The experiments are carried out using machines of industrial manufacture. All the test machines are equipped with a special base for attachment to the Machine test system 0.3. The system allows the characteristics of the machines under test to be recorded. Power for the machines under test is provided via a variable transformer.

Objectives

• Protective measures and electrical safety
• Setting up electrical machines and putting them into operation
• Use of starting circuits
• Assessment of electrical 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 two-phase 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.

Features

• In order to protect against overheating, the stator windings of the test machines are equipped with temperature sensors
• Should overheating occur, the machine testing system automatically shuts down the machine under test, thus preventing any damage to it.
• 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 connected to the terminal board and can be accessed via 4-mm safety sockets.
• Computer-supported acquisition of measurement data provides for meaningful measurement results.

The complete equipment set is equally suitable for student experiments in laboratories with low voltage supplies (230 V AC) and for setting up on a mobile trolley for demonstration by teachers in a classroom. The procedures for the experiments are provided in a printed 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.

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
• Load characteristics

Similar to illustration