DC Distribution System: It is a common knowledge that electric power is almost exclusively generated, transmitted and distributed as a.c. However, for certain applications, d.c. supply is absolutely necessary. For…
Thermal Resistance to Heat Flow: The Thermal Resistance to Heat Flow between two points in a medium (e.g. insulation) is equal to temperature difference between these points divided by the…
Three Phase Service Cable: In practice, underground cables are generally required to deliver 3-phase power. For the purpose, either three-core cable or three single core cables may be used. For…
Underground Cables: Electric power can be transmitted or distributed either by overhead system or by underground cables. The underground cables have several advantages such as less liable to damage through storms…
Low Power Factor: The Low Power Factor plays an importance role in ac. circuits since power consumed depends upon this factor. It is clear from above that for fixed power…
Machine Tools Motors Requirements: The Machine Tools Motors Requirements are: The motors must be reliable and low cost, requiring less maintenance. They must be capable of speed control. Some applications…
Periodic Intermittent Duty: The class of duty making use of the ability of electric motors to operate with overload is called Periodic Intermittent Duty. The load on the motor is…
Short Time Intermittent Duty: Another class of duty for normally occurring loads is Short Time Intermittent Duty in which the load requires a constant power for a short interval of…