Unit 2_02 Electrical

9/12/2021

 Delta or Mesh Connection

 If the six ends of three phases are so connected
that one end of first coil is connected to start
end of the second coil and so on, a closed mesh
will be formed.

 If three lines are taken from the three connected
points, then this method is called delta
connection.

 As only one phase winding is in between any two
lines, phase voltage will be equal to the line
voltage.

 ℎ =

 ℎ =
3

 Therefore, 3 ℎ = 3

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 The wattmeter is used to measure the power
of three phase supply.

 There are

 One wattmeter method
 Two wattmeter method
 Three wattmeter method

 In common, two wattmeter method is used
for balanced or imbalance load.

 In this method the wattmeter W1 and W2 are
separately connected to three phase circuit.

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 In wattmeter, there are two coils

 M and L are represent the current coil
 V1 and V2 are represent the pressure coil.

 The current coil of Wattmeter W1 is
connected in series with R and the pressure
coil is connected between R and B.

 The current coil of Wattmeter W2 is
connected in series with Y and the pressure
coil is connected between Y and B.

 Similarly, two watt meters may be connected
to Delta connection to measure the total
power.

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