Glossary

Magnetic Lock - A motion impediment produced by an unshielded magnetic field attracting and accumulating ferromagnetic particles that induce surface lockup.

Manual Override - A means of manually operating an automatic control.

Micron (or Micrometer) - One thousandth part of one mm, 0.0000394-in., or one-millionth of a meter. A common unit used when specifying filters, sieves and screens.

Modulus, Rubber (or Elastomer) - The stress level at a predetermined elongation, usually reported at 100%. It is a good indicator of compound toughness and at a given hardness, high modulus generally means good anti-extrusion and dynamic characteristics.

Motor, Fixed-displacement - A rotary motor in which the displacement per revolution is not adjustable.

Motor, Rotary - A motor capable of continuous rotary motion and producing an output torque proportional to the displacement per revolution and the pressure drop between intake and discharge ports.

Motor, Variable-displacement - A rotary motor in which the displacement per revolution is adjustable.

Natural Frequency - The frequency of the cycling motion of an undamped second-order component. For a transient-response curve, the frequency of cycling which the deviation would have if the response were undamped. Also the frequency at which an object would vibrate at zero damping. On a Bode Plot of a second-order system, it is the frequency where the extension of the final slope of the response curve intersects the 0-db line of the amplitude ratio.

Neutralization Number - A measure of the acidity of a fluid. It is defined as the milligrams of potassium hydroxide required to neutralize the acidity in one gram of fluid.

Newtonian Fluid - A liquid in which viscosity is independent of the shear rate of the fluid.

Nomograph - A chart on which a straight line can be drawn so as to intersect three scales in values that satisfy an equation or a given set of conditions.

Non-return Valve - A valve which normally allows flow in one direction only.