Motor drives can increase the speed of a motor without reducing ___.

Motor drives can increase the speed of a motor without reducing ___.

• A. Torque
• B. Current
• C. Induction
• D. Impedance

Answer: (A)

Motor drives raise speed by changing the supply frequency (and adjusting voltage) to control how fast the motor can rotate, while the torque remains determined by the current through the windings. The torque a motor produces is roughly proportional to current, so a drive can keep that current (and thus the torque) at its existing level even as speed increases. Since power equals torque times speed, increasing speed without lowering torque means the motor delivers more electrical power to meet the higher mechanical power demand—within the motor’s ratings. So, you can push the speed higher without reducing the torque output, as long as you stay within what the motor and drive can handle. The other terms—current, induction, and impedance—are not the aspects the drive tweaks to achieve a higher speed in this context; speed control is achieved primarily through frequency/voltage adjustments, not by inherently changing those other factors.

Motor drives raise speed by changing the supply frequency (and adjusting voltage) to control how fast the motor can rotate, while the torque remains determined by the current through the windings. The torque a motor produces is roughly proportional to current, so a drive can keep that current (and thus the torque) at its existing level even as speed increases. Since power equals torque times speed, increasing speed without lowering torque means the motor delivers more electrical power to meet the higher mechanical power demand—within the motor’s ratings.

So, you can push the speed higher without reducing the torque output, as long as you stay within what the motor and drive can handle. The other terms—current, induction, and impedance—are not the aspects the drive tweaks to achieve a higher speed in this context; speed control is achieved primarily through frequency/voltage adjustments, not by inherently changing those other factors.