What is the difference between isolating and shielding transformer? No-load losses and Load Losses. Lighting power protection devices- These are the devices that are used to protect the system from surge voltages or ... insulation failure of cables and winding leads to failure of equipment like generators, motor, transformer. It is big in size as compared to distribution transformer, it used in generating station and Transmission substation. Till that heat reaches the cooling medium removes the heat. In a transformer the energy is conveyed from primary to secondary (a) through cooling coil (b) through air (c) by the flux (d) none of the above Ans: c. 3. 4)      I2R losses due to no-load current in the primary and secondary windings. the output is high compared to input voltage but the power ratio is same. It is chemically stable and has high thermal conductivity and dielectric strength. Today we are sharing interview questions on transformer. Voltage transformer is sometimes called as potential transformer which is used to measure the voltage of the line. Transmission lines and generating stations, High (as the loads will be disconnected and connected), On-load tap changer to encounter the load fluctuations, Heat losses are high because of high rated current, Heat losses are low because of low rated currents, Transformers Interview Questions & Answers, Functions of Instrument Transformers (CTs and PTs), One set of primary and secondary windings. What important things need to be ensured in installing a 11000/433 volts, 500KVA distributing transformer indoors ? A tap changer is a device used to change the primary or secondary voltage of the transformer by changing the turn’s ratio without remodeling the transformer. ... Top 100 Switchgear and Protection Interview Questions. A transformer is a passive electrical device that is used to transfers Electrical Energy between two or more electrically isolated circuits. 1. What are the functions of protective relays. The 50 Hz transformer can be operated at 60Hz for some cases but 60 Hz transformer cannot be operated for 50Hz. To know the answer in detail, click on the link given in the answer. %impedance: It indicates the amount of voltage drop from the no-load current to full load current. The main difference between induction motor and transformer is that transformer is a static machine and motor is an rotating machine. • Internal Faults (the faults within the transformer): 11. Save my name, email, and website in this browser for the next time I comment. There is no isolation between primary and secondary. (a) Current (b) Voltage (c) Frequency (d) All of the above Ans: c. 2. Ans. Interview Questions on Transformer - Free download as Word Doc (.doc / .docx), PDF File (.pdf), Text File (.txt) or read online for free. We have planned to give you 100 Interview Questions on Power Transformer. Distance Protection is a Non-unit System of Protection, which... Two Main and One Transfer Bus System Explained. This flux reduces the main flux induced in the primary & also reduces E.M.F E 1 in the primary. What parameters or technical particulars are important to be considered while designing protection scheme of the transformer? The transformer cannot be operated more than 10% higher than the rated voltage because if the primary is high therefore secondary also increases which leads to increase in power rating of a transformer. 4. a) Dielectric breakdown voltage indicates the presence of electrically conductive contaminants in oil. (c) low … The impedance of the transformer is the combination of resistance and reactance of the primary and secondary winding coils. What is an equivalent circuit of a transformer? What is protective relay? The current transformers can be used for metering purpose or for protection purpose. 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