0
They do not absorb water and do work under water, if that's what you mean. Electromagnets can be made for underwater applications as well.
Wiki User
∙ 11y ago
Add your answer:
Earn +20 pts
Is a36 steel magnetic?
A36 is paramagnetic. It is fairly good conductor of magnetic field, and it will be atracted to magnets strongly. As far as residual magnetism (can it be magnetized) I don't know for sure. I know you can not make usefully strong magnets out of A36 material, but it may have some residual magnetism.
What is IP30 Conformity?
An IP rating determines the level of ingress protectionthat the device is rated for. Ingress protection ratings determine how dust-resistant and water-resistant a given device is. An equivalent rating but is not likely to be common is a IK rating (which determines shock resistance)For every IP rating there are two digits - the first one being dust resistance and the second for water resistance. If there's a X on either digit, this means that the tests for this particular characteristic haven't been performed, rated, or there's no resistance.Most of the time you will see ratings like IP67 or IP68 - this means that (6) is dustproof and (7) or (8) is waterproof at somewhere around 3 to 5 feet underwater for up to about 30 minutes.
What is the difference between an electric motor and an electric generator?
HOW ARE ELECTRIC GENERATORS DIFFERENT THAN MOTORS? There is no fundamental difference between an electric motor and an electric generator or dynamo. In normal use, all motors behave as generators, and all generators behave as motors. DC Motors act like generators because they use less electrical energy when allowed to spin fast. DC generators act like motors because they become easier to spin when less electrical energy is drawn from their terminals. For example, connect two small DC magnet motors together. Then if you spin the shaft of the first motor, the second motor's shaft will start spinning too. One acts as a DC generator, and the other acts as a DC motor. Or, spin the second one's shaft, and the first one will start spinning. Another example: If you connect a small DC motor to a small battery, then an electric current will appear in the motor's coils, and the motor starts spinning. But if you spin the motor's shaft slightly faster than the normal speed, the direction of current in the circuit will reverse, and the battery starts taking in energy from the motor. The motor has become a generator, and it's recharging the battery. Here's a good way to visualize what's happening. Imagine two pulleys connected by a rubber drive-belt. If you spin the first pulley, it pumps the belt into motion, and the second pulley starts spinning. Ask yourself this: which one is the generator? Answer: both and neither. A pulley is just a pulley. Of course we can *force* a pulley to behave like a motor: let the pulley rub against a moving belt, and the pulley will start spinning. Or we can turn it into a generator: turn the pulley, and the belt will be forced to move. In electric circuits the wires contain a circular "belt" made of electric charges (the electron-sea within the metal.) And as with the pulleys, the "belt" inside an electric circuit will slowly move along just like a leather belt. (You cannot see individual electrons, so when crowds of electrons start moving inside the wires, you cannot see any motion.) Or pretend that you have two water pumps which are connected together with hoses. Fill the pumps and the hoses with water. Now, when you turn the first pump, the pressure inside the "water circuit" drives the second pump into motion. This shows you that all pumps are motors, and all motors are pumps. It just depends on for which purpose they're employed. COILS AND MAGNETS Here's a simple electrical experiment which shows what's happening with motors and generators. Get two coils of wire wrapped on hollow plastic spools. Connect their wires together. Get two powerful bar-magnets and place the end of each magnet inside each spool. Now if you jerk one magnet suddenly, the other magnet will feel a kick. What happened? By suddenly yanking the first magnet, the first coil created a voltage because of "Lenz-Law Induction." This voltage caused all the charge in both coils to begin moving along. That created a magnetic field in the second coil, which gave the second magnet a kick. Motors and generators are based on this phenomenon. AC MOTORS AS GENERATORS But what about AC motors? And what about DC motors which use a "field coil" but no permanent magnets? If you spin either of these, a voltmeter will show no voltage. It's because you aren't using them correctly. To act as a generator, an AC motor needs to be connected to a power grid or to a large-value capacitor. And a DC field motor needs to be connected correctly (series-wound motors must be shorted, while parallel-wound motors must be left open.) And finally, these types of motors can only generate a voltage/current if they're spinning FAST. It takes awhile for tiny initial currents to build up. When no permanent magnets are present, and all you have are moving coils and pieces of metal, it takes current to make current. The current and voltage gradually build up because of a positive-feedback process, and this process doesn't kick in until the motor's shaft is turning faster than a certain speed. MODERN MOTORS DISCOVERED ACCIDENTALLY The modern DC motor was not designed as a motor. In the middle 1800s, inventor Zenobe Gramme was trying to build an electric generator which gave a very smooth output voltage. He did this by using many coils with overlapped fields. Because of it's smooth DC output, such a generator could replace large banks of batteries being used at the time. In 1873 one of his assistants accidentally connected two of his generators together. The first generator was being spun by a steam engine, and the second one unexpectedly started spinning like a motor. The "Gramme Machine" has been used ever since, under the name "DC motor" or "DC generator."
Working of camless engine with electromechanical valve actuator?
INTRODUCTIONThe cam has been an integral part of the IC engine from its invention. The cam controls the "breathing channels" of the IC engines, that is, the valves through which the fuel air mixture (in SI engines) or air (in CI engines) is supplied and exhaust driven out. Besieged by demands for better fuel economy, more power, and less pollution, motor engineers around the world are pursuing a radical "camless" design that promises to deliver the internal - combustion engine's biggest efficiency improvement in years.Cams, lifters, pushrods... all these things have up until now been associated with the internal combustion engine. But the end is near or these lovely shiny metal objects that comprise the valve train hardware in your pride and joy. Camless engine technology is soon to be a reality for mass-produced vehicles. In the camless valvetrain, the valve motion is controlled directly by a valve actuator - there's no camshaft or connecting mechanisms. Various studies have shown that a camless valve train can eliminate many otherwise necessary engine design trade-offs. Automotive engines equipped with camless valve trains of the electro-hydraulic and electro-mechanical type have been studied for over twenty years, but production vehicles with such engines are still not available. The issues that have had to be addressed in the actuator design include:• Reliable valve performance cost• packaging• power consumption• noise and vibrationNoise has been identified as the main problem with the electromechanical actuator technology, arising from high contact velocities of the actuator's moving parts. For this noise to be reduced, a so-called soft-landing of the valves has to be achieved.The valvetrain in a typical internal combustion engine comprises several moving components. Some are rotating and some are moving in a linear manner. Included are poppet valves that are operated by rocker arms or tappets, with valve springs used to return the valves to their seats. In such a system the parasitic power losses are major - power is wasted in accelerating and decelerating the components of the valvetrain. Friction of the camshaft, springs, cam belts, etc also robs us of precious power and worsens fuel economy, not to mention contributing to wear and tear. The power draw on the crankshaft to operate the conventional valve train is 5 to 10 percent of total power outputAnother factor working against the conventional valve train is that of the cam profile. Usually, it is fixed to deliver only one specific cam timing. The cam lobes have to be shaped such that when the valve travels up and down at the engines maximum speed it should still be able to slow down and gently contact the valve seat. The valves crashing down on their valve seats results in an engine that is real noisy and has a short life expectancy.Having different cam profiles will result in different engine characteristics. While high-rpm power and low rpm-torque can be each optimized, a compromise is required to obtain the best of both in the same engine. With Variable Valve Timing (VVT) technologies the compromise is getting better and better - reasonable low down torque and high-speed power are being produced by many sub 2-litre engines.But the problem remains that the cam grind is still a fixed quantity - or two fixed quantities in the case of Honda V-TEC engines. That's why the Electromechanical Valve Train is considered the next evolution of VVT. With the potential to dial in any conceivable valve timing at any point of the combustion cycle for each individual cylinder, valves can be opened with more lift and/or duration, as the computer deems necessary.Conventional valve train mechanismPushrod engines have been installed in cars since the dawn of the horseless carriage. A pushrod is exactly what its name implies. It is a rod that goes from the camshaft to the top of the cylinder head which push open the valves for the passage of fuel air mixture and exhaust gases. Each cylinder of a pushrod engine has one arm (rocker arm) that operates the valves to bring the fuel air mixture and another arm to control the valve that lets exhaust gas escape after the engine fires. There are several valve train arrangements for a pushrod.CrankshaftCrankshaft is the engine component from which the power is taken. It receives the power from the connecting rods in the designated sequence for onward transmission to the clutch and subsequently to the wheels. The crankshaft assembly includes the crankshaft and bearings, the flywheel, vibration damper, sprocket or gear to drive camshaft and oil seals at the front and rear.CamshaftThe camshaft provides a means of actuating the opening and controlling the period before closing, both for the inlet as well as the exhaust valves, it also provides a drive for the ignition distributor and the mechanical fuel pump.The camshaft consists of a number of cams at suitable angular positions for operating the valves at approximate timings relative to the piston movement and in the sequence according to the selected firing order. There are two lobes on the camshaft for each cylinder of the engine; one to operate the intake valve and the other to operate the exhaust valve.PROBLEMS RELATED TO CONVENTIONAL VALVE TRAINThe poppet valves that are operated by rocker arms or tappets, with valve springs used to return the valves to their seats. In such a system the parasitic power losses are major - power is wasted in accelerating and decelerating the components of the valve train. Friction of the camshaft, springs, cam belts, etc also robs us of precious power and worsens fuel economy, not to mention contributing to wear and tear. The power draw on the crankshaft to operate the conventional valve train is 5 to 10 percent of total power output.Another factor working against the conventional valve train is that of the cam profile. Usually , it is fixed to deliver only one specific cam timing. The cam lobes have to be shaped such that when the valve travels up and down at the engines maximum speed it should still be able to slow down and gently contact the valve seat.The single lobed cam is designed to operate the valves at only specific periods of the Otto cycle, thus preventing the engine from achieving maximum torque at higher rpms. The opening and closing of the valves is constrained by the geometry of the cam profile.ELECTROMECHANICAL CAMLESS VALVE ACTUATORIn recent years camless engine has caught much attention in the automotive industry. Camless valve train offers programmable valve motion control capability. An EMV system consists of two opposing electromagnets, an armature, two springs and an engine valve. The armature moves between the two magnets. When neither magnet is energized, the armature is held at the mid-point of the two magnets by the two springs located on either side of the armature. This system is used to control the motion of the engine valve. The engine valve is then in turn used to control the flow of air into and out of a combustion engine cylinder. The camless engine, where lift and valve timing can be adjusted freely from valve to valve and from cycle to cycle. It also allows multiple lift events per cycle and, indeed, no events per cycle-switching off the cylinder entirely.Computer controlled- opening and closing of valves make it possible to optimize the various phases of engine running. During idling phases, specific intake valve opening strategies make it possible to admit just the necessary quantity of air without having recourse to throttling the intake with a butterfly valve, something that generates consumption of fuel not used by the engine. Timing of valve opening or the latitude to only open a single intake valve make it possible to stabilize the engine on idling points which consume little fuel while ensuring a good level of drive ability or the driver.During urban driving and on the open road, both adequate opening and timing of the valves make it possible to admit a quantity of air limited to the requirement so the engine mixed with a massofburned gases purposely retained in the engine. This strategy ensures reduction of fuel consumption, polluting exhaust emissions, in particular, nitrogen oxides, produced by the engine. In terms of performance, the modularity of the system makes it possible to maximize the massof fresh air trapped in the cylinder at all engine speeds, ensuring both good torque and high power.Apart from these advantages, deactivation of the cylinder also delivers additional savings in terms offuel consumption and exhaust emissions when the engine is only using a small amount of its power as, or example, in urban use. In this mode, only halfof the cylinders are used to provide energy to the wheels, significantly limiting losses due to poor engine efficiency. The camless system is there or system which, on an air aspirated supercharged engine provides the customer with a significant improvement in engine features. In addition, it is a system that has a strong potential or evolution and its functions will be consumption required in order to implement combustion through auto-ignition, such as the HCCI system, which is under consideration as the next stage in the battle to reduce fuel consumption.Electromechanical Valve Train is considered the next evolution of VVT. With the potential to dial in any conceivable valve timing point of the combustion cycle for each individual cylinder, valves can be opened with more lift and/or duration, as the computer deems necessary. Just imagine that you have your latest 2-litre 16-valve EMVT powered engine on the dyno after installing an exhaust. Simply changing a couple of numbers on the computer will have a set of completely revised valve timing maps to suit your exhaust - or cold air intake for that mater. There will be no need for expensive cam changes that may not even give the results you are after. Electronically altering valve events will have a far more major impact on engine performance than any current electronically-controlled item.CONTROL DESIGNWhen the valve-closing event starts, the lower solenoid coil is deactivated, and the valve moves up towards its seating position by the mechanical spring force. An electro mechanical valve actuator works according to the spring-mass pendulum principle, which means that the system follows its own natural oscillation frequency, and external electromagnetic force is only needed for overcoming the friction loss. The electromagnetic actuator is only effective in a relatively short range closing to the seating position, and so it is not efficient in the sense of energy consumption to apply closed-loop control when the valve is still far away from theseating position. The system goes unstable as the engine valve moves to the region within one-third of the total lift.This type of system uses an armature attached to the valve stem. The outside casing contains a magnetic coil of some sort that can be used to either attract or repel the armature, hence opening or closing the valve.Most early systems employed solenoid and magnetic attraction/repulsion actuating principals using an iron or ferromagnetic armature. These types of armatures limited the performance of the actuator because they resulted in a variable air gap. As the air gap becomes larger (ie when the distance between the moving and stationary magnets or electromagnets increases), there is a reduction in the force. To maintain high forces on the armature as the size of the air gap increases, a higher current is employed in the coils of such devices. This increased current leads to higher energy losses in the system, not to mention non-linear behaviour that makes it difficult to obtain adequate performance. The result of this is that most such designs have high seating velocities (ie the valves slam open and shut hard!) and the system cannot vary the amount of valve lift.The electromechanical valve actuators of the latest poppet valve design eliminate the iron or ferromagnetic armature. Instead it is replaced with a current-carrying armature coil. A magnetic field is generated by a magnetic field generator and is directed across the fixed air gap. An armature having a current-carrying armature coil is exposed to the magnetic field in the air gap. When a current is passed through the armature coil and that current is perpendicular to the magnetic field, a force is exerted on the armature.When a current runs through the armature coil in either direction and perpendicular to the magnetic field, an electromagnetic vector force, known as a Lorentz force, is exerted on the armature coil. The force generated on the armature coil drives the armature coil linearly in the air gap in a direction parallel with the valve stem. Depending on the direction of the current supplied to the armature coil, the valve will be driven toward an open or closed position. These latest electromechanical valve actuators develop higher and better-controlled forces than those designs mentioned previously. These forces are constant along the distance of travel of the armature because the size of the air gap does not change.The key component of the Siemens-developed infinitely variable electromechanical valve train is an armature-position sensor. This sensor ensures the exact position of the armature is known to the ECU at all times and allows the magnetic coil current to be adjusted to obtain the desired valve motion.The ability of the electromechanical valve actuator to generate force in either direction and to vary the amount of force applied to the armature in either direction is an important advantage of this design. For instance, varying the value of the current through the armature coil and/or changing the intensity of the magnetic field can control the speed of opening and closing of the valve. This method can also be used to slow the valve closure member to reduce the seating velocity, thereby lessening wear as well as reducing the resulting noise.A special software algorithm is used to control the actuator coil currents such that the valves are decelerated to a speed near zero as they land - in conjunction with a switching time of barely three milliseconds. For the valves this means minimal wear and minimum noise generation. The 16-valve four cylinder engine that is currently undergoing tests in Germany, by Siemens, is equipped with 16 valve actuators and the corresponding armature-position sensors. A ECU is used and two cable rails connect the actuators to it. A 42-volt starter-generator provides the power.WORKINGCamless engines generally employ one of two types of camless actuators: electro-hydraulic or electro-mechanical valve actuators. The actuators receive input from the ECU via a dedicated CAN bus to open and close the poppet valves at a prescribed crankshaft angle timing, transition time and lift, matching the valve timing request sent by the ECU. Feedback is then sent by the actuators through the CAN bus to verify the actual occurrence of the operation.Electromechanical actuators are generally made with two solenoids and two springs. As can be seen in Figure 1 the ECM receives input from the crankshaft position sensor to close the valve, which activates Solenoid 1 by taking current from the battery. The current is passed through a pulse width modulator which tunes the amplitude of the current to control the speed of valve seating. The magnetic field created by Solenoid 1 attracts the armature in the upper position. Spring 1 is compressed and thus closes the valve. Solenoid 2 pulls the armature down to open the valve as shown in Figure 2.
What are some names of small magnets?
Refrigerator magnets, car magnets, neodymium magnets are names of small magnets.
Is the at 19 waterproof action camera waterproof?
If they say its waterproof then im pretty sure its waterproof , they would'nt say that it is waterproof if it isn't cause then they will be getting all those waterproof camera's back!
HOW DO YOU use waterproof in a sentence?
my watch was waterproof. My eyelkiner isn't waterproof and we're swimming today! I have waterproof mascara! The waterproof camera can take underwater pictures! The waterproof safe can be stored underwater!
How do you make a flying car with magnets?
put magnets and put magnets on a car and put magnets on a car and put the car on the road and put the magnets on the road and put the magnets touch the magnets on the road and on the car
Is the Polaroid Cube waterproof?
No, the camera is not waterproof, but you can purchase a waterproof case for it separately.
Are metamorphic rocks waterproof?
they are waterproof
Is the enV3 waterproof?
No phone is waterproof.
Are the shoes that contain continuum waterproof and breathable or just waterproof?
Just waterproof ,if they are breathable they are not waterproof because water will get inside the shoes
Where can you get waterproof towels?
There is no such thing as a waterproof towel. Have a nice day (without waterproof towels) :) :)
Is cashmere waterproof?
Cashmere is not waterproof but you can put on a special fabric finish that can make it waterproof.
Is beaver fur waterproof?
yes it is waterproof. they coat their fur with castoreum to make it waterproof.
Do you need to waterproof timberlands?
No, they come waterproof.
