Glossary
Alternating current (AC) is an electric current that repeatedly changes its direction or strength, usually at a certain frequency or range of frequencies (50 or 60 Hertz).
A mechanical, electrical, or hydraulic device, or their combination, used to effect some predetermined linear, rotary, or oscillating movement. An actuator essentially converts hydraulic or air pressure into mechanical force. Basically, there are two types of actuators: uni-directional and bi-directional. In the uni-directional actuator, the piston moves in a single direction as a result of system pressure. In a bi-directional system, the actuator’s piston moves in either direction.
The space between the armature and the stop.
The stable coil-wire temperature with no electrical power to the Solenoid.
The absolute value of magnetic flux determined by the number of copper wire turns in the coil and the magnitude of the current. Permissible temperature rise of the coil limits the magnitude of the power input. Heat makes the coil less efficient because it reduces the ampere turns and hence the flux density and the torque or force output.
The application of electronic protection devices across the Solenoid coils to reduce the arc caused by interrupting the current flow through an inductive device such as a Solenoid.
The ATEX directive consists of two European Union directives describing what equipment and work environment is allowed in an environment with an explosive atmosphere.
The amount of movement the armature travels lengthwise.
The graph of the ratio of flux density to magnetic field intensity. The magnetic field intensity is usually plotted logarithmically.
A plastic spindle or cylinder component on which the magnet wire is wound.
The D-Frame or Box Frame solenoid offers “medium” magnetic efficiency and provides mid-range force/stroke.
The C-Frame or U-Frame solenoid is the most cost effective frame shape but is the least magnetically efficient and provides the lowest force/stroke.
Canadian safety ratings are regulated by the Canadian Electrical Code (CEC), closely following the US-NEC Standards.
The copper windings on the Solenoid that provide an electrical element through which a current is passed to generate a magnetic field. During the winding process, a precision wound coil follows a prescribed pattern in which each turn is laid precisely beside the previous turn. This allows the maximum amount of copper to be wound in the allotted space. A coil with no specific winding pattern is called a random wound coil.
Resistance values are shown in ohms for each solenoid wire AWG for a temperature of 20°C.
The actual temperature of the magnet wire in the coil winding is the combination of ambient coil temperature plus heating due to current flow through the coil.
Plunger face and face of fixed pole piece are matching 60° concave and convex cones.
Solenoid ON continuously without interruption for periods of about 30 minutes or longer. With no OFF time to allow the coil to cool, continuous duty Solenoids must have coils wound to limit the current drain and must be large enough to provide for adequate heat radiation to prevent coil burn-out. A continuous duty Solenoid will be considerably larger than an intermittent design to produce the same force / stroke.
Wattage/Voltage (for any given solenoid, at 76°F (25°C).
The level of protection from gradual destruction of materials, (usually metals), by chemical reaction with its environment. The salt spray test is a standardized test method used to check corrosion resistance of coated samples—testing procedure and testing parameters are standardized under national and international standards, such as ASTM B 117. These standards describe the necessary information to carry out this test, such as temperature, air pressure of the sprayed solution, preparation of the spraying solution, concentration, pH, etc.
Wattage/Voltage (for any given solenoid, at 76°F (25°C).
One complete motion of a solenoid from its resting position to full extension and back.
Tubular or cylindrical solenoids offer “maximum” magnetic efficiency and provides the best force/stroke.
The D-Frame or Box Frame solenoid offers “medium” magnetic efficiency and provides mid-range force/stroke.
Direct current (DC) is the unidirectional flow of electric charge.
The resistance between the coil and the case. Minimum dielectric value is 500 VRMS and ranges up to 1,500 VRMS depending on the solenoid size, type and wire gauge. Dielectric values are shown for each Solenoid in the specifications chart.
Electromechanical Solenoids engineered to offer operational durability in extreme conditions. These environmentally protected Solenoids are designed to block contamination, offer vibration resistance, and provide corrosion protection in challenging environments.
Under normal in-plant ambient conditions, standard designs should perform satisfactorily over expected life. Unusual conditions of airborne contamination may require protective boots to seal off the plunger cavity. Additional protection of exposed surfaces may be required.
A comparison of the time a solenoid is energized to the time it is de-energized, expressed as a percentage: Duty Cycle % = [(ON time) / (ON time + OFF time)] x 100. For a given force / stroke requirement the smaller the duty cycle percentage, the smaller the Solenoid.
Natural effects that cause energy output to be less than energy input. While efficiency losses can be minimized with good design, no system is 100% efficient.
The solenoid is energized when current is supplied to the coil.
Standard Solenoids are designed to meet normal environmental and operating conditions encountered in conventional industrial applications:
Humidity/Water Splash—Coil area is protected and exposed surfaces plated to withstand occasional water splash and normal in-plant ambient humidity conditions. For continuous high-humidity exposure or water immersion, special encapsulated or molded-coil constructions are available. For extreme environmental conditions, hermetically sealed designs may be required.
Sand/Dust/Dirt—Under normal in-plant ambient conditions, standard designs should perform satisfactorily over expected life. Unusual conditions of airborne contamination may require protective boots to seal off the plunger cavity. Additional protection of exposed surfaces may be required.
Temperature—Since Solenoid output force will continue to improve (though current draw will increase) with ambient temperature decrease, operation of standard designs in an ambient temperature as low as –65°F (–53°C) presents no problem. It is when Solenoids will be operated in an ambient environment above 76°F (25°C) that some caution must be taken. If the temperature is significantly above 76°F (25°C), coil burning may occur even if Solenoid is operated at its rated duty cycle and voltage. Special high-temperature coil designs are available.
The plunger face (internal end) and face of the fixed pole piece are flat. A flat face construction should be selected for relatively short strokes or where maximum hold forces are required.
The physical manifestation of a condition existing in a medium or material subjected to a magnetizing influence. The quantity is characterized by the fact that an electromotive force is induced in a conductor surrounding the flux during any time there is a change in flux magnitude. A unit of flux is a Weber which is defined as the amount of flux that, linking an electrical circuit of one turn (one loop of wire), produces in it an electromotive force of one volt as the flux is reduced to zero at a uniform rate in one second.
The load the solenoid is capable of pulling, pushing, or holding at the start of specified stroke when energized under a specific set of conditions: of voltage, temperature, and duty cycle. The force rapidly increases as the pull or push stroke length decreases.
The outer shell and main component of the solenoid housing.
FD demands that nothing can change relative to or affect the form, fit or function of the end product.
FP demands that nothing can change relative to the processes used to manufacture the components that go into each product; nothing can be changed involving the assembly process that is employed to manufacture and test the end product.
Electrohydraulic solenoid Coils engineered, certified and approved specifically for use in hazardous environments. Designed with an epoxy-filled encapsulation, these coils offer corrosion protection, are resistant to dust and moisture contamination, and are equipped with an internal temperature sensor that limits surface temperature.
The stable increase in coil wire temperature during Solenoid operation at rated voltage and duty cycle in designed ambient conditions. Standard units are designed for a 274°F (134°C) maximum rise in a constant 76°F (25°C) ambient environment.
A passive component that cools the solenoid by transferring heat to the surrounding air. It is important to consider the size of the heat sink when selecting the Solenoid size and applicable wattage.
Plunger is pulled in, either electrically or by external force, and contacts the opposite pole piece. With power applied, the plunger remains fixed resisting the external pull or push load.
Coil area is protected and exposed surfaces plated to withstand occasional water splash and normal in-plant ambient humidity conditions. For continuous high humidity exposure or water immersion, special encapsulated or molded coil constructions are available. For extreme environmental conditions, hermetically sealed designs may be required.
International Electrotechnical Commission System for certification to standards relating to equipment for use in explosive atmospheres.
A two-digit number established by the International Electro Technical Commission, is used to provide an Ingress Protection rating to a piece of electronic equipment or to an enclosure for electronic equipment.
The protection class after EN60529 are indicated by short symbols that consist of the two code letters IP and a code numeral for the amount of the protection.
Example: IP65 (NEMA 4)
The two digits represent different forms of environmental influence:
• The first digit represents protection against ingress of solid objects.
• The second digit represents protection against ingress of liquids.
The larger the value of each digit, the greater the protection. As an example, a product rated IP54 would be better protected against environmental factors than another similar product rated as IP42.
Solenoid ON for only a short time, usually not more than 2 or 3 minutes, then followed by an OFF time which is normally at least as long as the ON time. This ON time and OFF cycling can be repeated continuously over the total life of the solenoid.
A coil whose individual turns have a prescribed pattern which they must follow during the winding process whereby each turn is laid precisely next to the previous turn. This process allows for the maximum amount of copper in the allotted space. Normally carries a ±5% tolerance on coil resistance.
Standard temperature rated coils use PVC insulated stranded lead wire, UL style 1007 rated for 80°C at 300 volts. They also meet CSA type TR-64, 90°C at 600 volts; and MIL-W-16878/2, 105°C at 1000 volts. High temperature coils use Teflon type E, TFE lead wire and meet MIL-W-16878/4A rated at 200°C at 600 volts.
Motion that takes place in a straight line rather than rotating in place around an axis.
100% copper wire, UL-recognized, single-build insulation rated at 200°C (Class H), meets UL file E-37683 or E-34609. Also meets federal specification J-W-1177/13 or J-W-1177/14. Tubular and Open Frame Solenoids use single-build insulation rated at 130°C. It meets UL file E-34609 or E-37683 and Federal Specification J-W-1177/9.
MSA-FD is specific to the product category and outlines useful and necessary reasons to rework FDs—including obsolescence and government mandates, unexpected cost increases, planned beneficial design changes, and continuous improvements (involving quality, performance and/or cost).
MSA-FP will utilize any manufacturing equipment and process, lean assembly cell, and outside service/material supplier necessary to ensure that the precision and integrity of every component; the form, fit and function of every final assembly will meet and exceed our customer’s technical and commercial expectations.
Electrical safety ratings in the US are governed under the National Electrical Code (NEC). There are two separate classification systems (NEC 500 and NEC 505). The NEC is approved as an American national standard by the American National Standards Institute (ANSI).
Mandatory for Gulf of Mexico Class and Zone Rating. Most international markets require recognition under the International Electrotechnical Committee (IEC) Ex scheme
National Electrical Manufacturers Association Type 4X:
Enclosures constructed for either indoor or outdoor use to provide a degree of protection to personnel against access to hazardous parts; to provide a degree of protection of the equipment inside the enclosure against ingress of solid foreign objects (windblown dust); to provide a degree of protection with respect to harmful effects on the equipment due to the ingress of water (rain, sleet, snow, splashing water, and hose directed water); that provides an additional level of protection against corrosion; and that will be undamaged by the external formation of ice on the enclosure.
The opening in a valve that media, gas or liquid flows.
The ratio of flux density in a given medium to the magnetic field intensity.
The ratio of the flux through any given cross section of a given medium (bounded by equipotential surfaces) to the difference in magnetomotive force between the two surfaces.
The magnetic moving component of a linear solenoid.
Having two oppositely charged poles, one positive and one negative. Polarity determines the direction in which current tends to flow.
The pole or stop is stationary component within the solenoid that attracts the moving armature when the coil is energized.
A common option for extended environmental protection is a potted or encapsulated coil. Potting or over-molding helps in making the coil humidity/splash resistant (in applications where this is common). If more severe conditions exist, further sealing of the coil cavity may be required.
When energized, the plunger retracts, pulling the load. De-energized, the plunger is extended to specified stroke distance.
An intermittent duty unit with extremely short ON time. A duty cycle is normally in the 10% to 25% range. This is maximum input power for that size solenoid.
If a solenoid is controlled by a transistor which is signaled from a microprocessor, the PWM can be considered as an alternate means for reducing sizes or saving energy. PWM reduces the effective voltage by pulsing the voltage input. For example, if a solenoid has 12 volts supplied, but at 500 Hz at a 50% duty, the solenoid acts exactly as if it is connected to a 6-volt supply. If the duty cycle is changed to 25%, then the solenoid performs like one connected to a 3-volt supply. The frequency must be higher than the solenoid can respond to otherwise chatter or humming will occur. Due to the inductive nature of the solenoid coil, the current is smoothed resulting in a constant force. Initially, the microprocessor must leave the transistor on long enough to allow the solenoid to energize. After that point, the microprocessor must alternately issue ON and OFF pulses to the transistor to achieve the appropiate duty cycle.
When energized, the push rod extends, pushing the load. A push solenoid is actually a pull solenoid with the addition of a push rod that rides against the internal face of the plunger extending through the fixed-pole piece.
A coil whose turns are allowed to wind randomly in no specific pattern. One turn may overlap another or may lay side by side or even spiral completely across the surface of the coil. Normally carries a ±10% tolerance on resistance.
An electrical device for transforming alternating current into direct current.
The ratio of the flux density in a given medium to that which would be produced in a vacuum with the same magnetizing force. Non-magnetic materials, including air, have a relative permeability of 1, while magnetic materials such as iron, have initial relative permeabilities of approximately 2,000.
The magnetism which remains in effect on a piece of magnetic material or between two pieces of magnetic material after the electromagnetic field created by the coil has been removed. An air gap is usually maintained between two magnetic poles to minimize the effects of residual magnetism.
Voltage/Wattage (in operation, the coil resistance will increase due to the heating of the coil wire).
Coil resistance tolerances are generally ±5% for heavier gage wires where precision coil windings are used and ±10% for finer gage wire where random winding processes are used. Tolerances are shown for each solenoid in the individual specification charts.
Return springs are often used to return the plunger and/or push rod back to its original position. Return springs can be internal or external to the solenoid and custom fit for a customer’s unique needs.
The ambient temperature range, voltage fluctuation, return springs and temperature rise all affect the net available output torque or force of a solenoid. A 1.5 safety factor should be applied to preliminary calculations of torque or force.
Standard construction is nominally rated for 1,000,000 cycles. In actual service, cycle life exceeding this figure is constantly being experienced. Periodic cleaning and lubrication will help in extending life. Severe operating conditions—a heavy side load on the plunger, for example, may shorten cycle life. Since many factors other than the solenoid construction itself have this effect, the rated life expectancy is valid only for the laboratory conditions under which life tests were run. Special long-life designs are available.
The small diameter portion of the plunger assembly of a push-type Tubular solenoid which protrudes through the base or stationary pole face and provides push capability; usually made from #303 stainless steel.
The cylindrical bearing in the base of the solenoid which provides a guide for the shaft. Usually made from phosphor bronze, it can be made of other materials for different applications requiring longer life.
Sleeving used on standard Solenoids to insulate the lead wires where they exit the Solenoid case is black Vinylite per Mil-I-631B, Type F, subform Ua, Grade C, Class 1, Category 1, and meets UL files E13565 and E-18459. Sleeving on high-temperature coils is Teflon for temperatures up to 200°C continuous, and will meet the requirements of AMS 3655 and UL files E-20344 and E-39513.
A device comprised of a coil of wire, a housing and a moveable plunger (armature). When an electrical current is introduced, a magnetic field forms around the coil which draws the plunger in. A Solenoid essentially converts electrical energy into mechanical force.
Applications which require different power levels than those available for standard, intermittent or pulse duty cycles. This covers applications at ambient temperature significantly above or below 76°F (25°C), or a desired current drain, below standard value, or a special duty cycle, or other design requirement affecting power.
Electrohydraulic solenoids engineered to deliver performance and safety in harsh environments. These solenoids are designed to operate in extreme temperatures, sealed to withstand water ingression and submersion (up to IP-X9), resist an 800 lb maximum side load and pass a 96-hour salt spray (fog) corrosion test (ASTM B117).
The final stable temperature the coil wire reaches during operation—ambient temperature plus coil heat rise.
The pole or stop is stationary component within the solenoid that attracts the moving armature when the coil is energized.
The stationary component within the solenoid that attracts the moving armature when the coil is energized.
The total movement expected of the solenoid when electrical power is applied. It is also often defined as the air gap between moveable plunger and the fixed-pole piece in the de-energized condition. For greatest efficiency and smallest size, design for the shortest stroke possible.
Coil wrapping tape is clear Mylar brand polyester film 0.002″ thick which has been slit to the desired width and is used to wrap the coil in an overlapping manner. The film is per Mil-I-631 Type G, Form T, Class I, rated for 130°C continuous and meets UL file E-39505. Coil banding tape is Mylar polyester film, adhesive backed per Mil-I-15126 Type MFT. This tape is used to wrap around the O.D. of the coil one thickness of 0.0025″.
Since solenoid output force will continue to improve (though current draw will increase) with ambient temperature decrease, operation of standard designs in an ambient temperature as low as –65°F (–53°C) presents no problem. It is when solenoids will be operated in an ambient environment above 76°F (25°C) that some caution must be taken. If the temperature is significantly above 76°F (25°C), coil burning may occur even if solenoid is operated at its rated duty cycle and voltage. Special high-temperature coil designs are available.
Tubular or cylindrical solenoids offer “maximum” magnetic efficiency and provides the best force/stroke.
The C-Frame or U-Frame solenoid is the most cost effective frame shape but is the least magnetically efficient and provides the lowest force/stroke.
Direct-drive limited motion devices that use a permanent magnetic field and coil winding to produce a force proportional to the current applied to the coil. These Electromagnetic devices are used in linear and rotary motion applications requiring linear force or torque output, and high-acceleration, or high-frequency actuation.
Is the Standard International (SI) unit of electric potential or electromotive force. Voltage can be expressed as an average value over a given time interval, as an instantaneous value at a specific moment in time, or as an effective or root-mean-square (rms) value.
The IEC uses the term “Ingress Protection” to identify the environmental protection of a device. The IP classification system designates, by means of a number, the degree of protection provided by a device against ingress of dust and water. IP-65 identifies dust tight, no dust ingress, protected against jets of water from any direction.
A unit of power equal to current (in amperes) multiplied by voltage (in volts).