Which devices convert AC to DC specifically for motor control?

The devices that convert AC to DC specifically for motor control include SCR drives and VVVF drives. SCR (Silicon Controlled Rectifier) drives utilize thyristors to convert alternating current (AC) into direct current (DC), which can then be used to control the speed and torque of a DC motor effectively. This type of drive provides precise control over the motor's performance by adjusting the voltage and current supplied to the motor.

VVVF (Variable Voltage Variable Frequency) drives, on the other hand, are primarily used with AC motors. While they do not directly convert AC to DC, they control the power supplied to AC motors by converting AC into a DC intermediate stage, allowing for variable frequency and voltage output tailored for motor control purposes. The entire process enables efficient motor operation at various speeds, promoting energy savings and better performance.

The other options do not perform the same function regarding the conversion of AC to DC for motor control. Synchronous motors operate on the principle of synchronizing their rotor speed with the supply frequency and do not convert AC to DC. Dashpots are mechanical devices used primarily for controlling motion and do not involve electrical current conversion. Transformers are designed to change voltage levels in AC circuits but do not convert AC to DC. Thus, SCR