Capacitor motor, 1.0

The experiments are carried out with industrially manufactured machines class 1 kW. The 1 kW machines have a higher efficiency because of the lower winding resistance and come closer to an ideal machine. All test machines have a special base for connection to the machine testing system 1.0. The machine testing system is used to record the characteristic curves of the test machines. The machines are supplied via a variable transformer or the mains.

Objectives

• Protective measures and electrical safety
• Setting up AC machines and putting them into operation
• Use of starting circuits
• Assessment of AC machine characteristics

Capacitor motors are rotating field machines with squirrel cage rotors which operate on single-phase AC. The rotating field is elliptical and is generated by a 2-core stator winding. The main winding of the stator is connected directly to the power supply, while the auxiliary winding, which is displaced with respect to the main winding, is supplied via a capacitor connected in series. In order to increase the starting torque, a starting capacitor is connected in parallel with the operational capacitor via a relay.

Highlights:

• In order to protect against overheating, the stator windings of the test machines are equipped with temperature detectors.
• In case of overheating, the machine testing system switches off the load of the test machine, thus a preserved air cooling. This prevents damage to the testing machines.
• The test machines are equipped with an educationally designed terminal board with the winding configuration printed on it.
• The ends of all the windings are led out at the terminal board at safety sockets (4 mm).
• Computer-supported acquisition of measurement data provides for meaningful measurement results.
• The arrangement of the 4 mm safety sockets corresponds to the standards for industrial machines.

All functions of the Machine Test CASSY 1.0 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 Machine Test CASSY 1.0 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 Machine Test CASSY 1.0 for the local media connection of at least four end devices simultaneously.

For more details, see product data 7732900 or 7731901 Machine Test CASSY 1.0

The individual equipment is equally suitable for student experiments in the laboratory with low voltage (230 / 400 V three-phase current) and - with a mobile trainer - for teacher demonstration in the classroom. 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 AC machines:

• E2.3.3.1 Universal motor AC

Topics

• Connection of a capacitor motor with operational and starting capacitor plus current relay
• Reversing direction of rotation
• Measurement of efficiency and comparison with ratings on the rating plate
• Recording of load characteristics
• Investigating the effect of a starting capacitor
• Switching point for the starting capacitor
• Load characteristics