单项选择题
A.Peak value B.Root-mean-square value C.Average value D.Maximum value
Fuses placed in series with a thermal trip-type circuit...
单项选择题Fuses placed in series with a thermal trip-type circuit breaker are used for （）.
A.time-delay protection B.short-circuit protection C.short duration surge protection D.sustained overload protection
The main difference between a motor control circuit con...
单项选择题The main difference between a motor control circuit containing low voltage protection and low voltage release is that the latter contains （）.
A.a magnetic operating coil B.normally open line contacts C.thermal-overload protection D.a momentary-contact start button
What will be the phase angle relationship of a six-pole...
单项选择题What will be the phase angle relationship of a six-pole, three-phase, rotating field generator （）.
A.60 B.120 C.180 D.360
