Jan18th Flashcards
What are 4 examples of hydraulic contamination
Heat
Dust/dirt
Moisture
Cavitation - air bubbles in fluid
What are 4 possible outcomes of cavitation
Spongy action
Chattering
Pump noise
Pump to stop
What are four possible outcomes of overheating hydraulics
Heat can cause fluid to break down
Hardens the seals
Causes leaks
Reduces power
What are some things that can happen to your hydraulics during cold weather operations
Oil gets more viscous which causes functions to slow and movements can become jerky. Multiple function operations can become difficult
What are some tips for cold weather operations
Always warm up hydraulic system
Ramp up the warm up exercises
Watch for leaks
Be sure to check oil levels and not overfill
What is an IC engine
The internal combustion engine converts chemical energy into useful mechanical energy by burning the fuel. Chemical energy is released when the fuel air mixture is ignited by a spark in the combustion chamber
What has a higher combustion ratio, diesel or gas engine ?
Diesel 17:1
Gas 8:1
The highly compressed air gets superheated which causes combustion to happen In a Diesel engine
What are the two types of engines
Four stroke
Two stroke
What are the four strokes in one cycle of a four stroke cycle engine
- Intake stroke
- Compression stroke
- Power stroke
- Exhaust stroke
In a two stroke engine what happens in the first and second stroke to complete on cycle
First stroke -intake and compression
Second stroke - power and exhaust
What are the components of an air system
Air filters
Intake manifold
Supercharger
Turbo charger
What are two starting aids of Diesel engines
Glow plugs Starting fluids (gaseous mixture)
Define a glow plug and it’s role
A small electrical device that heats the combustion chamber
Acts as a pilot light to ignite the main mixture
What is starting fluid
An ether based mixture which is sprayed into the intake system
The fluid will ignite at a much lower temp which will aid in cold starting
What are the two types of cooling systems
Liquid cooled
Air cooled
What is the most common type of liquid cooling system
Independent self contained type
What are the 9 components of a liquid cooling system
Pump Radiator Radiator cap Thermostat Fan Filter Belts Hoses Gauges
Define a radiator
A heat exchanger which reduces the temperature of engine coolant
What does a pump In a liquid cooling system do
Circulates the coolant through the engine
What does a rad cap do
Controls the pressure in the cooling system
What does the thermostat do
Controls the amount/flow of coolant to the radiator
What are the hoses in a liquid cooling system made from
Generally made from synthetic rubber that can resist high temps oils and chemicals
What is the most common type of belt found on cooling systems
The v belt
Is the fan in a liquid cooling system suction or blower type
It can be either
What external device could you use to monitor your coolant
Specific gravity tester
What is the most common oil system found in vehicles today
A full flow system
Where might you find a by pass filter system
In older applications
What is the advantage of a full flow and bypass system
Will allow longer oil change intervals
How does a dual flow system differ from full flow and bypass
They are designed with both filters in the same canister
What are the two types of lubrication systems
Oil system internal force feed
Splash feed oil system - mainly found on 2 stroke engines
What are the six parts of an oil system
Oil pump Oil filter Oil sump/pan Oil lines/passages Oil cooler Monitoring devices
What are five monitoring devices of an oil system
Pressure gauge Oil temp stick Dipstick Warning devices Sending unit
What do the numbers before and after the W indicate in muti grade oil
Numbers before the W indicate viscosity at cold temperatures
Numbers after the W indicate viscosity at hot temperatures
What are the six components of the fuel system
Tank/reservoir Filter Pump Metering system- injectors / carburetor Monitoring devices Fuel lines
What is the purpose of diesel fuel injection
To provide a metered amount of atomized fuel into the heated air of the combustion chamber
What are the components/roles of the chassis
The main frame
Acts as the chassis for all major components of the carrier and the crane
Provides a stable working platform for the crane
What is the purpose of a clutch
To connect or disconnect power from the engine. A clutch in good order should allow a certain amount of controlled slippage but most not slip when fully engaged
What are the components of a overrun/sprag clutch and what does it do
It free wheels in one direction and locks in the other
Outer race
Sprag
Inner race
What does a torque converter do and what principle does it work on
Acts as a fluid clutch to automatically engage and disengage power from the engine to the automatic transmission
Works on the fluid coupling principle
Name three types of wheels
Spoke wheel/Dayton wheel
Disc wheel/bud wheel
Split rim/multi piece wheel
Where would you see wear on an overinflated tire and on an under inflated tire
Overinflated wear in the middle
Underinflated wear on the outsides
What three things will you need to inflate a heavy mobile crane tire
Tire cage
Clamp on air chuck
PSI gauge
Mobile crane automatic transmissions are large and heavy duty. Most are found with how many speeds
8-10 and a crawler gear that can only be engaged when at a complete stop
What is the purpose of the components that make up a drive line
Connect the transmission to the drive axels
What are most drive shafts made from, what do they do
Most drive shafts are made from high tensile steel tube with a yoke on one end and a male stub spine welded to the other end. The drive shaft connects the transmission to the rear axels to form a drive line
What are the components that make up the differentials and what do they do
Diff case
Side gear
Spider gear
Ring gear
Allows the wheels to turn at different speeds
If you had a big gear driving a small gear would you have more speed less torque ?
Yes
Small gear driving big gear gives less speed more torque
What is the purpose and components of planetary hubs
Planetary hubs are assemblies connected directly to the driving wheels, they provide a final gear reduction
Ring gear
Sun gear
Planet pinions
What are the two most common types of suspension on mobile cranes
Solid walking beam suspension
Hydraulic suspension
What is another type of suspension sometimes found on boom trucks
Air ride suspension
All modern crane carriers are equipped with air brakes. Name the three main styles
Drum brakes with s-cam actuators -automatic or manual slack adjusters Drum brakes using wedge actuators - wedge actuators have no manual adjustment Disc brake
What is caging
A method of releasing brakes in an emergency situation
Are all steering systems in truck cranes hydraulically assisted ?
Yes
What is the difference in a 12/24 voltage system compared to a 12 or a 24
12/24 volt system gives 24 volts to the starting system and 12 volts to the rest of the crane
A series parallel switch is used to supply the starter with the 24 volts
What are the four main electrical systems
Starting
Charging
Ignition
Monitoring
What are six components of the electrical system
Ignition switch Alternator Starter motor batteries Wiring Fuses/breakers
What is another term for fuses/breakers
Overload protection devices
What will double when you wire batteries in parallel and what is the advantage
The amps will double
You will get a longer run time
If you wire batteries in series what will double
Voltage will double
What would you use to test a battery
Volt meter or load tester
What would you use an ammeter for
To indicate the amount of current flowing into or(charging) or out of(discharging) a charging circuit
What are the four steps to boosting a battery
Hook up positive terminal of dead battery
Hook up positive terminal to starting vehicle battery
Hook up negative terminal to starting vehicle battery
Hook up negative clamp to engine black or frame of dead battery vehicle
What are the six most common manufactures of Diesel engines in cranes
Cat Detroit Cummings Liebherr Mercedes Benz Volvo
What are the three major functions of transmissions automatic or manual
Accept power from the engine
Provide a neutral position so the engine can run free without moving the carrier
Provide a reverse gear
What does the size, type and number of speeds in a manual transmission depend upon
The size and weight of the carrier and the rear axle assembly
What are 8 types of gears and where would you find them
Spur gears (transmissions) Straight bevel gears (industrial equipment/some differentials) Spiral bevel gears (industrial equipment/some differentials) Worm gear set (gear reduction boxes) Hypoid gears (differentials) Planetary gear set (transmissions) Helical gears (transmissions) Herringbone gears (transmissions)
What are two different types of accumulators found on the suspension
Bladder accumulator
Piston accumulator
What are a few things you can perform for battery maintenance
Maintain electrolyte level
Keep all posts and cables clean and tight
Charging a lead acid battery
Two types of hydraulic control
Directional control
Pressure control
