Explain the purpose of the field discharge resistor.
What will be an ideal response?
To shut down the motor, the field circuit is deenergized by opening the field discharge switch. As the field flux collapses, a voltage is induced in the field windings. This voltage may be large enough to damage the insulation of the windings. To prevent such a high voltage, the field discharge resistor is connected across the field circuit. As a result, the energy stored in the magnetic field is spent in the resistor and a lower voltage is induced in the field circuit.
You might also like to view...
An L-header is best described as _____.
a. one or two angled pieces fitted over the top track b. two C-shapes with webs touching each other c. four angled pieces engineered for extra heavy loads d. four C-shapes seated in the tracks like a box
What prevents cold air from being circulated to the heated space during the defrost cycle?
A. The auxiliary heater turns on to "temper" the air. B. All of the dampers close automatically. C. The indoor fan motor turns off. D. Both a and b are correct.
What are the two OSHA classes that are commonly offered to construction workers?________________________________________________________________________
What will be an ideal response?
The overall envelope of perfect form within which the feature would just fit is referred to as ____.
A. virtual condition B. maximum material condition C. virtual form D. virtual size