Final answer:
The statement that large motors should be connected directly across the line on startup is False. It is advisable to use soft starters or motor starters to reduce the inrush current. The statement is False.
Step-by-step explanation:
The statement that large motors should be connected directly across the line on startup is False.
When a large motor is started, it draws a high current initially, which can cause voltage drops and other issues in the electrical system. To prevent this, large motors are often started using soft starters or motor starters, which gradually apply the voltage to the motor, reducing the inrush current.
By using soft starters or motor starters, the motor starts smoothly and with less stress on the electrical system.
It is false that large motors should be connected directly across the line on startup due to the risk of current surge. Large motors often use other methods to limit this surge, like reduced voltage starters. The power supplied to a truck's starter motor at 250 A and 24 V is 6000 Watts.
It is false that large motors should be connected directly across the line on startup. When a motor is first turned on, the back electromotive force (emf) is zero, allowing the motor to draw maximum current from the power source. This surge in current can cause significant voltage drops in the power lines, which is why lights in the same circuit may dim when high-power appliances are switched on. To minimize this effect, large motors often use reduced voltage starters or other soft-start mechanisms that gradually increase the voltage to limit the initial current surge.
The power supplied to the starter motor of a large truck that draws 250 A of current from a 24.0-V battery hookup would be calculated using the formula power (P) = voltage (V) × current (I), which in this case results in P = 24.0 V × 250 A, equating to 6000 Watts or 6.0 kW.