EDUTEC   Educatie en Techniek

EPE/F Fault Finding - Phase Control Circuit

System Description

Phase control is used in the control of rectifiers for AC and three-phase voltages, e.g. in light dimmers. There are two distinct circuit groups, the load circuit and the bridge rectifier, which form part of the LN fault simulator. A filament lamp is used as a load and a potentiometer is to vary the phase angle between 10 and 160°. The circuit is operated with real voltages (250V) and the following 17 faults can be simulated :

1. Diode defect
2. transformer secondary winding defect
3. Thyristor faults
4. Unijunction transistor faults
5. Restricted range of adjustment due to small capacitance
6. Zener diode defect
7. Defect fuse
8. Broken cable to lamp
9. Defect resistors
10. Potentiometer slider contact defect
11. Short circuit in capacitor

Topics Covered