单项选择题
A device which prints out a permanent record of the plant operating conditions is known as the （）.
A.analogger B.bell logger C.alarm logger D.data logger
单项选择题 Which of the following types of motors is often designed for use in correcting power factor?（）
单项选择题 Power transformers are rated in （）.
单项选择题 The purpose of DC generator brushes is to （）.
