Ramsay Test Ramsay Hydraulics & Pneumatics 6

Question 1

A hydraulic intensifier has a large input piston with an area of 20 in² and a small output piston with an area of 4 in². If 500 psi is applied to the large piston, what output pressure will the small piston generate?

Accepted Answer

2,500 psi

Answer

A hydraulic intensifier multiplies pressure by the ratio of the input area to the output area. P_out = P_in × (A_large / A_small) = 500 × (20 / 4) = 500 × 5 = 2,500 psi. The trade-off is that flow rate is reduced by the same ratio.

Question 2

A hydraulic system suddenly develops a rattling noise and the pump begins eroding internally. Operating temperature is normal and fluid level is adequate. What is the MOST likely root cause?

Accepted Answer

Suction line restriction causing cavitation at the pump inlet

Answer

Cavitation occurs when inlet (suction) pressure falls below the fluid's vapor pressure, typically due to a restricted or undersized suction line, a clogged inlet strainer, or fluid that is too cold and viscous. Vapor bubbles form and then violently implode, causing the characteristic rattling noise and rapid erosion of pump internals. High back-pressure, relief valve setting, and check valve wear do not cause cavitation.

Question 3

A bladder-type hydraulic accumulator is pre-charged with nitrogen to 1,000 psi. System maximum pressure is 3,000 psi and minimum working pressure is 1,500 psi. At what system pressure will the accumulator STOP delivering fluid to the circuit?

Accepted Answer

1,000 psi

Answer

An accumulator delivers stored fluid as long as system pressure is higher than the gas pre-charge pressure. Once system pressure drops to the pre-charge level (1,000 psi), the bladder or diaphragm is fully expanded and no more fluid can be expelled — the accumulator is empty. It stops delivering at pre-charge pressure, not at the minimum working pressure.

Question 4

A counterbalance valve is installed in the rod-side line of a hydraulic cylinder supporting a heavy vertical load. If the upstream supply hose ruptures during a hold cycle, what will the counterbalance valve do?

Accepted Answer

Block rod-side flow and prevent the load from free-falling

Answer

A counterbalance valve maintains a set back-pressure on the rod side that exceeds the load-induced pressure. If the upstream supply line ruptures, pressure at the valve's pilot port drops to zero, so the valve snaps shut and blocks rod-side flow — preventing the load from free-falling. It will only open (in the controlled direction) when positive pilot pressure from the cap-side supply exceeds its set point.

Question 5

A pneumatic venturi vacuum generator uses 80 psi shop air flowing through a converging nozzle. Which statement CORRECTLY describes conditions at the throat of the venturi?

Accepted Answer

Velocity increases and static pressure decreases, generating a partial vacuum

Answer

By Bernoulli's principle, in a flowing fluid total energy is conserved. At the venturi throat, the flow area is smallest, so air velocity must increase to maintain continuity. As kinetic energy (velocity) increases, static pressure energy must decrease — dropping below atmospheric pressure and creating a vacuum at the side port. This is the operating principle of ejectors and vacuum cups in pneumatic systems.

Ramsay Test Practice Test

Ramsay Test Practice Test

Ramsay Test Ramsay Hydraulics & Pneumatics 6