Teaching System Power Electronics
Four-quadrant Drive

Isolation amplifier

The isolation amplifier was developed for potential-free and safe measurement of different voltages in connection with an oscilloscope.

• 4 potential-free differential inputs
• Each input switchable to GND/DC/AC
• Switchable NF filter
• All measurement outputs via fully insulated BNC sockets
• Overload display for all channels

Brake unit

The DC braking unit is intended for use in drive technology, e.g. for experiments with a three-phase asynchronous motor and a frequency converter. It can be used as a motor and also as a generator.

4-channel isolation amplifier

The isolation amplifier was developed for potential-free and safe measurement of different voltages in connection with an oscilloscope.

• 4 potential-free differential inputs
• Each input switchable to GND/DC/AC
• Switchable NF filter
• All measurement outputs via fully insulated BNC sockets
• Overload display for all channels
• Can be used directly as a desktop unit or in a demonstration rack

Universal power supply

The universal power supply provides all the voltages required to carry out the experiments.

Four-quadrant drive

With the four-quadrant drive, we offer you a teaching and learning device for carrying out experiments in the field of speed control and speed regulation of DC shunt-wound machines.

• Compact design, thus short set-up times
• For DC machines from 100 W ... 1 kW
• Circuit-current and circuit-current-free operation, switchable
• Built-in controllers for current and speed
• Optical display of the switching status of the thyristors
• Measuring sockets for recording electrical parameters

Measuring and adjustment facilities are provided for recording and displaying all important electrical parameters. The four-quadrant drive is designed in such a way that it can be used to operate DC machines with an output of up to 1 kW.

To carry out experiments, the training board is placed on the table or hung in an A4 experiment rack for demonstration.

• Electronics technician for operating technology
• Electronics technician for automation technology
• Electronics technician for building and infrastructure systems
• Electronics technician for energy and building services engineering
• Mechatronics technician

General description:

• Power unit
• Operating modes of the four-quadrant drive
• The ignition modules Z1 and Z2
• The blocking logic (circular current logic)
• Speed controller
• The current regulators 1 and 2
• The enable signal
• Field voltage generation

The direct current shunt machine:

• Valve types (short version of the most important types)
• Semiconductor diode
• Thyristor (controllable on the cathode side, reverse-break)
• Thyristor can be switched off (GTO), controllable on the cathode side
• Triac, bidirectional thyristor
• Power converter, definitions

Two-pulse bridge circuits B2:

• B2 circuit with resistive load/diodes
• B2 circuit with R and L (ωL>>R)/diodes
• Fully controlled B2 circuit with resistive load/thyristors
• Fully controlled B2 circuit with R and L (ωL>>R).

Principle of a speed control:

• Basic principle of a closed-loop control
• The P-controller
• The I-controller
• The PI controller
• Block diagram (principle circuit diagram) of a speed control of a direct current machine
• The control set (ignition modules)
• Signal flow diagram of the speed control circuit
• Block diagram (schematic circuit diagram) of the four-quadrant drive (art. no. 54514)

Experiment section:

• General instructions
• Commissioning instructions

Experiments:

• Determining the field voltage UE of the four-quadrant drive Measurements on the speed controller
• Measurements on the current regulators
• Ignition pulses
• Characteristic curve of the tachogenerator
• Ohmic load of the thyristor bridges
• Maximum speeds in motor operation with different controller settings
• Voltage curve of the armature voltage UA1, A2 of the DC shunt motor at regenerative load
• Dynamic control behaviour of the speed controller in the case of abrupt application of speed changes and disturbance variables

Generator operation of the DC shunt machine M1 (directly connected to the thyristor), inverter operation, transition behaviour

Isolating amplifier

• Mains connection:
• Mains voltage: 230 V AC (standard version)
• Mains frequency: 50 ... 60 Hz
• Power consumption: approx. 20 VA
• Please specify special voltage of 110 V when ordering, as retrofitting can only be carried out at the factory.
• Dimensions (W x H x D): 266 x 297 x 110 mm
• Weight: approx. 2.4 kg

Brake unit

• DC shunt-wound machine:
• Armature voltage and current: 205 V / 2 A
• Field voltage and current: 205 V / 0.33 A
• Power: 0.3 kW, at 2000 rpm
• Protection by thermal contact
• Dimensions (W x H x D): 710 x 220 x 250 mm
• Weight: approx. 13.7 kg

Universal power supply

• Mains connection:
• 220 V ... 240 V AC / 380 V ... 415 V AC, 3-phase Output voltage and current (3-phase):
• 220 V ... 240 V AC / 380 V ... 415 V AC (6 A); with phase control lamp and circuit breaker, 3-pole (6 A).
• Dimensions (W x H x D): 266 x 297 x 195 mm
• Weight: approx. 8.6 kg

Four-quadrant drive

• Mains connection (single-phase):
• Mains voltage: 230 V AC; 50 ... 60 Hz
• Dimensions (W x H x D): 266 x 297 x 190 mm
• Weight: approx. 14.9 kg

DC shunt-wound machine

• Data nameplate:
• Power: 0.37 kW
• Speed: 1500 rpm
• Star connection: 400 V / 0.85 A
• Delta connection: 230 V / 1.47 A
• Dimensions (W x H x D): 290 x 160 x 215 mm
• Weight: approx. 7.5 kg

Mechanical specifications

The front panel of the training boards is made of 5 mm thick laminate, colour matt blue, and is engraved with white switching symbols corresponding to the built-in function groups. A sturdy plastic cover protects the rear of the unit and, thanks to its shape, allows the unit to be placed at an angle on the table to suit the work.

• Universal power supply from teaching system - Electrical machines
• DC brake unit
• 4-channel isolation amplifier
• Load with switch
• Four-quadrant drive
• Wiring harness for four-quadrant drive
• DC shunt machine