This trainer must have modular structure and it must consist of didactic panels that shall be installed on a vertical frame. 
The modularity of this didactic system must grant to the students a direct and  immediate approach to the topic, offering the opportunity to study various subjects performing different experiments:

• Transformer Vector Group
• No-Load Performances
• Short - Circuit Performances
• Load Performances
• Zero Impedance
• Asymmetrical Load
• Autotransformer

The minimum set of power engineering modules should include the following:
THREE-PHASE POWER SUPPLY - Didactic equipment: 
three-phase variable power supply, power supply unit for variable 3-phase voltage suitable for supplying ac machines. It must provide an AC output 3-phase from 0 to 380 V, 8 A minimum. 
It must be provided with a 16 A, 30 mA differential magneto-thermal main switch, a key operated emergency push-button, start and stop push-buttons, a motor protection circuit breaker: 6.3 to 10 A, a digital ammeter and a digital switchable voltmeter. 4 mm safety terminals for electrical connections included. 
The output voltage must be set by a rotary knob with 0-100% scale. 
Supply voltage:
three-phase from mains.
OVERHEAD LINE MODEL - Didactic equipment: 2 pcs
module with insulated panel, three-phase line model of an overhead power transmission line of 360 km long, voltage 380 kV and current 1000 A, scale factor: 1:1000. Line resistance: 13 Q, line inductance: 290 mH, mutual capacitance: 1 uF, earth capacitance: 2 (iF, earth resistance: 11 Q, earth inductance: 250 mH. 4 mm. safety terminal included on the front panel.
THREE-PHASE TRANSORMER - Didactic equipment: 
three-phase transformer for feeding a transmission line model, 380 kV with scale factor 1:1000. 
Primary: 3 x 380 V with tap at 220 V, star or delta connection. 
Secondary: 3 x 220 V windings with taps at +5%, -5%, -10%, -15%,star connection for 3 x 380 V, various star connections possible. 
Nominal power: 800 VA minimum. 
4 mm. safety terminal included on the front panel for the electrical connection.
RESISTIVE LOAD - didactic equipment
It must consist in a single or three-phase resistive step-variable load. Housed in a metallic box.
MECHANICAL FEATURES
The load shall be composed of a rugged metal structure and of a front metal panel.
On the front panel all the controls, the protection, the output terminals and a clear synoptic diagram, shall be collected.
ELECTRIC FEATURES
The load shall be composed of resistances, with possibility of star, delta and parallel connection, controlled by three
switches. This item must be provided also with fuses protection.
As a function of the switch positions, there shall be the following phase values:
Position    Resistance      Max power per phase
1    1050 Ohm           46 W
2    750 Ohm            65 W
3    435 Ohm           110 W
4    300 Ohm        160 W
5    213 Ohm        230 W
6    150 Ohm        330 W
7    123 Ohm        400 W
Maximum power in single or three phase connection must be 1200 W.
Rated voltage in star connection must be 380 V, in D connection must be 220V, in single-phase must be 220V. 4 mm. safety terminal included on the front panel for the electrical connection.
INDUCTIVE LOAD - didactic equipment
It must consist of a single or three-phase inductive step-variable load. Housed in a metallic box.
MECHANICAL FEATURES
The load shall be composed of a rugged metal structure and of a front panel.
On the front panel all the controls, the protections, the output terminals and a clear synoptic diagram, shall be collected.
ELECTRICAL FEATURES
The load shall be composed of inductances, with possibility of star, delta and parallel connection, controlled by three switches.
This item must be provided also with fuses protection.
As a function of the switch position there shall be the following phase values.
Position    Inductance   Max. Power per phase
1    4.46 H           34 VAr
2    3.19 H            48 VAr
3    1.84 H            83 VAr
4    1.27 H            121 VAr
5    0.90 H            171 VAr
6    0.64 H            242 VAr
7    0.52 H            297 VAr
Max reactive power 890 VAr in three-phase or single-phase connection.
Rated voltage in star connection must be 380V, in D connection must be 220V, in single-phase must be 220V. 4 mm. safety terminal included on the front panel for the electrical connection.
CAPACITIVE LOAD - didactic equipment
It must consist of a single or three-phase capacitive step-variable load. Housed in a metallic box.
MECHANICAL FEATURES
The load shall be composed of a rugged metal structure and on the front panel all the controls, the protections, the output terminals and a clear synoptic diagram shall be collected. This item must be provided also with fuses protection.
ELECTRICAL FEATURES
The load shall be composed of capacitors, with possibility of star, delta and parallel connection, controlled by three switches.
As a function of the switch position, there shall be the following phase values (at 50Hz):
Position   Capacitance      Max power per phase
1    2 uF                   30 VAR
2    3 uF                    45 VAR
3    5 uF                    76 VAR
4    8 uF                    121 VAR
5    10 uF                 152 VAR
6    13 uF                 197 VAR
7    18 uF                 275 VAR
Max reactive power in single-phase or three-phase connection 825 VAr.
Rated voltage in star connection must be 380V, in D connection must be 220V, in single-phase must be 220V. 4 mm. safety terminal included on the front panel for the electrical connection.
THREE-PHASE SUPPLY UNIT

• - Didactic equipment: 
• Power supply unit for three-phase  connection with 4-pole cam mains switch. 
• 25 A current operated earth leakage circuit breaker, sensitivity 30 mA.
• Triple-pole motor protection switch: 6.3 to 10 A.
• Three-phase indicator lamps.
• Output through 5 safety terminals: 
• L1, L2, L3, N and PE.
• Switch for simulation of wind or  photovoltaic energy power source
• 4 mm. safety terminal included on the front panel for the electrical connection.
• POWER CIRCUIT BREAKER
  1. - Didactic equipment:  4 pcs 
  2. Three-phase power circuit breaker with normally closed auxiliary contact.

1. Features:
2. Contact load capability: 400 Vac, 3 A
3. Supply voltage: single-phase from mains
4. Power circuit:
5. Insulation voltage: 750V
6. Thermal current : 20A
7. Auxiliary contact:
8. Insulation voltage: 750V.
9. Rated current: 3A
10. Auxiliary power:
11. Single-phase voltage 220V, 50-60Hz
12. It must be possible to control manually the power breaker switch using the push-buttons “on”and “off” or externally via the switching contact PLC or RELAY.
13. This power contacts state shall be indicated by leds:
14. Green led = open contacts.
15. Red led = closed contacts.
16. While at SIGNAL OUTPUT terminals will be  available a TTL level:
17. Low level ( 0V )= open contacts.
18. High level ( 5V )= closed contacts.
19. The RS flip-flop state shall be indicated by a led:
20. Yellow led = set flip-flop.
21. 4 mm. safety terminal and 2 mm. terminals included on the front panel for the electrical connection.
22. It must be supplied with manual in English language
23. DOUBLE BUSBAR WITH TWO DISCONNECTORS - Didactic equipment:                                   
    1. module with insulated panel
    2. Suitable for extending the double busbar system.
    3. The module must have insulated front panel and four light push buttons (two red and two green).
    4. Each busbar must have a supply branch that will be connected or disconnected by using a disconnector. 
    5. It must be possible to control manually the power breaker switch using two couples of  push-buttons “on”and “off” or externally via the switching contact PLC or RELAY.
    6. This power contacts state shall be indicated by leds:
    7. Green led = open contacts.
    8. Red led = closed contacts.
    9. While at SIGNAL OUTPUT terminals will be  available a TTL level:
    10. Low level ( 0V )= open contacts.
    11. High level ( 5V )= closed contacts.
    12. The RS flip-flop state shall be indicated by a led:
    13. Yellow led = set flip-flop.
    14. 4 mm. safety terminal and 2 mm. terminals included on the front panel for the electrical connection.
    15. It must be supplied with manual in English language
24. DOUBLE BUSBAR WITH FOUR DISCONNECTORS Didactic equipment: 
    1. module with insulated panel 
    2. Suitable for extending the double busbar system.
    3. The module must have insulated front panel and eight light push buttons (four red and four green).
    4. Each busbar must have a supply branch that will be connected or disconnected by using a disconnector. 
    5. It must be possible to control manually the power breaker switch using four  couples of  push-buttons “on”and “off” or externally via the switching contact PLC or RELAY.
    6. This power contacts state shall be indicated by leds:
    7. Green led = open contacts.
    8. Red led = closed contacts.
    9. While at SIGNAL OUTPUT terminals will be  available a TTL level:
    10. Low level ( 0V )= open contacts.
    11. High level ( 5V )= closed contacts.
    12. The RS flip-flop state shall be indicated by a led:
    13. Yellow led = set flip-flop.
    14. 4 mm. safety terminal and 2 mm. terminals included on the front panel for the electrical connection.
    15. It must be supplied with manual in English language
25. LINE CAPACITOR
    1. Didactic equipment: 2 pcs
    2. module with insulated panel, three-phase transmission line capacitor with exactly half of the operating capacitance of the 380 kV transmission line model with a length of 360 km, Capacitance:3 x 2.5 uF, 450 Vac. 4 mm. safety terminal included on the front panel for the electrical connection.
26. PETERSEN COIL
    1. - Didactic equipment: 
    2. module with insulated panel, Petersen coil, inductance with 20 taps for earth fault compensation in transmission lines: 2000mH-1800mH-1600mH-1400mH-1250mH-1100mH-980mH-860mH-750mH-620mH-500mH-400mH-300mH-220mH-160mH-120mH-80mH-40mH-20mH-5mH-0.
    3. Inductance: 0.005 ... 2 H
    4. Rated voltage: 220 V
    5. Rated current: 0.5 A
    6. 4 mm. safety terminal included on the front panel for the electrical connection.
27. MOVING COIL AMMETER MODULE
    1. didactic equipment  
    2. The module must consist of a magneto-electric meter for ac and dc measurements.
    3. Scale: 50 divisions - the scale shall made open and reasonably uniform down to about 20 percent of the full-scale reading.
    4. Range: 100, 500 and 1000 mA, ac/dc
    5. Accuracy class: 1.5
    6. This module must have insulated front panel , 4 mm safety terminals, one selector and one analog meter.
    7. The module must be supplied with manual in English language.
28. MOVING COIL AMMETER MODULE
    1. didactic equipment  3 pcs 
    2. This module must be suitable for ac and dc current measurements.

Technical features:

• Scale: 50 divisions - the scale shall made open and reasonably uniform down to about 20 percent of the full-scale reading.
• Range: 2.5 A - 1.25 A
• Accuracy class: 1.5
• AC/DC measurements
• This module must have insulated front panel, 4 mm. safety terminals, one selector and one analog meter.
• The module must be supplied with manual in English language.
  1. MOVING IRON VOLTMETER MODULE
     • - didactic equipment       2 pcs 
     • This module must be suitable for ac and dc voltage measurements.

Technical features:

1. Scale: 30 divisions - the scale shall be made open and reasonably uniform down to about 20% of the full-scale reading.
2. Range: 600 V
3. Accuracy class: 1.5
4. This module must have insulated front panel with the electrical scheme, 4 mm safety terminals, fuse protection and one analog meter.
5. The module must be supplied with manual in English language.
6. MOVING IRON VOLTMETER MODULE - didactic equipment      3 pcs                                         
7. This module must be suitable for ac and dc voltage measurements.

Technical features:

1. Scale: 50 divisions - the scale shall be made open and reasonably uniform down to about 20% of the full-scale reading.
2. Range: 125-250-500 V
3. Range changeover switch
4. Accuracy class: 1.5
5. This module must have insulated front panel with the electrical scheme, 4 mm safety terminals, fuse protection and one analog meter. One selector shall be included in this panel.
6. The module must be supplied with manual in English language.
   1. POWER METER -
      1. Didactic equipment :   2 pcs 
      2. This module must consist in a demonstration single-phase meter for active power and capacitive/inductive reactive power.

Technical features: 

1. Measurement ranges: Voltage: 3/10/30/100/300/1000 V
2. Current: 0.1/0.3/1/3/10/30 A 
3. Frequency range: Active power: 0 ... 20 kHz
4. Reactive power: 50 Hz 
5. LED indicators: capacitive reactive power, inductive reactive power, overload voltage (with acoustic sound), overload current (with acoustic sound).
6. Auxiliary supply: single-phase from mains
7. This module must have insulated type front panel with the electrical scheme and also 4 mm safety terminals. Two selectors, one switch and one push-button shall be included in this panel.
   1. POWER FACTOR METER -
   2. Didactic equipment:  The module must consist of  one single-phase power factor meter with measurement of the power factor and phase-angle with ranges: power factor: 0 cap to 1 to 0 ind, phase-angle: -90°cap to 0 ... +90°ind.
   3. Measurement ranges: 
   4. voltage 3 / 10 / 30 / 100 / 300 / 1000V
   5. Current 0.1 / 0.3 / 1 / 3 / 10 / 30A
8. Frequency range: 
9. active power 0…20 kHz
10. reactive power 50Hz
11. Led indicators: 
12. capacitive reactive power
13. inductive reactive power
14. overload voltage, with acoustic sound
15. overload current, with acoustic sound
16. Auxiliary supply: 220V, 50-60Hz
17. 4 mm safety terminals for electrical connections included 
18. It  must be supplied with manual in English language.
    1. WORKBENCH 
       1. This item must consist in a large sized bilaminated wooden board and square legs with compensation feet.
       2. Dimensions: 2 x 0,8 x 0,9 m
       3. A set of cables with at least 80 connecting leads with security plugs of different colours, length and sections.
    2. THREE-LEVEL FRAME 2 pcs
       Metal frame with three levels for fitting the modules of the laboratory.
       Set 7