301A: Hydraulic Principles Flashcards
(55 cards)
List four advantages of hydraulic control in heavy equipment machinery
functions.
a) Relatively compact
b) Installation is more flexible than mechanical
c) Cooling and lubrication is easy to accommodate
d) Easily control several functions at one time
301A: Pg. 2
List four disadvantages of hydraulic control in heavy equipment machinery
functions.
a) Fluids under pressure can result in personal injury or death if not handled
safely.
b) There is always some noise produced by the system.
c) Oil leakage is a source of contamination and fire.
d) Temperature variations (too high or low) effect component reliability and
machine performance.
301A: Pg. 2
Work is defined as a:
Force acting through a distance
301A: Pg. 2
Force is the push or pull that is capable of producing or changing the motion of a body (T/F)
True
301A: Pg. 2
Energy is defined as:
The ability to do work
301A: Pg. 4
List four common forms of energy.
a) mechanical energy
b) hydraulic energy
c) heat energy
d) electrical energy
301A: Pg. 4
The law of conservation of energy states that:
Energy cannot be created or destroyed.
301A: Pg. 4
In an engine, chemical energy in the fuel is converted to mechanical energy in the
engine combustion chamber. (T/F)
False; Chemical energy in the fuel is converted to heat energy in the
combustion chamber.
301A: Pg. 4
A hydraulic actuator converts energy from what form to what form?
Hydraulic energy into mechanical energy.
Kinetic energy in a hydraulic system is created by:
The rate of oil flow through a system
301A: Pg. 5
Potential energy in a hydraulic system is responsible for creating:
a) force
b) motion
c) actuator speed
d) mechanical energy
a) Force
301A: Pg. 5
Laminar flow refers to:
When oil flows through a system in straight parallel flow paths.
List three conditions that could result in turbulent hydraulic flow
- Conductors that are too small
- Abrupt changes in conductor cross-section
- Abrupt changes in flow direction
301A: Pg. 10
Excessively turbulent flow in a hydraulic system will result in excessive:
Pressure losses (lost as heat)
301A: Pg. 10
Hydraulic actuators that are connected in series will have the same pressure applied to each actuator. (T/F)
False; Pressure applied to each actuator will vary while flow remains constant.
301A: Pg. 12
Actuators connected in series provide:
A) High torque, limited speed
B) High torque, high speed
C) Limited torque, high speed
D) Low power losses
C) limited toque, high speed.
Describe the pressure and flow characteristics of a hydraulic circuit that has multiple actuators connected in parallel.
a) Pressure characteristics are ________
b) Flow characteristics are__________
a) the same pressure is applied to each actuator.
b) the flow is split amongst the actuators.
Hydraulic fluids that have a low VI number:
have wide viscosity changes with temperature.
The oil characteristic that has the most significant effect on the oil’s lubricating
ability is:
viscosity.
Two (2) conditions that indicate that an oil is excessively oxidized are:
a) the oil will have a burnt odour.
b) the oil will have a watery feel.
State the two conditions that a hydraulic fluid must meet in order to be classified as biodegradable
a) 70 - 80% of the base fluid must be able to be broken down by micro-organisms.
b) The fluid must not harm living organisms.
Why is it a common service procedure to replace the hydraulic filter on a new piece
of machinery after about 100 hours of operation?
To remove built-in contamination from the system.
List four (4) entry points of ingressed contamination.
a) reservoir air breathers
b) pump inlet leakage
c) cylinder seals
d) unclean maintenance procedures.
A rapid total disabling of a system or component is known as an:
catastrophic failure.
