342 Flashcards
The most common cause of failure in jaw clutches is
Jaw breakage
V-belt sheaves, shafts, and gears can all be used as
Takeoff members
Localized wear on clutch friction surfaces often indicates
Misalignment
Frequent slippage of a brake or clutch is usually an indication of
Overloading
Chatter is usually caused by
Lose or faulty actuating devices
Friction clutches use one or more discs to
Transmit torque to the load
Rapid wear between the friction surfaces by an electric brake or clutch is usually the result of
Overheating
When the slip speed of a clutch drops to zero, the maximum torque the clutch can exert
Increases
The capacity of a clutch to dissipate heat depends on its size and
Armature speed
If a brake or clutch faits to engage property, the first thing to check is the
Voltage supply on its field coil
At ___ output speed, the flanges on the input shaft of an adjustable speed drive are ___
Maximum; closest together
The best protection against unwanted heat in an enclosed drive is a(n)
Steel baffle
When test-running an adjustable-speed drive under no load conditions, it is necessary to operate the drive
Through its full speed range
If you find ridges in a drive’s sheave flanges on an adjustable speed drive, you should
Sand or polish the ridges right away
In an enclosed drive, high temperatures usually result from (a)
Overloading the shaft bearings
The amount of slip between a turbine and its impellor is normally a difference of ___ to ___ percent at full load
3 to 5
A condition called a “stall load” can occur in a fluid coupling when the impeller ___ and the turbine ____
Rotates; does not rotate
Overheating in a flud coupling is usually caused by
Too much slip
A polyphase torque converter has ___ stators that ____
Two or more; rotate
If you find seals that are hard and cracked when you are inspecting a coupling. you should
Replace them
An enclosed gear drive’s thermal capacity is usually expressed in
Horsepower
When you need to change the speed of a load shaft you should select a drive with (a) (an)
Adjustable speed belt
The major cause of drive failure is
Improper lubrication
If an overload occurs in a drive system that is equipped with a spring-operated overload device
the
Sprocket will slip
When test running a drive pror to placing it in service, you should run the drive under no-load conditions for
20 to 30 minutes
