Control device for heating deep-sea electric motor oil

摘要

A control device monitors the elapsed off time of an oil filled deep sea electric motor 4, and compares this with a calculated time for the oil temperature to drop to a predetermined value at a sensed water depth. When the two times are equal a low, heating current is supplied to the primary winding 11 to prevent the oil from becoming more viscous. The heating current is insufficient to rotate the motor armature, and its intensity is increased with depth corresponding to the decrease of the water temperature with depth.