 | Circuits, Formulas and Tables Electrical Engineering - Basic vocational knowledge (Institut für Berufliche Entwicklung, 201 p.) |
 |  | 11. Basic symbols and formulas of electrical engineering |
|
|
11.6. Calculation of power
calculation of power losses
PV = power loss in per cent
direct current
|
|
[%] |
single-phase alternating current
|
|
[%] |
three-phase alternating current
|
|
[%] | | |
|
|
[V]; |
|
[V] |
|
|
[V]; |
|
[V] |
|
|
[V]; |
|
[V] |
Determination of a conductor cross-section
- Calculation of the rated current from current, voltage and power factor.- Division by all suitable current-carrying capacity factors of the Tables 9 to 12.
- Determination of the conductor cross-section according to the given current-carrying capacity factors after the calculated fictive current.
- Calculation of the conductor cross-sections according to the given power and voltage loss.
- Comparison of the cross-sections found out under the third and fourth point. The greatest is chosen as the cross-section to be installed.
Conversion of the measuring units of work and power
Work
|
J |
erg |
kpm |
kWh |
PSh |
kcal |
|
1 1 |
107 |
0.102 |
0.278 · 10-6 |
0.378 · 10-6 |
0.239 · 10-3 |
|
107 |
1 |
0.102 · 10-7 |
0.278 · 10-13 |
0.378 · 10-13 |
0.239 · 10-10 |
|
9.81 |
9.81 · 107 |
1 |
2.72 · 10-6 |
3.70 · 10-6 |
2.34 · 10-3 |
|
3.60 · 106 |
3.60 · 1013 |
3.67 · 105 |
1 |
1.36 |
860 |
|
2.65 · 106 |
2.65 · 1013 |
2.70 · 105 |
0.7355 |
1 |
632 |
|
4187 |
4.19 · 1010 |
427 |
1.16 · 10-3 |
1.58 · 10-3 |
1 |
Power
|
W |
kW |
kpm s-1 |
PS |
kcal s-1 |
kcal h-1 |
|
1 |
10-3 |
0.102 |
1.36 · 10-3 |
2.39 · 10-4 |
0.86 |
|
103 |
1 |
102 |
1.36 |
0.239 |
860 |
|
9.81 |
9.81 · 10-3 |
1 |
0.0133 |
2.34 · 10-3 |
8.43 |
|
735.5 |
0.7355 |
75 |
1 |
0.1757 |
632 |
|
4187 |
4.19 |
427 |
5.69 |
1 |
3600 |
|
1.16 |
1.16 · 10-3 |
0.119 |
1.58 · 10-3 |
2.78 · 10-4 |
1 |
