A motor control system includes a motor switching assembly comprising a power converter positioned on a converter path, a first relay positioned on the converter path upstream of the power converter, a second relay positioned on a bypass path that is in parallel with the converter path, and a solid-state switching unit positioned upstream from the converter path and the bypass path. The motor control system also includes a control system that controls operation of the motor switching assembly, with the control system programmed to operate the solid-state switching unit in one of a conducting mode, a non-conducting mode, and a ramping mode, so as to selectively control and condition power flow therethrough. The control system is also programmed to control switching of the first and second relays between open and closed positions to selectively route power along the converter path or the bypass path.

A motor control system includes a motor switching assembly comprising a power converter positioned on a converter path, a first relay positioned on the converter path upstream of the power converter, a second relay positioned on a bypass path that is in parallel with the converter path, and a solid-state switching unit positioned upstream from the converter path and the bypass path. The motor control system also includes a control system that controls operation of the motor switching assembly, with the control system programmed to operate the solid-state switching unit in one of a conducting mode, a non-conducting mode, and a ramping mode, so as to selectively control and condition power flow therethrough. The control system is also programmed to control switching of the first and second relays between open and closed positions to selectively route power along the converter path or the bypass path.

A motor starter apparatus includes an enclosure, a bypass contactor configured to be installed in the enclosure and configured to selectively couple a power source to a motor, and a reduced voltage soft starter (RVSS) circuit assembly (e.g. a wheeled truck) configured to be installed in the enclosure, to be coupled to the power source and to apply a variable voltage to the motor. The bypass contactor is configured to preserve a connection of the bypass contactor to the power source and the motor when the RVSS circuit assembly is removed from the enclosure.

The invention relates to a soft starter (10) for connecting at least one main circuit (12, 14, 16), each of which includes a bypass circuit (20) having a semiconductor switch (22). Said soft starter (10) comprises a control unit (40) for actuating the bypass circuit (20), and the control unit (40) is equipped with a control signal input (44). According to the invention, the control unit (40) has a separate safety signal input (42).

The invention relates to a soft starter (10) for connecting at least one main circuit (12, 14, 16), each of which includes a bypass circuit (20) having a semiconductor switch (22). Said soft starter (10) comprises a control unit (40) for actuating the bypass circuit (20), and the control unit (40) is equipped with a control signal input (44). According to the invention, the control unit (40) has a separate safety signal input (42).

A drive control method is applicable to a drive system including a driver, a bus and a motor, the motor being directly connected to the bus in a first connection mode or connected to the driver in a second connection mode. The drive control method includes the driver feeding an electric signal to the motor through the output port and simultaneously detecting its own actual output feature; and the driver determining whether the output port is connected to the bus according to the actual output feature. Upon the output port being determined not to be connected to the bus, the driver starts the motor normally. Upon the output port being determined to be connected to the bus, the driver disconnects the output port. In addition, a corresponding drive system, a processing system and a storage medium are disclosed.

An AC-AC power converter, such as a motor soft starter, includes an input connectable to an AC source with a disconnect switch, an output connectable to an AC load, and phase lines connecting the input and output to transmit power. In-line solid-state switching blocks are connected between line terminals and load terminals of the AC source and AC load, respectively, such that each phase line includes a solid-state switching block connected thereto. Free-wheeling solid-state switching blocks are connected to the load terminals at one end and together at a common connection at another end, such that each phase line includes a free-wheeling solid-state switching block connected thereto. Each of the in-line and free-wheeling solid-state switching blocks comprises a bi-directional switching block that selectively controls current and withstands voltage in both directions. The switching blocks also provide soft-starter functions, variable speed control, and integrated circuit breaker protection capability.

An AC-AC power converter, such as a motor soft starter, includes an input connectable to an AC source with a disconnect switch, an output connectable to an AC load, and phase lines connecting the input and output to transmit power. In-line solid-state switching blocks are connected between line terminals and load terminals of the AC source and AC load, respectively, such that each phase line includes a solid-state switching block connected thereto. Free-wheeling solid-state switching blocks are connected to the load terminals at one end and together at a common connection at another end, such that each phase line includes a free-wheeling solid-state switching block connected thereto. Each of the in-line and free-wheeling solid-state switching blocks comprises a bi-directional switching block that selectively controls current and withstands voltage in both directions. The switching blocks also provide soft-starter functions, variable speed control, and integrated circuit breaker protection capability.

A motor starter includes a plurality of semiconductor switches configured to couple respective phases of an AC power source to respective phases of a motor and a control circuit configured to configured to selectively operate the semiconductor switches to gradually increase a voltage applied to the motor, to determine root mean square (RMS) current values of a current of the motor as the voltage increases, and to cause the semiconductor switches to apply a full voltage or a more steeply ramping voltage to the motor responsive to the RMS current values meeting a criterion.

A motor starter includes a plurality of semiconductor switches configured to couple respective phases of an AC power source to respective phases of a motor and a control circuit configured to configured to selectively operate the semiconductor switches to gradually increase a voltage applied to the motor, to determine root mean square (RMS) current values of a current of the motor as the voltage increases, and to cause the semiconductor switches to apply a full voltage or a more steeply ramping voltage to the motor responsive to the RMS current values meeting a criterion.