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Specifications and tests

AC : Alternating current; electric current that continually reverses direction at a fixed frequency (see VAC).

ACTUATION FORCE : (Operating Force) : The force required to change the actuator of a switch from one position to another. Torque for rotary products.

ANTISTATIC : An antistatic device will withstand a specified potential without conducting between the actuator and any conducting element. Usually the terminals or bushing. Unit of measure : typical value 8-20 kilovolts DC.

ARCING : The flow of electric current between switch contacts during opening or closing of the contacts. This current flow can be damaging to the contacts of a switch.

BOUNCE : The repeated rebounding of the moveable contact during the transfer from one throw to the next.

CAPACITIVE LOAD : A load in which the initial current on making (closing) of the contacts is higher than the steady state current. Current leads voltage in capacitive loads. See Resistive Load, Inductive Load, Power Factor, Inrush.

CARRYING CURRENT : The maximum current that can be passed through the already closed contacts of a switch.Contrast with "Contact Rating".

CONTACT RATING (Switching rating) : The capacity to switch (connect or interrupt) an electrical load. Load characteristic (resistive, inductive, capacitive, power factor). Contrast with non-switching rating.

CONTACT RESISTANCE
: The resistance across the two closed contacts : contact interface and terminals.

CREEPAGE : The unwanted flow of electrical current from one conductive part to another.

CYCLE : The complete sequence of indexing through all successive switch positions and returning to the original position.

DC : Direct Current : electric current that flows only in one direction (see VDC).

DIELECTRIC STRENGTH : The ability of an insulating material to withstand a voltage without arcing across its surface. The standard voltage that can be applied between two open terminals or between a terminal and ground without causing short. Most often applied to insulator between switch terminals and metal exposed to operator of the switch. Also known as Dielecric Withstanding Voltage, DWV, Leakage resistance, Breakdown Voltage.

DRY CIRCUIT
: An application in which power level do not cause arcing melting, or softening of the contacts . Typically requires gold plated contacts for reliable switch operation. At such low levels, and since no arc occurs, silver contacts would not be selfcleaned and would be less reliable. Typical Definition : for ex. 0.4VA max. 20 V DC or peak AC max. Also known as "Low Energy", "Logic Level", TTL.

DWV : Dielectric Withstanding Voltage. See Dielectric Strength.

ELECTRICAL LIFE : The number of operations at a given electrical load that does not result in a degradation of any electrical or mechanical parameter beyond the standard set by the applicable end-of-life criteria.

END OF LIFE CRITERIA : Those specifications that a switch must meet at the end of its specified electrical life. Typically contact resistance and/or heat rise of contacts at full rated load at end of life.

ESD : Electrostatic discharge.

HEAT RISE : An indirect measurement of contact resistance used by rating agencies. The temperature rise over ambient of a contact set carrying a prescribed current is measured to determine whether it falls within safe limits.

INDUCTIVE LOAD : A load in which the initial current on making (closing) of the contacts is lower than steady state and rises slowly. On breaking (opening) of the contacts, the current is greater than steady state. The stored energy of the inductor provokes a long and severe arcing time. Current lags voltage in inductive loads. Motors are the most common inductive load. Inductive loads are the most troublesome of circuit conditions. See Resistive Load. Capacitive Load.

INRUSH : The initial transitory high-level of current at contact closing (making). A characteristic of capacitive and some resistive loads. The inrush currents can be large and long enough to cause severe degradation of the contacts. See Resistive Load. Capacitive Load. Power Factor.

INSULATION RESISTANCE : The electrical resistance between two normally insulated parts measured at a specified DC voltage.

IP : An industrial specification (Part of the IEC529 standard) used worldwide to indicate the degree of protection provided by components against accidental contact, penetration of solids or liquids into or through the component. See NEMA.

LAMP LOAD (Tungsten) : A load characterised by a high inrush current at make (approximately 10 to 16 times the steady state).

LEAKAGE RESISTANCE : Dielectric strength

LIFE : See Electrical life, Mechanical Life.

LOGIC LEVEL : Refers to power levels typical of solid state electronic circuits (TTL, CMOS, etc.). Levels at which no arcing, melting or softening of the contacts occur. Typically require gold contacts for reliability since no arcing occurs to self clean the contacts. See Dry circuit. Also referred to as low energy

LOW ENERGY : See Dry circuit.

MECHANICAL LIFE : The number of operations of a switch without electrical load that does not result in a degradation of parameters beyond the standard set by the applicable end-of-life criteria.

MOISTURE PROOF : Sealed switch will withstand high humidity and limited exterior environment such as rain.

NON-SWITCHING RATING
: The power carring capacity of a switch after contact closure and end of contact bounce. Typically far higher than the contact rating (switching rating) of a switch.

OPERATING FORCE : See Actuation Force.

OPERATING TEMPERATURE : The range of temperature within which the device may be used.

POWER FACTOR (PF) : A measure of the inductive or capacitive character of an electrical load.

RATING : See contact rating

RESISTIVE LOAD : Current and voltage are in steady state on opening or closing the switch. See capacitive load, Inductive load, Power factor, Inrush.

STORAGE TEMPERATURE : The range of temperature within which the device may be stored. Typically this is a wider range than operating temperature.

TACTILE FEEL (FEEDBACK) : The switching action felt by the operator of the switch (same as click action or positive action). Audible or "feel" snap or click that indicates contact movements.

TRAVEL : The total distance the actuator can move. See Pretravel, Overtravel.

VAC : Voltage, alternating current (see AC)

VDC
: Voltage, direct current (see DC)