CPT Fluid Systems & Hydraulics Flashcards
6 cards from real CPT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 CPT Fluid Systems & Hydraulics flashcards as text
In a hydraulic system, what does a directional control valve control?
Answer: The path fluid takes through the circuit
A directional control valve routes hydraulic fluid to different actuator ports, controlling the direction of cylinder or motor movement.
Which hydraulic fluid property most affects the performance of a system at low temperatures?
Answer: Viscosity
Viscosity increases significantly at low temperatures, reducing pump efficiency and increasing pressure drop across lines and valves.
A hydraulic cylinder has a bore diameter of 4 inches and a rod diameter of 2 inches. Which side produces more force at equal pressure?
Answer: Bore (cap) side
The cap (bore) side has a larger effective area since no rod occupies it, so at equal pressure it produces more force than the rod side.
What is the primary reason for using a hydraulic filter with a bypass indicator?
Answer: To alert the technician when the filter element is clogged and fluid is bypassing filtration
When the filter element clogs, a bypass valve opens to maintain flow; the bypass indicator (pop-up or gauge) signals that the element needs replacement before contamination damages components.
Aeration in hydraulic fluid appears as which symptom during system operation?
Answer: Foamy or milky fluid with spongy actuator response
Entrained air creates foam and causes erratic, spongy actuator movement because air is compressible unlike hydraulic fluid.
What does ISO cleanliness code 16/14/11 represent in hydraulic fluid analysis?
Answer: Particle contamination levels at 4, 6, and 14 micron sizes
ISO 4406 cleanliness codes represent the number of particles per milliliter at three size thresholds (4µm, 6µm, 14µm), indicating contamination severity.