Voltage Regulation Of Synchronous Machines [Alternator] By Direct Loading Test
Today in this post we are going to learn what is Voltage regulation of synchronous machine and different methods to calculate Voltage regulation of synchronous machine.
The definition of Voltage regulation of a synchronous machine:
Voltage Regulation of synchronous machine is defined as the difference between the terminal voltage at no load and terminal voltage at full load and excitation, speed must remain same.Voltage Regulation of synchronous machine is generally calculated in percentage of full load terminal voltage.
Objectives for calculating Voltage regulation of a synchronous machine:
1. Parallel operation of alternators is affected by the voltage regulation. By calculating voltage regulation of synchronous machine we can adjust the parallel operating machines to be in synchronism.
2. Calculating voltage regulation of a synchronous machine determines the type of automatic voltage control equipment required for resisting the voltage changes.
3.When the load is thrown off voltage rise must be known because with the rise in voltage the insulation must be able to withstand this rise.
So the calculation of voltage regulation of synchronous machine has a great importance.
The general expression for calculating Voltage regulation of synchronous machine:
Now let us derive the general expression for calculating voltage regulation of a synchronous machine
Let E be the terminal voltage of the synchronous machine at no load. Now if the synchronous machine is given full load the terminal voltage will no longer be E because of the losses so let the terminal voltage now be V.
So general expression for Voltage regulation of a synchronous machine is given by
Voltage regulation% = (E – V / V) × 100
Methods for calculating voltage regulation of synchronous machine:
There are two types of methods for calculating voltage regulation of synchronous machine.
1. Direct load test method.
2. Indirect Method.
The indirect method of calculating voltage regulation of synchronous machine can be further classified into 3 types:
1.EMF method or Synchronous impedance method.
2. MMF method or Ampere turn method.
3.Zero power factor method or Potier method.
Direct load test method for calculating voltage regulation of synchronous machine:
Now let’s see how to calculate voltage regulation of synchronous machine by using direct load test method:
Circuit diagram for calculating Voltage regulation of synchronous machine by direct load test:
