Motor Controls Unit 5
What is a primary resistor used for?
All of the answers above are correct.
When are the resistors of a primary resistor starter bypassed?
As the motor approaches its normal speed.
In the figure 5-5 circuit, what voltage is applied to the motor when the run indicator is lit?
Full Voltage.
What causes fast acceleration and damage to the driven machinery?
High starting torque.
How are the resistors connected?
In series with the motor terminals and power lines.
What is the effect of adding a ramp-down time?
Increases stopping time.
Which of the following characteristics is not an advantage of a soft starter compared to a primary resistor starter?
Larger heat losses.
In the figure 5-2 circuit, what control device is used to switch the run contactor on and off?
Selector Switch
The motor staring torque is proportional to the?
Square of motor voltage.
In the figure 5-5 circuit, what happens when the starting voltage is too low for the load?
the motor does not start easily.
