Millwright – Hydraulics Exam | 67 Questions with 100% Correct Answers | Updated & Verified, Exams of Hydraulics

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Millwright – Hydraulics Exam | 67 Questions

with 100% Correct Answers | Updated & Verified

What is pressure defined as? ✔✔Force per unit area F=(P)(A) What is the pressure of the Earth's atmosphere at sea level? ✔✔14.7 psi How is power defined? A. The rate or velocity at which power is done B. The rate or velocity at which work is created C. The speed of the velocity in a power system D. The rate or speed at which work is done. ✔✔D. The rate or speed at which work is done. What is a watt? A. watt is one newton lifted 1 m in one second. B. Power unit defined by its work C. Watt is 1 N lifted 1 cm in one second D. One jule per second squared ✔✔A. watt is one newton lifted 1 m in one second. What is one horsepower equal to? ✔✔1 horsepower is equal to 746 Watts or 33000 pounds lifted one foot in one minute.

What is the law of conservation of energy? A. Energy cannot be destroyed, but it may be created from one form to another. B. Energy cannot be destroyed, but it may be converted from one form to another. C. Energy can be destroyed, but cant be converted from one form to another D. Energy cannot be destroyed, but it may be transformed to another form of power ✔✔B. Energy cannot be destroyed, but it may be converted from one form to another. How much does hydraulic fluid compress? A. Hydraulic fluid compresses about 0.5% at 10000 psi. B. Hydraulic fluid compresses about 0.5% at 1000 psi. C. Hydraulic fluid compresses about 0.5% at 1000 kPa. D. Hydraulic fluid compresses about 0.15% at 1000 psi. ✔✔B. Hydraulic fluid compresses about 0.5% at 1000 psi. What is Pascal's Law? A. When pressure is applied to a confined liquid at rest, force is transmitted equally in every direction and always at right angles to the containing surface. B. When pressure is applied to a confined liquid at rest force is transmitted equally in all directions C. The law of pressure D. The law of fluid pressur ✔✔A. When pressure is applied to a confined liquid at rest, force is transmitted equally in every direction and always at right angles to the containing surface. How many cubic inches in one US gallon? A. 231

Describe laminar flow. ✔✔In ideal flow situations the fluid moves in layers, parallel to the walls of the conductor. The fluid at the outer walls of the conductor moves more slowly than the fluid in the center of the conductor. Describe turbulent flow. ✔✔When smooth flow is disrupted, the fluid particles move in a random pattern rather than parallel to the direction of flow. What is friction? ✔✔A. Friction is the resistance to relative motion between two bodies. B. Friction is the passing of objects and their opposing force C. Acting force on a body D. Opposite of smooth What are the main causes of excessive friction in hydraulic lines? ✔✔Excessive length of lines Excessive velocity because the lines are too small Excessive number of bends or fittings, or unsuitable bends or fittings Sustained flow at high pressure What is Bernoulli's principle? ✔✔Bernoulli's principle states that if the flow rate is consistent, the sum of the kinetic energy and potential energy at various points in the system is constant. Therefore, whenever the velocity of a fluid increases, the pressure decreases. What are hydraulic actuators? ✔✔A. components of hydraulic systems that convert hydraulic energy into mechanical energy. B. components of hydraulic systems that calculate hydraulic energy and mechanical energy.

C. Valves D. Electric valves How are cylinders sized? A. They are sized by shaft diameter, piston rod diameter and stroke length. B. They are sized by piston diameter, piston rod diameter and stroke length. C. They are sized by piston radius, piston rod radius and stroke length. D. They are sized by piston diameter, piston rod diameter and pressure rating ✔✔B. They are sized by piston diameter, piston rod diameter and stroke length. What is a tandem cylinder? ✔✔Tandem cylinders have two Pistons attached to one rod this design allows for higher forces at the rod end without an increase in fluid pressure or cylinder diameter. What is the definition of displacement? ✔✔Displacement is the amount of liquid handled in one rotation of the motor. It is usually expressed in cubic centimeters per revolution or cubic inches per revolution. What is torque effect? ✔✔Torque output is a function of the system pressure and the motor displacement. It is expressed in newton meters or inch pounds. How are DCV valves classified? ✔✔Directional control valves are classified by the number of flow passages, followed by the number of distinct positions. They are also classified by spool type (sliding or rotary), nominal size, maximum allowable pressure, port connections, either threaded national pipe taper or national pipe straight, flanged or flat face.

B. Heat, contamination, and axial force C. Lube failure, contamination, and leakage. D. Heat, friction, and leakage. What is 1 micron? ✔✔1 micron equals one millionth of a meter, or 39 millionths of an inch. The smallest particle that can be seen with 20-20 vision is about 40 microns. What is the difference between a nominal filter and an absolute filter? ✔✔A nominal filter filters most particles, and absolute will stop all particles. What is the purpose of a baffle plate in a hydraulic reservoir? ✔✔The baffle plate prevents a direct flow of fluid from the return line to the suction line. Slowing the oil movement allows trapped air to escape and foreign material to settle on the bottom. It also allows the fluid to cool before passing back through the pump. What is the purpose of an accumulator? ✔✔A. To trap foreign matter for draining B. Accumulators store fluid under pressure for future use as a source of potential energy. They also absorb shock waves or dampen pulsations and maintain constant pressure in the system C. Accumulators force fluid under pressure for future use as a source of potential energy. They also absorb shock waves or dampen pulsations and maintain constant pressure in the system. D. Accumulators store liquid under pressure for future use as a source of kinetic energy. They also absorb shock waves or dampen pulsations and maintain constant pressure in the system. What are three classifications of accumulators?

A. Weight loaded, spring loaded, and pneumatic or gas charged. ✔✔A. Weight loaded, spring loaded, and pneumatic or gas charged. B. Weight loaded, spring loaded, and mechanical C. Mechanical, spring loaded and thermodynamic D. Thermodynamic, thermostatic and mechanical What is viscosity index? ✔✔It's change in viscosity over a given temperature range. What is pour point? ✔✔The lowest temperature at which oil will flow. How should you store hydraulic fluid in a barrel? ✔✔Hydraulic fluid in barrels should be stored on their side, keeping water and contaminants from collecting around the bung. How is tubing measured? ✔✔Tubing sizes are taken from the outside diameter, the nominal dimensions are given in fractions of an inch or dash numbers. The dash number represents the outside diameter in sixteenths of an inch. For example, a dash number 8 indicates an OD of 8/16 or 1/2 an inch. What are the two most common flare angles for tubing? C. 45 deg. (SAE) or 37 deg. (JIC) ✔✔A. 55 deg. (SAE) or 37 deg. (JIC) B. 45 deg. (SAE) or 45 deg. (JIC) C. 45 deg. (SAE) or 37 deg. (JIC) D. 90 deg. (SAE) or 57 deg. (JIC) What is the maximum bend radius for tubing? ✔✔Generally, three to four times the tube OD.

pressure of available to each motor is proportional to load on each. In a parallel circuit, if the load on either motor is the same, then they rotate at half the speed of a single motor. What are the causes of cavitation in a pump? ✔✔clogged strainer dirty filter obstruction in the inlet line fluid viscosity too high operating temperature too low excessive pump speed what are the causes of air in the fluid? ✔✔fluid level too low leaky or damaged inlet line damaged shaft seals What are 3 main causes of pump damage? ✔✔worn out due to extended use coupling misalignment cavitation What are causes of excessive load on a pump or motor? ✔✔relief or unloading valve set too high worn bearing mechanical binding pump coupling misaligned motor coupling misaligned What would cause a rise in fluid temperature? ✔✔system pressure too high

dirty fluid low fluid level incorrect fluid viscosity faulty cooling system What would cause erratic pressure? ✔✔air in the fluid worn relief valve contamination in the fluid defective accumulator loss of charge in accumulator What are common valve problems? ✔✔spool sticking due to foreign material a broken spring or detents have come out of position spool not shifting due to burned-out solenoid excessive leakage due to defective O-rings, scored spool or valve body What is varnishing? ✔✔A coating of oxidized fluid deposited on internal surfaces of components as a result of heat. What is pump slippage? ✔✔Internal leaking of fluid from the pressure side to the suction side of a pump. A hot spot on the side of a cylinder is often a symptom of what? ✔✔blow-by

what is the SI unit for kinematic viscosity? ✔✔mm squared/sec what is the minimum schedule pipe used for hydraulic purposes? ✔✔schedule 40 what does jic stand for? ✔✔joint Industrial Council