| 摘要 |
FIELD: electrical engineering; governing speed of three-phase duel-speed motors. ^ SUBSTANCE: switching device has terminal of its one phase connected to those of interconnected like phases of motor two windings. Terminals of two other phases of mentioned device are connected to those of transfer contacts of second split-phase device. Terminals of breaking contacts of second switching device are connected to those of other phases of motor low-speed winding. Ground-fault pre-detecting unit is connected through breaking contact of first switching device to phase terminal of mentioned device directly connected to like phases of motor windings. Provision is made for reducing number of cable current-carrying conductors from six to three ones using only one ground-fault pre-detecting unit. ^ EFFECT: enhanced reliability and safety in operation, simplified design of device. ^ 2 cl, 2 dwg |
