DESCRIPTION

Technical Description

With this experimental unit the operation of the pressure switches, also calledpressostats, used in refrigeration can be demonstrated. 

Pressure switches are used to protect the compressor and system components against too high or too low pressures. They are also used in the so-called pump-down circuits for the controlled shut-down of the compressor. Dependent on the application, individual pressure switches or combined pressure switches are used for high and low pressures.

Pressure switches for monitoring the pressures are available. The switching states are indicated by signal lamps. The switching thresholds and hystereses can be set by the trainee. This allows him to examine and understand the switching behaviour of the pressure switch. A typical refrigerant compressor generates the test pressures. Manometers indicate the pressures. Air is used as a pressure medium. The hazard-free operation of the pressure switches uses 24V.

The well-structured instructional material sets out the fundamentals and provides a step-by-step guide through the exercises.

Learning Objectives / Experiments

- gain expert knowledge of refrigeration through practical exercises
- operation of a pressure switch 
- difference between low and high pressure switches
- difference between NC and NO contacts of a switch
- setting the switching threshold
- setting the differential gap
- recording the switching behaviour of the pressure switch over pressure