The coasting period is from T3 to T4 i.e, from C to D. At the instant, the power supply to the motor will be cut off and the speed falls on account of friction, windage resistance, etc. During this period, the train runs due to the momentum attained at that particular instant. The rate of the decrease of the speed during the coasting period is known as coasting retardation.
Form factor: The ratio of r.m.s (or effective) value to average value is the form factor (Kf) of the Waveform. It has used in voltage generation and instrument correction factors.
Peak factor: The ratio of maximum value to the r.m.s value is the peak factor (Kp) of the waveform.
Form Factor × Peak Factor = (RMS Value / Average Value) * (Maximum Value / RMS Value) = Maximum Value / Average Value
To find the Thevenin’s resistance the current source is open-circuited and the voltage source is short-circuited.
Air friction Damping: An air friction damping device is usually provided with moving iron instruments such as voltmeters and ammeters.
In this device, a light aluminum vane is attached to a spindle as shown in Fig.
and this vane is free to move in a fixed air chamber known as a sector. When the pointer deflects, the vane in the sector also moves. The air in the sector produces friction in the movement of the vane and thus necessary damping torque is obtained.
Eddy Current Damping: It is used in a strong operating field e.g., PMMC (Permanent Magnet Moving Coil instrument) type.
Fluid Friction Damping: Used in high voltage measurement. Used in the vertically mounted instrument. e.g., Electrostatic type instrument.
Indian Electricity Rules specify that the maximum load on a light/fan sub-circuit should not exceed 800 watts and the number of points should be limited to 10.
Hence for light load number of sub-circuit = 3000/800 = 3.75 = 4
Indian Electricity Rules specify that the maximum load on a power sub-circuit should not exceed 3000 watts and the number of outlets should be limited to two.
For the power sub-circuit load number of sub-circuit = 6000/3000 = 2
Total subcircuit = 4 + 2 = 6