Synchronous Reactance of \Delta-connected SG is obtained as:
Select one:
\(a.\frac{V_{T,oc}}{I_f L_{sc}}\) at rated $I_f$
\(b.\frac{V_{T,oc}}{\sqrt{3}I_f L_{sc}}\) at constant $I_f$ in linear region of OCC
\(c.\frac{\sqrt{3}V_{T,oc}}{I_f L_{sc}}\) at constant $I_f$ in linear region of OCC
\(d.\frac{V_{T,oc}}{\sqrt{3}I_f L_{sc}}\) at constant $I_f$ in non-linear region of OCC
The maximum Torque in SM occurs when:
Select one:
\(a.\delta = 90^\circ\)
\(b.\delta = 22^\circ\)
\(c.\delta = 0^\circ\)
\(d.\delta = 30^\circ\)
When the field current in the synchronous motor decreased
Select one:
\(a. T_{max}\) and PF will not affected
b. motor become more stable and PF improved from lagging to leading
c. motor vibrate and PF changed from leading to unity to lagging
\(d. T_{max}\) and PF will increased
\(e. T_{max}\) and PF will decreased
The starting current of three phase Induction Motor of a 20hp, 200V, code-letter D (4-4.5kVA/hp):
Select one:
a. 74.6A
b. 10.39kA
c. 259.8A
d. 43A
