32 lines
No EOL
1.3 KiB
Markdown
32 lines
No EOL
1.3 KiB
Markdown
# Skyler MacDougall
|
|
|
|
## Homework 6: due 2/26/2020
|
|
|
|
7. A single-phase transformer has a rating of 100kVA, 7200V-600V, 60Hz. If it is reconnected as an autotransformer having a ratio of 7800V-7200V, calculate the load it can carry.
|
|
|
|
$$
|
|
100kVA= S;\ 7200V = V_1;\ 600V=V_2\\
|
|
100kW=P_1
|
|
$$
|
|
|
|
8. In the above problem, How should the transformer terminals ($H_1$, $H_2$, $X_1$, $X_2$) be connected?
|
|
|
|
$$
|
|
-
|
|
$$
|
|
|
|
14. Many airports use series lighting systems in which the primary windings of a large number of current transformers are connected in series across a constant current, 60Hz source. In one installation, the primary current is kept at 20A. The secondary windings are individually connected to a 100W, 6.6A incandescent lamp.
|
|
1. Calculate the voltage across each lamp.
|
|
$$
|
|
|
|
$$
|
|
|
|
2. The resistance of the secondary winding is $0.07\Omega$ while that of the primary is $0.008\Omega$. Knowing that the magetizing current and the leakage reactance are both negligible, calculate the voltage across the primary winding of each transformer.
|
|
$$
|
|
|
|
$$
|
|
|
|
3. If 140 lamps, spaced at 50m intervals, are connected in series using No. 14 wire, calculate the minimum voltage of the power source. Assume the wire operates at a temperature of $105^\circ C$.
|
|
$$
|
|
|
|
$$ |