EK Technologies

ELCB AND RCCB (RCD) Earth Leakage Circuit Breaker (ELCB) Working Principle of ELCB An Earth Leakage Circuit Breaker (ELCB) is a security device used in an electrical installation to detect leakage current and protect humans against the risk of an electric shock, from this leakage current. The operation is such that, the power supply connected at its switching terminal (contact of the circuit breaker) is disconnected by a special type of latching relay when it detects a leakage current. Thereby, protecting individuals getting in contact with this leakage current against the risk of an electric shock. This circuit breaker remains OFF until reset manually. Types of Earth Leakage Circuit Breaker They are two types of Earth Leakage Circuit Breakers. They are named based on their principle of operation. They are; The Voltage Earth Leakage Device (Known as the ELCB) and The Current Earth Leakage Circuit Breaker (RCD or RCCB). In the past, when referring to Earth Lea

  GCE Advanced Level Past Questions   Technical and Vocational Education Examinations Electrical Power Systems EPS Power Electronics Specialty Name (Specialty Code) Electrical Power Systems EPS (F3) Subject Title   Power Electronics Paper Nº   2 Subject Code Nº 7235  1.  Control of a D.C motor          The circuit shown in figure 1, include the control and the power circuit of a DC motor to make the up and down movements of a system. All the OP-AMP and switches are ideal a)   Study of the control circuit (OA1; R’s and (AO2). i)       Give the operating mode of the operational amplifiers (OA1; R’s) and (AO2).                  ( 6 marks) ii)      prove that the expression of the voltage at the OA1  inverting input terminal in function of V 1  and V 01  is  V- = ( V 1  + V 01 ) / 2         (6 marks) iii) Prove that the expression of the voltage a