Hydraulics & Pneumatics Systems Flashcards
6 cards from real Amazon Maintenance Technician practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Hydraulics & Pneumatics Systems flashcards as text
What condition is indicated by milky or cloudy hydraulic fluid?
Answer: Water or air contamination in the fluid
Milky or cloudy hydraulic fluid indicates water contamination or aeration, both of which reduce lubrication and can cause cavitation.
What is cavitation in a hydraulic pump, and what typically causes it?
Answer: Formation and collapse of vapor bubbles caused by low inlet pressure
Cavitation occurs when inlet pressure drops below the fluid's vapor pressure, forming bubbles that collapse violently and erode pump components.
In a pneumatic system, what is the purpose of the lubricator in the FRL unit?
Answer: Inject oil mist to lubricate downstream components
The lubricator in the Filter-Regulator-Lubricator unit injects a fine oil mist into the air stream to lubricate valves, cylinders, and other pneumatic components.
Which type of hydraulic cylinder produces force in one direction and relies on gravity or a spring for the return stroke?
Answer: Single-acting cylinder
A single-acting cylinder applies hydraulic force in one direction only; the return is accomplished by spring tension or gravity.
What OSHA standard governs the lockout/tagout of hydraulic energy sources before maintenance?
Answer: 29 CFR 1910.147
OSHA 29 CFR 1910.147, the Control of Hazardous Energy standard, requires hydraulic systems to be de-energized and depressurized before maintenance work begins.
A solenoid-operated pneumatic valve hums but does not shift. What is the most likely cause?
Answer: Spool sticking due to contamination or insufficient voltage to fully shift the spool
Humming indicates the solenoid coil is energized but insufficient voltage or a sticky spool prevents the valve from fully shifting.