poster - International Conference of Agricultural Engineering

the inverter that provides a reference voltage, which regulates the motor speed proportional to
this reference voltage.
After the system installation of Figure 1 be implanted in the laboratory, a test was
performed to verify energy consumption with the use of the main line for all possible
combinations (15 in total) of the four lots according to be irrigating (on) or not (off), due to the
fact that the irrigation system without the use of the inverter, in general, have a constant
energy consumption.
For each combination was checked the flow and pressure for each outlet pressure after
the pump and before each record of the lot. Later, it was performed again the 15 combinations,
but this time using the frequency inverter that, due to the rotation decrease, kept the pressure
of 15 MCA for the more critical lot of the combination. For the situations was recorded the
power consumed, reactive power, power factor and rotation of the motor shaft by means of a
tachometer.
1.2 Results and Discussion
With the simulation were found the values of pressure for motor-pump and for each
outlet pressure before leaving the lots, being these values obtained for each combination of
open and close of the record possible in the assembled district, as shown in Table 1.
After found the pressures that could be in a real perimeter using the simulation, in a
laboratory assembled a prototype and by the pressure drops register, assembled these
pressures for each combination. As far as using only the engine or using motor coupled to the
frequency inverter, always with a flow rate of 2.5 m 3 .h -1 .
Table 1- Values found with the simulation for each point of record of each possible
combination.
Open Records in
Points of outlet pressure (mca)
the lots
Combinations
1 2 3 4 Pump Record 1 Record 2 Record Tomada 31
Record 4
1 X X X X 32.08 22.73 19.87 17.46 15.34
2 X X X - 33.16 26.05 23.64 21.52 19.52
3 X X - X 33.16 26.05 23.64 21.52 19.41
4 X - X X 33.16 26.05 23.64 21.23 19.12
5 - X X X 33.16 26.05 23.18 20.77 18.66
6 X X - - 33.92 29.96 27.85 26.35 24.35
7 X - X - 33.92 28.46 26.35 24.24 22.24
8 X - - X 33.92 28.46 26.35 24.24 22.12
9 - X X - 33.92 28.46 26.05 23.94 21.94
10 - X - X 33.92 28.46 26.05 23.94 21.83
11 - - X X 33.92 28.46 26.05 23.65 21.53
12 X - - - 34.36 29.96 27.96 25.96 23.96
13 - X - - 34.36 29.96 27.85 25.85 23.85
14 - - X - 34.36 29.96 27.85 25.74 23.74
15 - - - X 34.36 29.96 27.85 25.85 23.85
(X )for opened record, (-) for closed record