Which factor is least likely to affect the speed of a hydraulic actuator?

Which factor is least likely to affect the speed of a hydraulic actuator?

• A. Piston diameter
• B. How fast fluid can be moved into and out of the cylinder
• C. Fluid viscosity
• D. Friction in seals

Answer: (A)

Actuator speed is determined by how quickly hydraulic fluid can be moved into and out of the cylinder while overcoming system resistance. In practice, the primary lever for changing speed is the flow rate the system can deliver, and the resistances the fluid encounters. Fluid viscosity and friction in seals directly affect how easily fluid flows and how much pressure is lost, so they directly influence speed. How fast fluid can be moved into and out of the cylinder is the most direct control on speed, since faster filling and venting makes the piston move quicker. The piston diameter mainly sets the force the cylinder can produce (F = P × A) and the load it can handle, rather than dictating how fast the piston travels under the same flow conditions, so it is least likely to affect speed.

Actuator speed is determined by how quickly hydraulic fluid can be moved into and out of the cylinder while overcoming system resistance. In practice, the primary lever for changing speed is the flow rate the system can deliver, and the resistances the fluid encounters. Fluid viscosity and friction in seals directly affect how easily fluid flows and how much pressure is lost, so they directly influence speed. How fast fluid can be moved into and out of the cylinder is the most direct control on speed, since faster filling and venting makes the piston move quicker. The piston diameter mainly sets the force the cylinder can produce (F = P × A) and the load it can handle, rather than dictating how fast the piston travels under the same flow conditions, so it is least likely to affect speed.