```
In [1]:
```%pylab inline

```
```

During a short-circuit test, a Y-connected synchronous generator produces 100 A of short-circuit armature current per phase at a field current of 2.5 A. At the same field current, the open-circuit line voltage is measured to be 440 V.

- Calculate the saturated synchronous reactance under these conditions.

If the armature resistance is $0.3\,\Omega$ per phase, and the generator supplies 60 A to a purely resistive Y-connected load ~~of 3 Ohms per phase at this~~ at a matching field current setting,

- Determine the voltage regulation under these load conditions.

```
In [2]:
```If = 2.5 # [A]
Vocc = 440.0 # [V]
Isc = 100.0 # [A]

Since this generator is Y-connected, the corresponding phase voltage is:

```
In [3]:
```Vphi = Vocc / sqrt(3)
print('Vphi = {:.0f} V'.format(Vphi))

```
```

and the armature current is $I_A = I_{SC}$ . Therefore, the saturated synchronous reactance is:

```
In [4]:
```Ia = Isc
Xs = Vphi / Ia
print('''
Xs = {:.2f} Ω
==========='''.format(Xs))

```
```

```
In [5]:
```Vl_desired = 440 # [V]
Ra = 0.3 # [Ohm]
Ia_b = 60.0 # [A]
EA = Vphi + Ra * Ia_b + Xs*1j * Ia_b
EA_angle = arctan(EA.imag/EA.real)
print('EA = {:.0f} V ∠{:.1f}°'.format(abs(EA), EA_angle/pi*180))

```
```

```
In [6]:
```Vl_nl = abs(EA) * sqrt(3)
print('Vl_nl = {:.0f} V'.format(Vl_nl))

```
```

The voltage regulation is:

$$VR = \frac{V_\text{T,nl} - V_\text{T,fl}}{V_\text{T,fl}} \cdot 100\%$$```
In [7]:
```VR = (Vl_nl - Vl_desired) / Vl_desired
print('''
VR = {:.1f} %
==========='''.format(VR*100))

```
```