Passage: A machined or cored fluid conducting path which lies within or passes through a component.

Parallel: Refers to a data communication format wherein many signal lines are used to communicate more than one piece of data at the same time.

Peak torque: The maximum torque a brushless motor can deliver for short periods of time Operating PacTorq motors above value can cause demagnetization of the rare eart magnets. This is an irreversible effect that will alter the motor characteristics and degrade performance. This is also known as peak current. Not to be confused with system peak torque, which is often determined by amplifier peak current limitations, where peak current is typically two times continuous current.

Phase Angle: The angle at which the steady state input signal to a system leads the output signal.

Phase Margin: The difference between 180⁰ and the phase angle of a system at its crossover frequency.

Pilot Valve: An auxiliary valve used to control the operation of another valve. The controlling stage of a two stage rod.

Piston: A cylindrically shaped part which fits within a cylinder and transmits or receives motion by means of a connecting rod.

PLC: Programmable logic controller, a machine controller that activates relays and other I/O units from a stored program. Additional modules support motion control and other functions.

PMC: Programmable motion controller, primarily designed for signal or multi axis motion control with I/O as an auxiliary function.

Poppet: A valve that moves perpendicular to or from its seat.

Poles: Refers to the number of magnetic poles arranged on the rotor of the brushless motor. unlike an AC motor, the number of poles has no direct relationship to the base speed of the motor.

Port: An internal or external terminus of a passage in a component.

Power: Work per unit of time, measured in horsepower (hp) or watts.

Power Factor: Ratio of torque power (KW) to apparent power (kVA)

Power Pack: An integral power supply unit usually containing a pump, reservoir, relief valve and directional control.

Precharge Pressure: The pressure of compressed gas in an accumulator prior to the admission of liquid.

Pressure: Force per unit area, usually expressed in pounds per square inch (psi).

Pressure Line: The line carrying the fluid from the pump outlet to the pressurized port of the actuator.

Pressure Override: The difference between the cracking pressure of a valve and the pressure reached when the valve is passing full flow.

Pressure Reducing Valve: A valve which limits the maximum pressure at its outlet regardless of the inlet pressure.

Pressure Switch: An electric switch operated by fluid pressure.

Proportional Valve: A valve which controls and varies pressure, flow direction, acceleration and deceleration from a remote position. They are adjusted electrically and are actuated by proportional solenoid rather than by a force or torque motor. The output flow is proportional to the input signal. They provide moderately accurate control of hydraulic fluid.

Pole: A frequency at which the transfer function of a system goes to infinity.

Pulse Rate: The frequency of the step pulses applied to a motor driver. The pulse rate multiplied by the resolution of the motor/drive combination (in steps per revolution) yields the rotational speed in revolutions per second.

Pulse Width Modulation: A PWM controller (amplifier) switches DC supply voltage on and off at fixed frequencies. The length of the on/off interval or voltage waveform is variable. Pulse width modulation (PWM), describes a switch mode (as opposed to linear) control technique used in amplifiers and drivers to control motor voltage and current.

PWM: Pulse Width Modulation. A method of controlling the average current in a motors phase windings by varying the on-time (duty cycle) of transistor switches.