A worker opens a circuit breaker and expects this action to shut down a specific motor, but the equipment continues to run. The best course of action is to _____.
a. stop and obtain further direction before proceeding
b. close and then open the breaker again
c. move the breaker to the reset position
d. assume the breaker has been mislabeled, so open nearby breakers until the correct one is located
a. stop and obtain further direction before proceeding
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Complete the field notes from the given data. Check your final answer mathematically, as described in this chapter.
What will be an ideal response?
In a radial distribution system, the central station supplies power to the various ____.
A. substations B. loops C. residential units D. industrial installations
A dc, separately excited motor has the following data:
Rated field voltage = 300 V Field constant (K?) = 3 Vs Armature resistance = 2 ? Field resistance = 150 ? The motor is used to drive an assembly line consisting of a conveyor belt moving horizontally. The load on the belt varies depending on the amount of goods being moved. The load torque seen by the motor varies from a maximum of 24 Nm to a minimum of 3 Nm. At all loading conditions, the speed of the motor must be maintained constant and equal to 200 rpm. a. To achieve the required operation, the armature voltage of the motor is adjusted by a single-phase, full-wave, ac/dc converter. The input to the converter is 240 V (rms). Calculate the range of the triggering angle (minimum and maximum) required to maintain the motor speed at the specified value at all loading conditions. Assume that the armature current is always continuous. b. Another method to achieve the desired operation is to adjust the field voltage. In this case, the armature voltage can be kept constant at some value. Calculate the range of the field voltage (minimum and maximum). Hints: Assume that the maximum value of the field voltage is equal to its rated value (i.e., 300 V). Also assume that the field constant (K?) is linearly proportional to the field voltage.
________ fours, in which two improvising instrumentalists play solo parts on alternating four bars.
Fill in the blank(s) with correct word