Mixed Deck — All 433A Topics Flashcards

What does the designation 6205-2RS on a bearing indicate?

Answer: A deep groove ball bearing with a 25 mm bore and two rubber seals

The 6205-2RS designation indicates a 6200-series deep groove ball bearing (62), with a 25 mm bore (05 × 5 = 25), and two rubber contact seals (2RS).

What is an air-over-oil system?

Answer: A system that uses compressed air to pressurize a closed oil circuit, providing smooth hydraulic-like cylinder control with pneumatic power

An air-over-oil system uses compressed air acting on top of oil in sealed tanks to push oil through a closed circuit to hydraulic cylinders. This combines the advantages of pneumatic power (simple, clean) with hydraulic smoothness and rigidity.

What is the function of a hydraulic relief valve?

Answer: To protect the system from excessive pressure by diverting flow back to the reservoir

A relief valve is a pressure-limiting safety device that opens when system pressure exceeds its set point, diverting excess flow back to the reservoir to prevent damage to pumps, cylinders, motors, and other system components.

Which factor most directly affects the L10 life rating of a rolling element bearing?

Answer: Applied load relative to the dynamic load rating

The L10 bearing life is calculated based on the ratio of the bearing's dynamic load rating (C) to the applied equivalent load (P). Life varies with the cube of this ratio for ball bearings and the 10/3 power for roller bearings.

What is the primary purpose of attaching a tagline to a suspended load?

Answer: To control the load's rotation and prevent uncontrolled swinging

A tagline allows workers to guide and stabilise a suspended load from a safe distance without being in the load's fall zone.

What condition is indicated by a blue discoloration on a bearing race?

Answer: Overheating has occurred

Blue or straw-colored discoloration on bearing races indicates that the bearing has been subjected to excessive heat, typically above 200°C. This overheating compromises the bearing's hardness and load capacity.

Why should alignment be rechecked after the final bolt torque?

Answer: Because torquing bolts can shift the machine position or reveal soft foot conditions

Final bolt torquing can cause small but significant shifts in machine position due to uneven clamping forces, soft foot effects, or dowel pins engaging. A final alignment check confirms the machine is still within tolerance.

What is the function of a load cell when used in a rigging operation?

Answer: To measure and display the actual tension force in the rigging during the lift

A load cell is an electronic force-measuring device inserted into the rigging that provides a real-time readout of the actual load being lifted.

In a planetary gear system, what is the function of the ring gear?

Answer: It meshes internally with the planet gears and forms the outer boundary of the gear set

The ring gear (annulus) is the outermost gear in a planetary set with internal teeth that mesh with the planet gears. It can serve as input, output, or a fixed reaction member depending on the configuration.

When grouting a baseplate, why is it important to achieve full contact between the grout and the underside of the baseplate?

Answer: To provide a solid, void-free support that evenly distributes loads and prevents vibration

Full grout contact ensures uniform load distribution from the machine through the baseplate to the foundation, prevents flexing and vibration, and maintains long-term alignment stability. Voids under the baseplate cause uneven support and alignment problems.

What instrument is commonly used to check the flatness of a large baseplate or sole plate?

Answer: Precision machinist level and straightedge

A precision machinist level placed on a straightedge spanning the baseplate surface is the standard method for checking flatness and level of large baseplates and sole plates during installation.

When performing a rough alignment using a straightedge and feeler gauges, what accuracy can typically be achieved?

Answer: Within 0.005 to 0.010 inch

Straightedge and feeler gauge methods can typically achieve rough alignment accuracy of 0.005 to 0.010 inches. This serves as a good starting point before using dial indicators or laser alignment for precision corrections.

When installing a press-fit bearing on a shaft, what is the recommended heating temperature for the bearing?

Answer: Up to 120°C (250°F)

Bearings should be heated to a maximum of approximately 120°C (250°F) for installation. Exceeding this temperature can alter the metallurgical properties of the bearing steel and damage seals or shields.

What is the function of a head pulley lagging?

Answer: To increase the friction coefficient between the belt and pulley by applying a rubber or ceramic surface to the pulley shell

Pulley lagging is a rubber, ceramic, or urethane coating applied to the pulley shell surface to increase the coefficient of friction between the belt and the pulley. This improves drive traction, reduces belt slip, and sheds water that would otherwise reduce grip.

What is the purpose of a hydraulic accumulator?

Answer: To store pressurized fluid to supplement pump flow, absorb shocks, or maintain pressure

A hydraulic accumulator stores energy in the form of pressurized hydraulic fluid. It can supplement pump flow during peak demands, absorb pressure spikes and shocks, and maintain system pressure when the pump is off.

Why should thread sealant tape (PTFE tape) be applied carefully to pneumatic fittings?

Answer: Because loose tape fragments can break off and enter the system, blocking orifices and damaging valve seats

PTFE tape must be applied neatly, starting 1-2 threads back from the end, wrapped in the correct direction, and trimmed cleanly. Loose strands can shear off during assembly and enter the air system, blocking small orifices in valves and instruments.

Why must hydraulic hose assemblies be replaced if the outer cover shows exposed wire braid?

Answer: Exposed braid means the hose has suffered external damage compromising its burst strength and allowing moisture to corrode the reinforcement

Exposed wire braid indicates that the outer protective cover has been worn through or cut, compromising the hose's rated burst strength. Moisture penetrating to the braid causes corrosion, further weakening the hose and risking catastrophic failure.

When using an optical alignment instrument (jig transit), what does the crosshair target represent?

Answer: A fixed reference point representing the true centerline of the bore or surface being aligned

The crosshair target is positioned at the center of a bore or on a reference surface to represent the true centerline. The jig transit telescope then sights on multiple targets to verify that all reference points are in proper alignment.

What is a reciprocating compressor and where is it commonly used?

Answer: A compressor using pistons driven by a crankshaft to compress gas in cylinders, commonly used for high-pressure applications

A reciprocating compressor uses pistons driven by a crankshaft to compress gas in cylinders, similar to an internal combustion engine. It is commonly used in high-pressure applications including industrial air supply, natural gas processing, and refrigeration.

What is the correct procedure for tensioning a screw conveyor that has stopped due to material jamming?

Answer: Lock out the drive, remove the access covers, clear the jammed material manually, check for damage, and restart empty before resuming operation

A jammed screw conveyor must be locked out/tagged out first. Access covers are removed to manually clear the jammed material, inspect the screw flights, trough, and bearings for damage, then the conveyor is restarted empty and gradually brought back to normal loading.