A brushed DC motor can control speed by varying what?
A Gear tooth count
B Applied voltage
C Fluid viscosity
D Sensor resolution
Answer: B. Applied voltage. DC motor speed is controlled by armature voltage or pulse-width modulation.
A BLDC motor uses what instead of mechanical brushes?
A Electronic commutation
B Hydraulic valves
C Slip belts
D Fuel injection
Answer: A. Electronic commutation. Brushless DC motors switch phase currents electronically.
A stepper motor moves in what increments?
A Uncontrolled continuous slip
B Discrete angular steps
C Linear pulses only
D Random angles
Answer: B. Discrete angular steps. Stepper motors rotate by commanded step angles.
A servo motor system typically uses what?
A No position feedback
B Closed-loop feedback
C Manual steering only
D Open fluid loop
Answer: B. Closed-loop feedback. Servo systems use feedback to control position, speed or torque.
An induction motor develops torque through what interaction?
A Permanent gear mesh
B Hydraulic pressure
C Combustion gas
D Induced rotor current
Answer: D. Induced rotor current. The rotating stator field induces rotor currents that produce torque.
A synchronous motor rotor turns at what relative to field?
A Synchronous speed
B Half synchronous speed
C Zero speed
D Slip speed always
Answer: A. Synchronous speed. A synchronous motor locks rotor speed to the rotating magnetic field.
A gear reducer trades output speed for what?
A Lower torque always
B No speed change
C Higher torque
D Higher frequency
Answer: C. Higher torque. Reduction gearing lowers speed and increases torque ideally.
A ball screw converts rotary motion into what?
A Thermal energy
B Pressure signal
C Linear motion
D Digital code
Answer: C. Linear motion. A ball screw provides efficient rotary-to-linear motion.
A hydraulic actuator uses pressurized what?
A Compressed air only
B Electrical charge
C Solid springs only
D Liquid
Answer: D. Liquid. Hydraulic actuators use pressurized fluid to generate force and movement.
A pneumatic actuator uses what working medium?
A Hydraulic oil only
B Steam only
C Solid fuel
D Compressed air
Answer: D. Compressed air. Pneumatic actuators use compressed air or gas.
A solenoid converts electrical current into what?
A Fluid filtration
B Temperature reading
C Linear motion
D Gear reduction
Answer: C. Linear motion. A magnetic field from a coil moves a plunger.
A relay uses a coil to switch what?
A Electrical contacts
B Mechanical gear teeth
C Hydraulic pistons
D Sensor optics
Answer: A. Electrical contacts. An energized coil moves contacts to switch another circuit.
A MOSFET is commonly used as what electronic component?
A Pressure sensor
B Gearbox
C Power switch
D Temperature standard
Answer: C. Power switch. MOSFETs efficiently switch electrical power in motor drives and converters.
An H-bridge can reverse what direction?
A Sensor calibration
B Fluid flow only
C DC motor rotation
D AC frequency directly
Answer: C. DC motor rotation. An H-bridge reverses voltage polarity across a DC motor.
PWM controls average motor voltage by changing what?
A Gear ratio
B Battery chemistry
C Sensor resolution
D Duty cycle
Answer: D. Duty cycle. Pulse-width modulation changes the fraction of time a switch is on.
An inverter converts DC power into what?
A Hydraulic pressure
B Mechanical force
C Temperature signal
D AC power
Answer: D. AC power. An inverter switches DC input to create AC output.
A rectifier converts AC into what?
A DC power
B Rotary motion
C Pressure pulses
D Heat only
Answer: A. DC power. Rectifiers use diodes or controlled switches to produce DC from AC.
A buck converter reduces what electrical quantity?
A Mechanical torque
B DC voltage
C Sensor range
D AC frequency only
Answer: B. DC voltage. A buck converter steps DC voltage down.
A battery-management system monitors cell voltage and what?
A Temperature
B Gear backlash
C Air humidity only
D Valve lift
Answer: A. Temperature. A BMS monitors voltage, current and temperature to protect battery cells.
A regulated power supply maintains what output?
A Variable gear speed
B Specified voltage
C Hydraulic flow
D Unfiltered sensor noise
Answer: B. Specified voltage. A regulated supply maintains output voltage despite input or load variation.
A PID controller uses proportional, integral and what action?
A Derivative
B Differential gear
C Digital filter only
D Direct current
Answer: A. Derivative. PID combines proportional, integral and derivative terms.
Proportional control output responds to current what?
A Accumulated error
B Error rate
C Error
D Sensor temperature only
Answer: C. Error. The proportional term scales the present error.
Integral control responds to accumulated what?
A Current speed only
B Error derivative
C Machine position only
D Error
Answer: D. Error. The integral term accumulates error over time.
Derivative control responds to rate of change of what?
A Error
B Accumulated position
C Output voltage only
D Sensor range
Answer: A. Error. The derivative term reacts to how quickly the error changes.
A motor drive can limit current to protect what?
A Machine color
B Motor windings
C Gear ratio
D Toolpath
Answer: B. Motor windings. Current limiting protects motor and power electronics from overload.