A motor control apparatus includes: a main power conversion circuit that converts power that is supplied from a power supply into alternating current power for driving a motor, and outputs the alternating current power; a counter electromotive force protection circuit including a rectifier unit that rectifies alternating current power based on counter electromotive force of the motor and outputs direct current power, a short-circuit unit that short-circuits terminals on a direct current output side of the rectifier unit, and an alarm signal output unit that outputs an alarm signal at occurrence of an abnormality; a monitoring unit that monitors whether the alarm signal is output from the alarm signal output unit; and a protection operation unit that performs a protection operation for preventing damage to the main power conversion circuit when the monitoring unit determines that the alarm signal is output from the alarm signal output unit.

A system may include a power supply that generates a first voltage. The power supply may couple upstream from an electrical load. The electrical load may operate based at least in part on the first voltage. In some cases, a solid-state circuit breaker may be coupled between the power supply and the electrical load. Furthermore, a control system may be communicatively coupled to the power supply, the electrical load, and the solid-state circuit breaker. The control system may receive an operational status from the solid-state circuit breaker and may update a visualization rendered on a graphical user interface based at least in part on the operational status. The operational status may indicate an operation of the solid-state circuit breaker coupling the power supply to the electrical load.

An induction motor overheat monitoring method and device detects overheating of an induction motor from a detection value of a current sensor. A resistance calculation relationship data indicating a relationship between a resistance and a feature amount at the time of starting of the induction motor and a determination reference value for determining overheating are stored in advance. At each starting, a current of the induction motor is detected, a signal regarding a phase angle difference is calculated, and a feature amount of the motor is calculated from the signal regarding the phase angle difference. Further, a resistance of the induction motor is calculated by using the feature amount of the motor and the resistance calculation reference data stored in advance. Then, a temperature of the induction motor is calculated from the resistance of the induction motor, and it is determined if the motor is overheated.

The systems and methods disclosed relate to arc resistant medium voltage motor control centers. A drive control system comprises a variable frequency drive cabinet comprising a variable frequency drive; a power supply line; and at least one motor control cabinet having a top portion and a bottom portion, wherein the at least one motor control cabinet comprises: a medium voltage fused bypass controller in the bottom portion; a medium voltage non-fused transfer controller in the top portion; a first door disposed within the bottom portion; a second door disposed within the top portion; and an air vent, wherein the air vent is disposed in the first door, wherein the first door, the second door, and the air vent are arc resistant; wherein the variable frequency drive is coupled to the power supply line and the non-fused transfer controller and the fused bypass controller is coupled to the power supply line.

An apparatus is disclosed that in one embodiment includes a circuit configured to selectively activate a transistor. The circuit is further configured to assert a signal when the circuit detects an electrical short between terminals of the transistor or when the circuit detects the transistor does not conduct current while the transistor is activated by the circuit. The circuit is further configured to output another signal, which is set to a first state or a second state. The other signal is set to the first state when the circuit detects the electrical short. The other signal is set to the second state when the circuit detects the transistor does not conduct current while activated.

A dual motor system includes a first motor providing a lower speed range and a second motor providing a higher speed range, wherein the motors are coaxially arranged and aligned on and drive a common shaft, and a motor control system controlling the speed of the first motor and engaging the second motor as needed. The first motor is a variable speed motor providing a lower two-thirds of a full speed range, and the second motor is an induction motor providing the upper one-third in the form of one or more discrete fixed speeds. The system may include a transformer including a first winding tap which provides a first higher speed, and a second winding tap which provides a second higher speed. The system may also include a flow control system for automatically controlling the speed of the motors for particular applications, such as flow control in a pool.

The systems and methods disclosed relate to arc resistant medium voltage motor control centers. A drive control system comprises a variable frequency drive cabinet comprising a variable frequency drive; a power supply line; and at least one motor control cabinet having a top portion and a bottom portion, wherein the at least one motor control cabinet comprises: a medium voltage fused bypass controller in the bottom portion; a medium voltage non-fused transfer controller in the top portion; a first door disposed within the bottom portion; a second door disposed within the top portion; and an air vent, wherein the air vent is disposed in the first door, wherein the first door, the second door, and the air vent are arc resistant; wherein the variable frequency drive is coupled to the power supply line and the non-fused transfer controller and the fused bypass controller is coupled to the power supply line.

A solid-state circuit breaker (SSCB) with self-diagnostic, self-maintenance, and self-protection capabilities includes: a power semiconductor device; an air gap disconnect unit connected in series with the power semiconductor device; a sense and drive circuit that switches the power semiconductor device OFF upon detecting a short circuit or overload of unacceptably long duration; and a microcontroller unit (MCU) that triggers the air gap disconnect unit to form an air gap and galvanically isolate an attached load, after the sense and drive circuit switches the power semiconductor device OFF. The MCU is further configured to monitor the operability of the air gap disconnect unit, the power semiconductor device, and other critical components of the SSCB and, when applicable, take corrective actions to prevent the SSCB and the connected load from being damaged or destroyed and/or to protect persons and the environment from being exposed to hazardous electrical conditions.

A load protection system and a method of protecting a load. The load protection system includes a PLC transmitter module and a PLC receiver module, which are configured to communicate a plurality of bits of data, each bit transmitted near a zero-crossing of a voltage on the power lines supplying power to the load, in the form of a high frequency burst of pulses. The pulses are structured in two patterns. The first pattern serves to identify the start of the second pattern, and the second pattern includes the data. The first pattern is unique and not represented within the second pattern. The load may be a motor, and the data may include a parameter value representing a parameter of the motor.

Fault-tolerant electrical drive systems and methods of maintaining electrical balance or continuing operation of a rotary electric machine under a fault condition are provided. One such system comprises: a rotary electric machine comprising pn phases having a common connection point, where p is a prime number and n is an integer greater than or equal to 1; a drive circuit module having pn phase drive circuits and a reserve drive circuit; and a contactor module. The contactor module comprises: pn phase contactors each of which is operable to connect one of the pn phases of the rotary electric machine to a respective one of the pn phase drive circuits; and a phase fault contactor operable to connect the reserve drive circuit to the common connection point.