Why Generator Armature Winding Connected in STAR not in DELTA?

Alternator or generator armature winding is always connected in STAR not in DELTA. We know that rotating magnetic filed in the air gap can only be created if the phase winding and phase currents are 120º displaced from each other in the space and time respectively. This can be achieved either in star connection or delta … Read more Why Generator Armature Winding Connected in STAR not in DELTA?

Generator V-Curve and Power Factor Control

V-curve and power factor control of generator are closely related to each other. V-curve of Generator is basically a plot of variation of armature current with the change in field current. For a constant power, V-curve can only be obtained for  generator connected to infinite bus / grid. There does not exists any such curve for an isolated … Read more Generator V-Curve and Power Factor Control

End Part Heating in Generator

End Part Heating is localized heating at the end region of stator core of Generator. This heating is a result of eddy current loss in the laminations of stator core due to end turn flux of armature winding. This heating imposes a limitation on the operation of Synchronous Generator know as End Part Heating Limit. … Read more End Part Heating in Generator

Principle of Automatic Voltage Regulator

Automatic Voltage Regulator (AVR):  Automatic Voltage Regulator is a device which maintains the Generator output terminal voltage. To be more accurate, AVR is a controller which always compares the Generator output terminal voltage Vt with the set reference voltage Vrefand as per the error signal i.e. (Vref – Vt) it changes the filed excitation of … Read more Principle of Automatic Voltage Regulator

Rating of Synchronous Generator or Alternator

The rating of AC Machines such as Transformer, Alternators etc. are determined by the heating and hence losses in them. These losses are made up of Ohmic (I2R loss ) and Core Loss and a small amount of friction & windage loss. The ohmic loss depends upon the current and the core loss depends upon … Read more Rating of Synchronous Generator or Alternator

Open Circuit and Short Circuit Characteristics of Synchronous Machine

Open Circuit Test and Short Circuit Test are performed on a Synchronous Machine to find out the parameters of Synchronous Machine and hence to have an idea of their performance.  Open Circuit Test of Synchronous Machine is also called No Load, Saturation or Magnetizing Characteristics for the reason which will be clear after going through … Read more Open Circuit and Short Circuit Characteristics of Synchronous Machine

Why Hydrogen used for the Rotor Cooling of Generator

Hydrogen is used for the cooling of Rotor winding i.e. field winding and Rotor Core in Turbo Generator. As shown in figure below, there are small windows on the Rotor structure which allows the passage of Hydrogen. This hydrogen cools the Rotor structure and filed winding. This hydrogen after cooling becomes hot which in turn … Read more Why Hydrogen used for the Rotor Cooling of Generator