Drives with educational frequency converter

The importance of frequency converters for manufacturing and operating concepts has never been greater. A frequency converter optimises not only the motor operation, but often the entire driven machine. Frequency converters are used with the following objectives:

• Optimisation of energy efficiency,
• Efficient factory automation,
• Process control and optimisation.

This configuration deals with the optimal adaptation of frequency converters and machines without controlling the speed.

Highlights:

• The measurements are carried out with the Converter Controller CASSY.
• All measuring channels are potential-free and can therefore be used freely.
• All measurements can be carried out with or without a computer.
• To protect against overheating, the stator windings of the asynchronous motor are equipped with temperature detectors.
• The asynchronous motor has a didactic terminal board with the winding diagram printed on it.

All functions of the Converter Controller CASSY and the Machine Test CASSY 0.3 can be operated quickly and directly via the display, the rotary wheel and the buttons on the unit. All settings and measurement results can be saved on the unit and quickly called up again later or simply downloaded.

In addition, the Converter Controller CASSY and the Machine Test CASSY 0.3 is fully controllable in real time via RJ45 Ethernet, W-LAN and USB-C interfaces.

These interfaces can be used by the following software:

• CASSY Lab 2 for drives and energy systems,
• MATLAB® and LabVIEW ™
• Lab Docs Editor Advanced

Several integrated servers are available in Converter Controller CASSY and the Machine Test CASSY 0.3 for the local media connection of at least four end devices simultaneously.

For more details, see product data 7735290 or 7735291 Converter Controller CASSY and the 7731900 or 7731901 Machine Test CASSY 0.3.

The equipment is equally suitable for pupil and student experiments in the laboratory with low voltage (DC, AC and three-phase current) and - with a mobile trainer - for teacher demonstrations in the classroom or lecture hall. The experiments are carried out according to the manual.

The target group is made up of commercial apprentices and students of electrical machine construction. The course offers experiments at an intermediate level and also allows for the necessary insight into machine behaviour for scientific interpretation at undergraduate level. The media connection makes the experiments suitable for demonstration in the classroom or a lecture hall.

In the following configurations there are further extended experiments with a frequency converter and an asynchronous machine:

• E2.5.3.2 Basics of frequency converter technology
• E2.5.3.4 Drives with industrial frequency converter
• E2.5.4.4 Operating behaviour of speed-variable asynchronous motors under load
• E2.6.2.2 AC servo with industrial asynchronous machine

Topics

• Rotating field and space vector
• Modulation frequency
• Modulation types: rectangle, trapezoid, sine, sine with 3rd harmonic oscillation.
• Magnetisation with linear V/f characteristic curve
• Enhancement of magnetisation by start voltage
• Starting with boost
• Optimisation of load characteristics through IxR compensation
• Slip compensation
• Load compensation
• Recording the effect of load and slip compensation in the load characteristic curve
• Recording of operating curves for several frequencies and directions of rotation
• Comparison of several load curves
• Generator operation and braking