

EEM5 Three-phase multifunction maschines Asynchronous motor (Three-phase multifunction machine) Space holder for the load characteristic "Pump Ventilator"

How would you describe the characteristic curve of the load torque of the load machine Pump/Ventilator? Linear Quadratic Cubic

correct!

What is the magnitude of the load constant "I" when the motor is operating under nominal power? I= ____

correct!


EEM5 Three-phase multifunction maschines Synchronous motor (Three-phase multifunction machine)

Synchronous motor (slip-ring rotor) On the next pages you will be performing the following exericises on the "synchronous motor (slip-ring rotor)":

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Connection and starting Rotation reversal Phase-shifter operation V-characteristics (stability limits)



Training content: "Connection and starting"  

     

Recognise the motor terminals Put the three-phase multifunction machine into operation as a synchronous motor Measure the motor voltage and the motor current Measure the exciter current Put the motor into operation using different exciter currents Put the motor into operation with the brake Subject the motor to load Determine the "pull-out torque"


Assembly instructions: "Connection and starting"  

Set up the circuits according to the circuit and assembly diagrams Switch on the brake too as this does not subject the motor to any load

More detailed information on the brake can be found in the corresponding online documentation Make sure the ammeter/voltmeter are connected correctly




Putting the synchronous motor into operation and recording the load characteristics at varying excitation Required settings:  

Brake: Mode "Torque Control" Exciter unit: see tables

EEM5 Three-phase multifunction maschines Synchronous motor (Three-phase multifunction machine) Experiment procedure:      

Put the motor into operation and observe it Brake the motor using the torque levels specified in the tables The respective exciter current to be set is taken from the appropriate table Measure the motor current "I" and the speed "n" Enter the measured values into the tables As soon as the motor loses "synchronisation", it should be immediately switched off, and all measured values for the motor current are to be ignored from this point on

First switch on the stator winding, wait a moment until the motor has started and only then is the rotor winding, i.e. the exciter device connected Ierr.=0,75 A

M/Nm n/(1/min) I/A

0.1

0.2

0.3

0.4

0.5


Ierr.=1,5 A

M/Nm

0.10

0.50

0.75

1.00

1.25

n/(1/min) I/A

Ierr.=3 A

M/Nm n/(1/min) I/A

0.1

0.5

1.0

1.5

2.0

2.5

EEM5 Three-phase multifunction maschines Synchronous motor (Three-phase multifunction machine) Enter the pull-out torque values determined for the appropriate exciter currents at which the motor loses synchonisation! M = ____Nm M ullout second measurement = ____Nm correct! M ullout third measurement = ____Nm

Which of the following statements are correct? The increase in exciter current causes a shift of the pull-out torque to higher torques When the load is too extreme, only the speed falls, while the motor continues to operate with rated power The increase in the exciter current causes a shift of the pullout torque to lower torques When the load is too extreme the synchronous motor loses synchronisation

correct!


Training content: "Rotation reversal"  

Recognise the distinction between clockwise and anticlockwise rotation Operate the motor in both rotation directions

Definition of rotation direction If you look at the drive shaft end of the machine from the perspective of the working machine (in our case the brake), the rotating direction is positive when it is clockwise. If the motor has two workable shaft ends, then it is the shaft end opposite the cooling vents, collector or slip-rings that is the shaft end which defines the rotation direction.


Assembly instructions: "Rotation reversal" 




Additional information on the brake can be found in the corresponding onlinedocumentation



"Rotation reversal" assembly diagram

Rotation reversal Experiment procedure: 

Switch the motor on and observe it


correct!

EEM5 Three-phase multifunction maschines Synchronous motor (Three-phase multifunction machine)  

Switch off the motor and modify the circuit in accordance with the circuit diagram Put the motor into operation and observe it again




correct!

What is the correct method to reverse rotation direction? Reverse the exciter voltage polarity Interchange any random two terminals of the stator winding

correct!



Training content: "Phase-shifter operation" 

  

Putting the three-phase multifunction machine into operation as a synchronous motor in phase-shifter mode Generation of under- and overexcitation using the exciter unit Recognise that the synchronous motor is able to absorb reactive power Measure the power factor as a function of the exciter current


Assembly instructions: "Phase-shifter operation" 



Assemble the circuits according to the following circuit and assembly diagrams Also switch on the brake as this does not subject it to any load

More detailed information can be found in the corresponding online documentation

"Phase-shifter operation" circuit diagram


"Phase-shifter operation" circuit diagram

Putting the synchronous motor into operation as a phase-shifter Required settings:  

Brake: "Torque Control" mode Constant torque (see tables)

EEM5 Three-phase multifunction maschines Synchronous motor (Three-phase multifunction machine) Experiment procedure: 

  

Put the motor into operation and set the brake to a constant torque level to be taken from the following tables Vary the excitation using the preset values in the tables Make sure to also measure the power factor cos φ Enter the measured values into the tables

Make sure that the ammeter/voltmeter are connected correctly!

M=0,1 Nm

+pf

-pf

Ierr./A cos φ

1.0

2.0

3.0

4.0


M=0,5 Nm

Ierr./A cos φ

1.0

2.0

3.0

4.0

M=1,0 Nm

Ierr./A cos φ

1.5

2.0

3.0

4.0


Which type of excitation leads to the generation of inductive or capacitive reactive power? At underexcitation capacitive reactive power is generated At overexcitation capacitive reactive power is generated At overexcitation inductive reactive power is generated At underexcitation inductive reactive power is generated

correct!

If you wanted to use the synchronous motor as a reactive power compensator in the power mains, which of the listed correlations of mains load and excitation type would be correct? In mains with strong inductive loading the synchronous motor is operated with overexcitation as phase-shifter In the case of strong capacitive mains loading the synchronous motor is operated with overexcitation as a phase-shifter In mains under strong inductive loads the synchronous motor is operated with underexcitation as a phase-shifter In the case of strong capacitive mains loading the synchronous motor is operated with underexcitation as a phase-shifter

correct!


Training content: "V-characteristics" 

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Putting the three-phase multifunction machine into operation as a synchronous motor Recording the characteristics I = f (Iexc.) (V-characteristics) Recognising that the exciter current changes proportionally to the load Determination of the stability limits of the synchronous motor Measurement of the motor and exciter current

Assembly instructions: "V-characteristics" 




More detailed information on the brake and the software being used can be found in the corresponding online documentation


"V-characteristics" circuit diagram


"V-characteristics" diagram

Putting the synchronous motor into operation and recording the V -characteristics Required settings:  

Brake: "Torque Control" mode Exciter unit: see table

EEM5 Three-phase multifunction maschines Synchronous motor (Three-phase multifunction machine) Experiment procedure:     

Brake the motor using the torques specified in the table Begin with the lowest torque and respectively the highest exciter current The exciter current to be set can also be taken from the table Measure the motor current and enter the measurement results into the table As soon as the motor falls out of synchronisation, it is switched off and all of the measured values taken after this point in time for the motor current are ignored

M=0,6Nm M=1,2Nm M=1,8Nm

Ierr./A Imot./A Imot./A Imot./A

1.0

1.5

2.0

2.5

3.0

3.5

At which excitation level does the motor generate capacitive reactive power? During underexcitation During overexcitation

correct!

4.0

EEM5 Three-phase multifunction maschines Synchronous motor (Three-phase multifunction machine) How does the synchronous motor respond when the exciter current is lowered to below the stability limit? The speed does not change to any noticeable degree The motor falls out of synchronisation The torque increases more and more and the motor begins running rougher and rougher When the stability limit is fallen below the speed drops off severely

correct!


EEM5 Three-phase multifunction maschines Synchronous generator (Three-phase multifunction machine)

Synchronous generator (slip-ring rotor) On the next pages the following exercises will be performed on the "synchronous generator (slip-ring rotor)":

  

Connection and starting Load characteristics Mains synchronisation



Training content: "Connection and starting" 





Putting the three-phase multifunction machine into operation as a synchronous generator Measuring the generator voltage at constant speed and variable exciter current Measure the generator voltage at constant excitation and variable speed

Assembly instructions: "Connection and starting" 



Assemble the circuits according to the following circuit and assembly diagrams Also switch on the brake as this does not subject the machine to any load

More detailed information on the brake can be found in the corresponding online documentation Make sure that the ammeter/voltmeter are connected correctly




Putting the synchronous generator into operation and measuring the generator voltage at varying excitaion and constant speed Required settings:  

 

Brake: "Speed Control" mode Speed: Synchronous speed (see nominal data of the three-phase multifunction machine) Rotation direction of the brake: positive rotation direction Exciter unit: see table

EEM5 Three-phase multifunction maschines Synchronous generator (Three-phase multifunction machine) Experiment procedure:  

   

Operate the brake as the drive motor for the synchronous generator Put the brake into operation and set the speed setting to synchronous speed for the three-phase multifunction machine The respective exciter current is to be taken from the table Measure the respective generator voltage "U2" for the exciter currents Enter the measured values into the table Also observe the torque produced by the drive motor

Ierr./A U2/V

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

At which exciter current does the synchronous generator achieve nominal voltage Iexc.= ____ A

correct!


How does the drive motor's torque respond and why does it respond in this way? At a lower exciter current a higher voltage can be induced in the rotor circuit which increases the torque of the drive motor (brake) If the exciter current increases, the rotor's magnetic field becomes stronger, which results in an increase in the required torque If the exciter current is reduced the generator also absorbs less electrical energy resulting in an increase in the required torque If the exciter current is lowered the generator also absorbs less mechanical energy, and the required torque falls

correct!

Put the synchronous generator into operation and measure the generator voltage at variable speed and constant excitation Required settings:    

Brake: "Speed Control" mode Speed: see table Rotation reversal of the brake: positive rotation direction Exciter device: see table

Experiment procedure:    

Operate the brake as a drive motor for the synchronous generator Put the brake into operation and take the speed values from the table The exciter current levels are also taken from the table Measure the corresponding generator voltage "U2" for each value


Ierr.=3A

n/(1/min) U2/V

500

750

1000

1250

1500



Training content: "Load characteristics" 



Putting the three-phase multifunction machine into operation as a synchronous generator Measure the generator voltage at constant excitation and speed under variable load


Assembly instructions: "Load characteristics" 



Assemble the circuits according to the following circuit and assembly diagrams Also switch on the brake as this does not subject the machine to any load

More detailed intormation on the brake can be found in the online documentation Make sure that the ammeter/voltmeter are connected correctly

"Load characteristics" circuit diagram


"Load characteristics" circuit diagram

Recording the load characteristics at constant excitation and speed Required settings:  

  

Brake: "Speed Control" mode Speed: Synchronous speed (see nominal data of the three-phase multifunction machine) Rotation reversal of the brake: positive rotation Exciter device: see table Load resistance: see table

EEM5 Three-phase multifunction maschines Synchronous generator (Three-phase multifunction machine) Experiment procedure:  

  

Operate the brake as drive motor for the synchronous generator Put the brake into operation and set the speed of the three-phase multifunction machine to synchronous speed Begin with the lowest value for the load resistor Each respective value to be set for the load resistance can be taken from the table Measure here the following variables: Generator voltage "U" Generator current "I" Generator apparent power "S" Enter the measured values into the table Only motor ...-3W: Bear in mind that for the specified resistance values in the table that there is always one non-adjustable 1 kΩ resistor connected in series to the variable resistor. The values are to be set accordingly at the variable resistor minus 1 kΩ.   

 

Ierr.=3A Ra/Ohm 2000 1500 1300 1200 1100

I/A

U/V

S/VA


Which of the following statements are true for the load characteristics? When the generator is under load the generator voltage increases only slightly The apparent power is constant independent of the load When the generator is under load the generator voltage drops only slightly The generated apparent power increases linearly with increasing generator load

correct!


EEM5 Three-phase multifunction maschines Mains synchronisation (Three-phase multifunction machine)

Mains synchronisation On the next pages the following exercises will be carried out on the "synchronous generator (slip-ring rotor)":



Fundamentals Learn various methods to determine the point of synchronisation 



Advanced Generation of capacitive and inductive reactive power Measure the generator power at variable drive power  



Training content: "Synchronisation to mains" 

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



Putting the three-phase multifunction machine into operation as a synchronous generator Mains synchronisation with the aid of the bright, dark and threelamp method Mains synchronisation using double frequency and doublevoltage meter and synchronoscope i.e. zero-voltage meter Determination of the synchronisation time point

Assembly instructions: "Synchronisation to the mains" 



Set up the circuits according to the following circuit and assembly diagrams Also switch the brake on as this does not subject the machine to any load

More detailed information on the brake can be found in the corresponding (online) documentation


"Mains synchronisation (dark method)" circuit diagram


"Mains snchronisation (dark method)" assembly diagram

Mains synchronisation on the local power network using different methods All synchronisation methods require the utmost care and attention! The generator may under no circumstances be switched asynchronously on line! The STM brake of the Industrial Line only partially supports the mains synchronisation mode. If the STM brake is operated at 1,500 rpm, but differs slightly from the mains frequency generated by the driven generator. This fault increases with each rotor r otation and ultimately develops into an ever stronger deviation between the generated frequency and the mains frequency. What is distinguishable here is that the torque which is needed slowly increases. To that extent it is necessary to cease synchronisation after a few seconds in order to avoid submitting the generator and the STM brake to excessive load.

Required settings (all methods):

EEM5 Three-phase multifunction maschines Mains synchronisation (Three-phase multifunction machine) 

  

Brake: "Speed Control" for the STM brake i.e. "Synchronisation & Speed Control" for the servo brake Speed: Preset synchronous speed using the control knob Rotation direction of the brake: clockwise rotation direction Exciter device: nominal excitation of the three-phase multifunction machine

Mains synchronisation using the dark circuit method Experiment procedure (dark method circuit):  

 





   

Operate the brake as a servo drive motor for the synchronous generator Put the brake into operation and use the control knob to set the synchronous speed of the three-phase multifunction machine Switch the exciter unit on If the lamps should light up alternately then one phase winding on the generator has to be exchanged Vary the rotation speed using the control knob so that all of the incandescent lamps are dark (out) At the right moment, i.e. when all of the incandescent lamps are dark - activate the S1 switch thus connecting the generator on line to the mains This concludes the synchronisation Observe the generator Subsequently disconnect the generator again from the mains Switch off the exciter unit and stop the servo brake

EEM5 Three-phase multifunction maschines Mains synchronisation (Three-phase multifunction machine) Mains synchronisation using the bright method circuit Experiment procedure (bright method): 

Modify the circuit connection in accordance with the following circuit diagram

1

2

3

L1

G2

1

2

L2

G3

L3

G1

3

Circuit diagram "Mains synchronisation (bright circuit)"

Experiment procedure (bright circuit cont'd):

EEM5 Three-phase multifunction maschines Mains synchronisation (Three-phase multifunction machine)  

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Put the brake back into operation (see "dark circuit") If the lamps are supposed to light up alternately, one of the phases on the generator must be exchanged Vary the speed using the control knob so that all of the incandescent lamps light up At the right moment, i.e. when all of the incandescent lamps light up the brightest activate the S1 switch thus connecting the generator on line to the mains This concludes the synchronisation Observe the generator Subsequently disconnect the generator again from the mains Switch off the exciter unit and stop the servo brake

EEM5 Three-phase multifunction maschines Mains synchronisation (Three-phase multifunction machine) Mains synchronisation using the three-lamp method Experiment procedure (three-lamp method): 

Alter the circuit connection in accordance accordance with the following following circuit diagram

"Mains synchronisation (three-lamp circuit)"

Experiment procedure (three-lamp method cont'd):

EEM5 Three-phase multifunction maschines Mains synchronisation (Three-phase multifunction machine)  

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Put the brake back into operation (see "dark method") Vary the speed using the speed control knob so that the lamp on the far left in the circuit is dak while the other two lamps light up At the right moment - when the lamp on the left is dark and the other two lamps lamps light up the brightest - activate switch S1 and thus switching the generator generator on line to the mains This completes synchronisation Observe the generator Afterwards disconnect disconnect the generator again from the mains Switch the exciter unit off and stop the servo brake

Which of the following statements are correct regarding the bright, dark and threelamp synchronisation methods? Dark circuit: All lamps are connected between different line conductors Bright circuit: Each of the lamps are connected on one side with a mains conductor and on the other side with a generator conductor that is phase-shifted by 120° Three-lamp synchronisation: Combined arrangement of the lamps, two lamps on one conductor and one lamp between the other two conductors, consequently only the one lamp lights up and the other two remain dark Dark circuit: Since the lamps are each connected into the same mains and generator conductor leads, the lamps do not light up at the right phase angle and sequence Bright circuit: The lamps are all connected in one phase conductor Three lamp circuit: Combination of bright and dark circuit. Two lamps are each connected with their phase phaseshifted with respect to the mains m ains and generator phases by120° (=> bright circuit). The third lamp is is again between identical identical mains and generator generator phases (=> dark circuit)

correct!


What do you need to watch out for with the bright circuit? With the bright method the rotary field of the synchronous generator plays no role at all in the synchronisation In the bright method synchronisation does not necessarily have to be the case for the incandescent lamps to be shining the brightest

correct!

When should two external conductors of the synchronous generator be exchanged? This measure is only required if the power mains, to which the generator is to be synchronised, has the correct clockwise rotational field In the case of the t he bright method, this is only supposed to be carried out if the incandescent lamps are not lighting up in cyclical sequence As soon as the incandescent incandescent lamps light up in cyclical sequence (bright or dark ) the interchanging of the external conductors is no longer absolutely necessary

correct!

What happens if the generator is connected asynchronously asynchronously on line to the mains? m ains? Due to the fact that a motor circuit-breaker is integrated into the circuit, nothing can happen If the generator should be switched asynchronously to the mains, very high short-circuit type currents arise which could endanger both man and machinery.

correct!

Mains synchronisation using double frequency meter, double voltmeter and synchronoscope Experiment procedure:

EEM5 Three-phase multifunction maschines Mains synchronisation (Three-phase multifunction machine) 

Modify the circuit connection in accordance with the following circuit and assembly diagrams

"Mains synchronisation" circuit diagram (Double frequency meter, double voltmeter and synchronoscope)


"Mains synchronisation" assembly diagram (Double frequency meter, double voltmeter and synchronoscope)

EEM5 Three-phase multifunction maschines Mains synchronisation (Three-phase multifunction machine) Experiment procedure (cont'd):  

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Operate the brake as a servo drive meter for the synchronous generator Put the brake into operation and use the control knob to set the synchronous speed of the synchronous generator Switch the exciter unit on Vary the speed using the control know until : the double frequency meter and double voltmeter indicate the same measured values for both circuits and the synchronoscope comes to a standstill at the mark shown above As soon as these conditions are fulfilled activate switch S1 and thereby switching the generator on line to the mains This concludes synchronisation Observe the generator Then disconnect the generator from the mains again Switch the exciter unit off and stop the servo brake 

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EEM5 Three-phase multifunction maschines Mains synchronisation (Three-phase multifunction machine) Mains synchronisation using double frequency meter, double voltmeter and zero voltage meter Experiment procedure: 

Modify the circuit as specified in the following circuit and assembly diagram

"Mains synchronisation" circuit diagram (Double frequency meter, double voltmeter and zero voltage meter)


"Mains synchronisation" assembly diagram (Double frequency meter, double voltmeter and zero voltage meter)

Experiment procedure (cont'd): 

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Put the brake back into operation (see "mains synchronisation using double frequency meter, double voltmeter and synchronoscope") Vary the speed using the control knob until: the double frequency meter and the double voltmeter indicate the same measured values for both circuits and the zero voltage meter displays 0 V As soon as these conditions are fulfilled, activate the S1 switch and thereby connecting the generator on line to the mains This concludes synchronisation 

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Training content: "Power feed (Classic Line)"  

Generation of capacitive and inductive reactive power Measure the generator power at variable drive power

Assembly instructions: "Power feed (Classic Line)" 

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Assemble the circuits in accordance with the following circuit and assembly diagrams Also switch the brake on as this does not subject the machine to any load

More detailed information on the brake can be found on the corresponding online documentation


"Power feed (Classic Line)" circuit diagram (Double frequency meter, double voltmeter and zero voltage meter)


"Power feed (Classic Line)" assembly diagram (Double frequency meter, double voltmeter and zero voltage meter)

Generation of capacitive and inductive reactive power (on synchronised generator) 

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Set the generator to mains synchronisation with the aid of the previous chapter "Synchronisation to mains" By now activating the S1 switch the servo brake is set to "Torque Control" & "Synchronisation" mode Increase the drive torque using the control knob in accordance with the values given in the table Vary the exciter current step-by-step as specified in the table below Measure the generator's electrical power output P, the reactive power Q and the power factor cos φ Enter the measured values into the table


M=-0,4Nm Ierr./A 1.0 1.5 2.0 2.5 3.0 3.5 4.0

P/W

Q/W

cos φ

Which of the following statements are true of the synchronous generator's excitation with respect to the values measured? In the case of underexcitation the generator feeds capacitive reactive power into the power mains In the case of underexcitation the generator feeds inductive reactive power into the power mains In the case of overexcitation the generator absorbs capacitive reactive power from the power mains In the case of overexcitation the generator feeds inductive reactive power into the mains

correct!


Measure the generator power at variable drive power (on the synchronised generator)  

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Set the exciter unit to a constant excitation level (see the table below) Vary the drive torque step-by-step using the control knob, in accordance with the values in the table In the process measure the generator's electrical power output P phase (Pph.) and Pexcitation (Pexc.) Based on the rotation speed and the torque compute the mechanical power Pmech consumed, whterby M corresponds to the torque and ωN corresponds to the nominal angular frequency. 

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Based on the variables determined compute the efficiency η of the synchronous generator Here please take also into account the power P excitation consumed for the excitation of the rotor Finally after successfully completing the measurments disconnect the generator from the mains Switch the exciter unit off and stop the servo brake


Ierr.=4A M/Nm -0.5 -1.0 -1.5 -2.0 -2.5

Pstr./W

3*Pstr.= P2/W

Perr.+Pmech= P2/P1*100= Perr./W Pmech./W P1/W η/%


How does the speed of the generator respond when the drive power is increased? The speed drops slightly The generator is coupled to the power mains by frequency and voltage The speed is increased slightly

correct!

Which of the following statements are true of the synchronous generator? If you would like to attain compensation by the generator in a mains power system under inductive or capacitive load, then this can be achieved through targeted underexcitation or overexcitation The generator's active power is only affected by its excitation The reactive power of a generator can only be changed by varying the synchronous speed A change in the reactive power has no practical significance whatsoever An increase in active power is only possible by increasing the mechanical drive power

correct!


EEM 5 Three-phase Multifunction Machines (English)

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