Lesson 7: Switches, Seals, and Components Flashcards
What the 4 types of Hydraulic switches?
Pressure
thermal
position
limit
What is the purpose of a pressure switch?
close circuit for caution light
enable/disable backup pump operation
What are the types of pressure switches?
Piston
Diaphragm
Differential Pressure
How does a piston type switch work?
hydraulic pressure forces a piston against a spring to open micro switch
How does a diaphragm switch work?
similar to piston type but uses a diaphragm
This type of switch uses a integral diaphragm to compare 2 different sources which will result in a CLOSED micro switch
Differential pressure switch
What does a pressure transmitter do?
indicates pressure to the flight deck
What is the purpose of a thermal switch?
enable/disable pump operation
caution light when temp exceeded
temp indication
Purpose of a position switch
provides position on an actuator or flight control
What are the types of POSITION switches?
Micro switch rotary potentiometer lvdt/rvdt proximity sensor
All flight control indications originate from what?
Position switches
Purpose of limit switches?
stops an actuator at the LIMIT of its movement
Autopilot
horizontal stab
flap/slat
use what switch?
LIMIT
This component smooths out pulsations in the flow
Damper
What are the 2 types of dampers?
piston and vane
Piston dampers are used on what
flight controls
This component is commonly used to cool hydraulic fluid and case drain fluid
heat excahnger
Purpose of hydraulic seals?
minimize leakage and loss of pressure
reduce wear
prevent contamination
2 types of seals?
Packing and gasket
This type of seal is used for when a lot of movement exists
packing
this type of seal is used when no movement exists
gasket
what side of the shape is on the high pressure side?
inside of shape
What is the most common seal used on the aircraft?
O Rings
What does the colour code of the o ring identify?
fluid type
When do we use Back up rings?
when system pressure is greater than 1500 psi
2 types of back up rings?
Leather and teflon
MOst effective way to know youre using the right o ring?
Part Number
you mus always lubricate the o ring with?
the fluid being used
What are the types of hydraulic back up supply sources?
EMP Hydraulic Motor (PTU/PDU) ATM RAT Accumulator/air bottle
Purpose of Electric Motor Pump?
electricity to drive hydraulic pump
ac/dc
primary pump on small airc
backup for large
Purpose of Hydraulic motor?
hydraulic system pressure used to operate hydraulic motor = turn drive shaft
This component one system is used to pressurize another system, without a transfer of fluid,
PTU
What are PDUs used for?
flap/slat
horizontal stab
drive train
Purpose of air turbine motor?`
drive hydraulic pump using pneumatic system
This backup is your last hope
the RAT
this backup is used for brakes
accumulator/ air bottle