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SELECTION OF CONDUCTORS

1912

4.Selection of current collectors

For choosing the current collector consider the total ampacity ( I
DK ) reduced by the duty cycle. a) When knowing each individual installed output according to 1 b) with one crane:b) When knowing total installed output according to 1 d) and e) with one I
DK = ∑ I
D crane: I
DK = I
DA = I
NK · ƒ
R Select suitable current collectors in accordance to the ampere capacities shown in the catalogue. c)If the ambient temperature is above +35°C, the permitted current collector load must also be reduced per correction factor( ƒ
T ) (Table 5). Permitted current collector load I
zul UT = I
zul · ƒ
T I
zul = Continuous capacity as shown in the catalogue

5.Calculation example

2 overhead travelling cranes together on a conductor line of 180 mlength.Voltage 400 V, No. of feeds: 3 Squirrel-cage three-phase motors, maximum ambient temperature + 40°C

➪

For review two parallel calculation processes have been drawn up: All individual output known:Only total installed output per crane known:Given:
➪ ➪ P Motor output ( P
N )Crane 1Crane 2Crane 1Crane 2Hoisting motorCrane chassisCross traversingBase load,lighting etc.110 kW, 60% ED37 kW, 40% ED30 kW, 40% ED8 kW, 100% ED90 kW, 60% ED22 kW, 40% ED15 kW, 40% ED4 kW, 100% ED
NK )185 kW131 kW Determining of rated currents ( I
N ): Either from Table 1 or with help of the formula: I P
N [kW]
· 1000
N = √ 3
· U[V]
· cos
N · Crane 1Crane 2Hoisting motorCrane chassisCross traversing Base load196 A68 A55 A 16 A160 A41 A29 A8 A Installed totaloutput ( I 185kW
· 1000
NK1 = √ 3
· 400 V
· 0.85
} · 0,85I
assumed NK1 = 369.6 AI 131kW
· 1000
NK2 = √ 3
· 400 V
· 0.85
} · 0,85I
assumed NK2 = 261.7 A Ampacity reduced by the duty cycle factor ( I
D ): I
D = I
N · ƒ
ED (from Table 2) I Crane 1Crane 2Hoisting motorCrane chassisCross traversing Base load
D = 196 A· 0.73 = 143.1 A I
D = 160 A· 0.73 = 116.8 A I
D = 68 A· 0.63 = 42.8 A I
D = 41 A· 0.63 = 25.8 A I
D = 55 A· 0.63 = 34.7 A I
D = 29 A· 0.63 = 18.3 A I
D = 16 A· 1 = 16 A I
D = 8 A· 1 = 8 A I
DK1 = 236.6 A I
DK2 = 168.9 A

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