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
单项选择题 What will be the phase angle relationship of a six-pole, three-phase, rotating field generator （）.
单项选择题 The part of a fuse that melts and opens the circuit is made of （）.
单项选择题 Time delayed or delayed action-type fuses are designed to （）.
