Hydraulics Review Flashcards
What are 4 things hydraulic fluid does?
Seals tight tolerances
Cools moving parts
Transmits power
Lubes moving components
What is viscosity?
Thickness of a fluid
What does temperature do to the viscosity of the fluid?
Low temperature makes fluid thicker
High temperature makes fluid thinner
What does AW stand for?
Anti- wear
What does WR stand for?
Wear resistant
What does EP stand for?
Extreme pressure additive
Is 32 weight fluid thinner or thicker than 46?
Thinner
What is cavitation?
Formation and collapse of air bubbles in the hydraulic fluid
Best idea temperature for hydraulic fluid?
Between 80°F-120°F
What is Pseudo cavitation?
Air leak drawing air into
The System
Are fire resistant fluids fire proof?
No
The temperature to which a fluid must be heated to give off vapor to ignite when a flame is applied?
Flash point
When a fluid is heated up enough to burn after a flame is applied?
Fire point
A fluid temperature at which it ignites without an external flame or spark
Auto ignition
What allows water and oil to mix?
Water-oil emulsion
What is phase separation?
When 2 fluids separate
What do you add to fluid in a low temperature environment to keep from freezing?
Water -glycol
What are some problems with synthetic fire resistant fluids?
Harmful to seals
Harmful to protective coatings
Foaming and air retention
Dirt retention
How should you store a drum or oil?
Somewhere warm
Store on its side
Remove dirt and debris from the lid before opening the lid up
What do hydraulic pumps do?
Convert the mechanical energy transmitted by its prime mover.
How do vane pumps work?
Draws in fluid as volume increases, fluid leaves pump as volume decreases
5 components of a vane pump?
Vanes, ring, shaft, rotor and a port plate
What does a fixed displacement pump need to operate?
Relief valve
How to control system pressure with a variable displacement pump?
Pump compensator
To have fluid flow volume must do what?
Volume must change
What is an issue with an unbalanced pump?
Thrust loading
What pump eliminates thrust loading issues?
Balanced pump
Advantage to cartridge style pumps?
Easy pump servicing
All variable volume and Pressure compensated pumps must have?
Case drain
How does a gear pump work?
Generates a pumping action by causing gears to mesh and unmesh
Name 5 types of pumps?
Vane
Gear
Double
Geroter
Piston
What would a flow meter on the case drain tell you?
If the flow goes up then that is a sign of the pump wearing out
Where does a case drain go?
Back to tank
What does a pump do?
Pulls fluid in the large volume area and pushes out the smallest volume area
What do motors do?
Pulls fluid in the smallest volume area and leaves at the largest volume area
Pressure equals?
Torque (force)
Flow equals?
RPM (speed)
Can all motors be pumps?
Yes
Can all pumps be motors?
No
Hydraulic motors are what style pumps?
Positive displacement
What are 5 hydraulic motors advantages
Instant reversing of motor shaft
Can be stalled without motor damage
Torque control throughout is operating speed
Dynamic braking easily accomplished
HP to weight ratio is better compared to electric motors
Regardless of pressure motor speed will?
Remain constant
How do you set a pressure compensator and relief valve?
