DDE-1000/4000 HP Q634 General Subjects Flashcards
In a closed-loop process control system featuring negative feedback, what is the function of the error detector within the controller?
The error detector computes the difference between the measured value of the controlled variable and the desired value (set point).
Which of the wave shapes shown in the illustration is termed a sinusoidal wave? Illustration EL-0088
A
Which of the following fixed temperature heat-actuated fire detectors is the most prone to false alarms?
bimetallic strip detector
What statement is true concerning the electrical diagram shown in figure “B” of the illustration? Illustration EL-0019
“R1”, “R2”, and “R3” are connected in parallel.
A precharged bladder-type accumulator used in a hydraulic system, can be potentially dangerous if __________.
the charging valve stem breaks while at normal working pressure
Three 12 volt, lead-acid, batteries connected in series will develop how many volts?
36 volts
If an air compressor is fitted with a hand-off-auto (H-O-A) control station, what statement concerning operation is true?
In the hand mode, the compressor will run continuously with unloading.
Which of the following statements is true concerning the gauge labeled “A” of the illustrated gauge manifold set? Illustration GS-RA-01
The gauge labeled “A” is a compound gauge and is usually color-coded blue.
What statement is true concerning the construction of watertight bulkheads?
The strakes of the bulkhead are horizontal and the stiffeners are vertical and the bulkhead must have increasingly greater strength towards the base.
Both the direction of flow and fluid flow rate of a variable displacement radial piston pump are determined by the relative positions of the __________.
floating ring and cylinder body
When troubleshooting a lead-acid storage battery, what is the best method for detecting a weak or dead cell?
comparing the specific gravity of the electrolyte in each cell
In a two-stage centrifugal air conditioning system, the liquid refrigerant passes through the condenser directly to what component?
economizer
When a refrigeration compressor is in the “off” cycle, the thermal expansion valve will react in what way?
it will continue to function as a result of the net balance of forces acting on the diaphragm
As shown in the illustrated diagnostic setup for locating a shorted field coil of a ten-pole synchronous motor, if 240 VAC/60 Hz is applied across the brushes, what would be the individual voltage drops measured across each field coil assuming that none of the field coils are shorted? Illustration EL- 0202
24 VAC
On a modern refrigerated container unit employing suction modulation for the purposes of capacity control and capacity limitation, what happens when the applied voltage and current draw associated with the normally open (NO) suction modulation valve located in the suction line both increase?
the valve will further close, raising evaporator pressure and lowering suction pressure
Alkyl benzene ISO 32 cSt synthetic refrigerant oil is miscible and suitable to use with which of the following refrigerants?
R-22