Which statement about keypad adjustable frequency controls is true?

Which statement about keypad adjustable frequency controls is true?

• A. They cannot be programmed for soft start or stop
• B. They can be programmed for soft start or stop
• C. They require hydraulic power
• D. They are obsolete

Answer: (B)

Keypad adjustable frequency controls control motor speed by varying the electrical frequency and voltage fed to the motor. Because you can set how quickly the frequency ramps up or down, these drives can perform soft starts and soft stops. That means the hoist and trolley accelerate and decelerate gradually rather than slam to a stop or surge to speed, which protects gears, ropes, and loads and gives the operator smoother control. The keypad is used to program those ramp rates and other parameters (like max speed and acceleration time), so this capability is a built-in feature of these drives. They don’t rely on hydraulic power; they operate electrically, and they’re not obsolete—modern cranes often use these drives for smoother, safer operation. So, the statement that they can be programmed for soft start or stop is true and best.

Keypad adjustable frequency controls control motor speed by varying the electrical frequency and voltage fed to the motor. Because you can set how quickly the frequency ramps up or down, these drives can perform soft starts and soft stops. That means the hoist and trolley accelerate and decelerate gradually rather than slam to a stop or surge to speed, which protects gears, ropes, and loads and gives the operator smoother control.

The keypad is used to program those ramp rates and other parameters (like max speed and acceleration time), so this capability is a built-in feature of these drives. They don’t rely on hydraulic power; they operate electrically, and they’re not obsolete—modern cranes often use these drives for smoother, safer operation.

So, the statement that they can be programmed for soft start or stop is true and best.