Knowledge is power essay

  This set of Electrical Measurements & Measuring Instruments Multiple Choice Questions & Answers (MCQs) focuses on “Ratios of Instrument Transformers”. 1. Transformation ratio of an instrument is defined as a) ratio of primary to secondary phasor b) ratio of secondary to primary phasor c) reciprocal of the primary phasor d) reciprocal of the secondary phasor View Answer Answer: a Explanation: For an instrument transformer, the transformation ratio is defined as the ratio of the magnitude of the actual primary phasor to the magnitude of the secondary phasor. 2. For a C.T. the transformation ratio is given by the relation a) R =  I s  ⁄  I p b) R =  I p  ⁄  I s c) R =  1  ⁄  I p d) R = I p View Answer Answer: b Explanation: In a current transformer, the transformation ratio is given by the ratio of the magnitude of the actual primary current to the magnitude of the actual secondary current. R =  I p  ⁄  I s where, R...

  The electrical instruments are not directly connected to the meters or control apparatus of high voltage for safety purpose. The instrument transformers like voltage transformer and current transformer are used for connecting the electrical instruments to the measuring instruments.These transformers reduce the voltage and current from high value to the low value which can be measured by conventional instruments. The construction of the current and potential transformer is similar as both have the magnetic circuit in their primary and secondary winding. But they are different in the method of working. There are several types of differences between the voltage and the current transformer. One of the major difference between them is that the current transformer converts the high value of current into low value whereas the potential or voltage transformer converts the high value of voltages into low voltage. Some other differences between the current and the potential transformer are...