月: 2022年12月

What Is a Surge Protector?

A surge protector is a protective device to protect equipment from instantaneous and extremely high voltages and currents caused by lightning strikes and other events.

Surge refers to a voltage of several thousand volts generated by lightning strikes, thunderclouds, and industrial machinery. While lightning is a natural disaster, spot welding, plasma cutting, and other high-voltage operations generate extremely high voltages (spikes) and currents (surges) at the moment of discharge, which can have damaging effects on electronic equipment, controller circuits, and other devices.

Surge protectors are devices designed to mitigate and protect against such incidents. Surge protectors should be installed at the same time the equipment is installed, as surge damage can occur to equipment that may not be affected by surges.

Uses of Surge Protectors

Surge protectors are used where there is concern that equipment may be damaged by high voltage or high current due to lightning strikes or electrical discharges. Specific locations where a surge protector is used are as follows:

• Near induced lightning (abnormally high voltage) from lightning rods, etc. at the time of a direct lightning strike
• Near places where large indirect currents due to electrostatic induction flow from the effects of lightning
• Near power lines and steel towers where high voltage current flows
• Near motor-driven equipment and factories where high voltage and large currents are generated (e.g., automobile repair)
• Locations near arc welding machines that emit noise during arc generation or factories that handle arc welding machines
• Near neon signboards and other areas where high voltage is discharged

Principle of Surge Protectors

A surge protector is a nonlinear element that becomes low resistance when a high-voltage or current surge is applied and releases the surge to the ground side (GND) in a circuit manner. The role of surge protector is to protect various electronic/electrical devices connected to it from damage.

A surge protector incorporates one or more nonlinear elements (elements in which the current flowing through the element is not proportional to the voltage when voltage is applied) to divert surge current and limit over voltage. This element is also called a lightning surge absorber.

Under normal conditions, a surge protector is equivalent to an insulator that does not conduct electricity and has a high resistance to the power supply voltage. When a surge occurs, the built-in nonlinear element instantly changes from a high resistance to a low resistance.

The surge current is then diverted to the ground side, and at the same time, the voltage of the lightning surge is suppressed, after which it returns to its original high resistance, so that the current does not continue to flow. The key to selecting a surge protector is the voltage protection level (maximum surge voltage) based on the residual voltage when the surge is normally handled.

Other Information on Surge Protectors

1. Power Strip Surge Protectors

Surge protectors are built into some of the power outlet taps that are frequently used in homes and offices. In this case, the device used for the surge protector application is a lightning surge absorber, commonly known as a varistor.

Varistor is an abbreviation for “voltage variable resistor.” Generally, multilayer chip ceramics are used, and when a certain threshold voltage is exceeded, the device can conduct a large current due to the quantum mechanical tunneling effect.

Although it is possible to configure a circuit with the same function using a forward/reversing diode and parallel capacitance, varistors are usually used because of their disadvantage in terms of area. Protection circuits using varistors are not limited to power strips, but are used in a wide variety of electronic and electrical equipment. 

2. Performance Indicators of a Surge Protector

One of the performance indicators of a surge protector is the maximum surge voltage, which is specified in public standards, including the measurement method.

What Is a Thermistor Sensor?

A thermistor sensor, short for “thermally sensitive resistor,” is an electronic component that exhibits a significant change in resistance in response to temperature variations.

These sensors enable temperature measurement by monitoring the resistance of the component. Thermistor sensors are manufactured using a mixture of various metals and can operate within a temperature range of approximately -50°C to 150°C.

Uses of Thermistor Sensors

Due to their affordability, temperature-sensing capabilities, compact size, and durability, thermistor sensors find applications in a wide array of fields:

1. Medical Equipment: Thermistor sensors are used in medical devices for temperature monitoring.

2. Automobiles: They play a crucial role in measuring the temperature of the engine and outside air, ensuring optimal engine combustion and performance.

3. Office Automation (OA) Equipment: Thermistor sensors are employed in various office equipment, including printers and copiers, for temperature control and monitoring.

4. Housing Equipment: These sensors are used in household appliances like water heaters and cooking appliances to measure and control temperature.

5. Industrial Equipment: Thermistor sensors contribute to temperature control in industrial machinery and equipment.

6. **Information Equipment:** They are used in data centers and servers for temperature monitoring and control.

7. General Household Appliances: Thermistor sensors can be found in various household appliances for temperature measurement and control.

For example, air conditioning systems use these sensors in both indoor and outdoor units to maintain optimal temperature conditions. In automobiles, they help control engine temperature and monitor external air temperature. In water heaters, they regulate the water temperature coming out of faucets.

Principle of Thermistor Sensors

Thermistors are made from a mixture of materials, with different types available:

– NTC (Negative Temperature Coefficient) Thermistors: Their resistance decreases as temperature increases, and they are commonly used for temperature measurement and compensation circuits.

– PTC (Positive Temperature Coefficient) Thermistors: These thermistors are used to protect devices from overcurrents rather than for temperature measurement. Their resistance value increases significantly near a specific temperature as temperature rises.

– CTR (Current-Time Resistor) Thermistors: Similar to NTC thermistors, their resistance decreases as temperature rises, but their resistance value decreases significantly at higher temperatures.

Other Information on Thermistors

When using thermistor sensors in electrical circuits, they are typically integrated into the circuit with a constant supply voltage and fixed resistors. As the resistance of thermistor sensors changes with temperature, variations in temperature lead to changes in current flow and voltage across the resistor.

These voltage variations can be read by microcontrollers or other devices with analog-to-digital converter (ADC) capabilities. The combination of thermistor sensors and peripheral circuits often involves connecting a pull-down resistor of 1 kilo-ohm or 10 kilo-ohm to a constant voltage source (e.g., 5 V DC or 3.3 V DC) or connecting a pull-down resistor between the thermistor sensor and ground (GND).

It’s essential to choose appropriate resistor values to prevent excessive heat generation due to increased current flow through the resistor, which can result in inaccurate measurements. In some cases, a known resistor is combined with the thermistor sensor to measure resistance values accurately.

What Is a Samarium Cobalt Magnet?

A samarium cobalt magnet, a type of rare-earth magnet, is predominantly composed of samarium and cobalt. Known for its strong magnetic force and excellent heat resistance, it does not require plating due to its rust resistance. However, it is prone to chipping and is extremely brittle due to its high hardness.

Applications of Samarium Cobalt Magnets

These magnets are used in high-temperature environments, such as in microwave ovens and magnetrons, automotive motors and ignitions, and various compact devices like actuators, magnetic sensors, microswitches, small relays, and laser devices. Their heat resistance and compactness make them versatile for both industrial and smaller-scale applications.

Properties of Samarium Cobalt Magnets

With samarium and cobalt as their primary components, these magnets boast a high Curie temperature (700 to 800°C), enabling them to maintain magnetism in high-temperature conditions. Their rust resistance stems from the absence of iron. Despite their advantages, the rarity of the materials makes them expensive and subject to price fluctuations.

Other Information on Samarium Cobalt Magnets

1. Ignition Risks

Samarium cobalt magnets can ignite under certain conditions, especially when polished surfaces come into contact with air. They are brittle and can produce flammable metallic powders upon impact. Therefore, they are classified as hazardous materials, necessitating careful handling to prevent the formation of potentially flammable powder.

2. History of Samarium Cobalt Magnets

Research into rare earth magnets began in the 1960s, leading to significant advancements in magnet technology. The discovery in the 1970s that samarium combined with cobalt could dramatically improve magnet performance led to the invention of the samarium cobalt magnet by Dr. Yoshio Tawara in Japan. This magnet’s development, including the Sm2(Co,Fe,Cu,Zr)17 composition, enabled the miniaturization of devices like Sony’s first-generation Walkman.

What Is a Thumbwheel Switch?

A thumbwheel switch is a device used for settings that convert the ON/OFF signals of multiple contact circuits into binary, decimal, hexadecimal, or other codes. This conversion is achieved by turning a disc-shaped part known as a rotor. The switch is sometimes referred to as a digital switch or thumbwheel switch.

There are two main types of thumbwheel switches: rotary switches, operated by rotating the switch with a finger, and push switches, activated by pressing a button.

Some thumbwheel switches come with a lock function to prevent accidental changes to the set value, requiring a thin pen nib for operation.

Uses of Thumbwheel Switches

Thumbwheel switches vary in size, with smaller switches typically used in office equipment and consumer electronics, and larger ones in industrial equipment and machine tools.

In industrial equipment and machine tools, these switches are utilized to set operational control values such as time, temperature, and number of cycles. In machine tools, they are used to set dimensional limits for machining, and in motor control, to set microstep counts.

They are also employed in various measuring instruments for setting measurement conditions like frequency, temperature, and time.

Principles of Thumbwheel Switches

Thumbwheel switches consist of simple components such as a case, slide, rotor, sealing plate, packing, printed circuit board, mounting plate, and, for push-operated models, a push button. They are versatile and used in a wide range of applications.

The selected number is visually confirmed on the switch, reducing the likelihood of incorrect inputs. Mistakes can be easily corrected, adding to the usability of these switches.

Since a mechanical mechanism is used for code conversion, the set value remains preserved even during power outages. This mechanical nature also simplifies the circuit and wiring requirements on the output side, enhancing both reliability and maintainability.

Thumbwheel switches are particularly effective in applications where parameters need frequent adjustments according to operating conditions. While many modern systems use large-screen operation panels for parameter settings, there are still numerous instances where hardware-based setting changes are necessary in field conditions.

What Is an RF Shielded Room?

An RF shielded room is a room designed to block the effects of external electromagnetic waves and magnetic fields that adversely affect electrical and electronic equipment, and to prevent the emission of electromagnetic waves and magnetic fields to the outside.

Electronic devices that use electricity generate electromagnetic waves, and thus electronic devices and equipment are constantly affected by various electric fields. It is also highly likely that they have an effect on their surroundings. A major role of RF shielded rooms is to eliminate the effects of these electromagnetic waves.

RF shielded rooms are covered with conductive materials such as metal or wire mesh. It may be constructed from new construction, or in the case of an existing building, assembled with panels that can be assembled inside. The purpose of use, the measurement details, and the location where you want to install it. The design is based on the environment and other factors.

Uses of RF Shielded Rooms

RF shielded rooms are used to eliminate the adverse effects of electromagnetic waves. Specific applications are as follows:

• Measurement rooms with bio-magnetic field measurement equipment, such as MRI, magnetoencephalography, and magnetocardiography
• Computer rooms for confidentiality purposes
• Measurement rooms for electromagnetic interference and laboratories for signal evaluation without the influence of electromagnetic interference
• Recording studios

It is used to provide an environment for product development and quality control of precision instruments and electronic devices. RF shielded rooms are also used to prevent electromagnetic noise (unwanted radio waves) generated by equipment and devices inside a facility from affecting equipment and devices outside the facility.

Principle of RF Shielded Room

Electromagnetic shielding uses the property of conductive materials such as wire mesh and metal plates to reflect electromagnetic waves. RF shielded rooms are rooms covered with these conductive materials.

What is important in producing RF shielded rooms is not only to shield the electromagnetic waves generated in the space or influenced by the outside, but also to shield the electromagnetic noise leaking from both sides. In particular, shielding of openings (doors, windows, air conditioning openings, etc.) is a key point.

RF shielded rooms can be classified into the following three categories according to the purpose and frequency range to be handled.

• For Electrostatic Shielding
  RF Shielded Rooms are used to maintain a constant electric potential in a room. (EEG rooms, hearing test rooms, etc.)
• For Magnetic Shielding
  RF Shielded Rooms are generally used for geomagnetic fields up to 10 kHz
• For Planar Electromagnetic Shielding
  RF Shielded Room for 10kHz to 40GHz. (Noise testing rooms for electronic equipment, anechoic chambers, recording studios, etc.)

Shielding in EMC countermeasures often refers to electromagnetic shielding. Electromagnetic shielding is often used for EMC and immunity measures for electronic equipment.

Other Information on RF Shielded Rooms

1. Difference Between Rf Shielded Room and Anechoic Chamber

RF shielded rooms are characterized by shielding the entire room, down to the doors, air conditioning, and power supply, in order to shield electromagnetic waves. On the other hand, an anechoic chamber is further covered with a radio wave absorber to suppress the reflection of radio waves completely.

The absorber has a spongy, thorny shape and contains carbon powder and ferrite components. By covering the entire surface of the room with the absorber, the incident electromagnetic waves can be attenuated to about 1/100,000 of their original volume. Electromagnetic waves cannot exist in an anechoic chamber, which is sometimes called a radio wave anechoic chamber. 

2. Antenna Evaluation in an Anechoic Chamber

While the main purpose of RF shielded rooms is to evaluate the quality of the target signal itself by blocking out interference and noise, antenna emission tests are often conducted in an anechoic chamber, taking advantage of the non-reflective nature of electromagnetic waves.

Directionality testing of radio waves is essential for mobile communications, including millimeter wave, automotive radar, and sensing technology. An anechoic chamber is an indispensable environment for evaluating the shape of the radiated beam of an antenna and the electrical characteristics of the antenna itself.

3. Shield Boxes and Anechoic Chambers

Since an anechoic chamber is a very large device, it is costly, including maintenance. RF shielded rooms are less expensive than anechoic chambers because of the radio wave absorber, but still have a certain cost.

Similarly, an anechoic box type is also widely used for various evaluation purposes because of its convenient size.

What Is a Jet Oiler Spout?

A jet oiler spout is a device designed for lubricating machinery and equipment effectively.

It is particularly useful for supplying oil to areas prone to friction and high-speed rotating parts. Jet oiler spouts operate by injecting jets of oil using compressed air, ensuring efficient lubrication and cooling.

These spouts disperse oil in the form of a fine spray, ensuring uniform distribution on the machine’s friction surfaces for effective lubrication. This helps in maintaining smooth machine operation and prevents wear and heat-related breakdowns.

However, it’s important to note that jet oiler spouts, as they spray oil, can pose a risk of oil leakage from the nozzle and connections. Proper sealing and leakage prevention measures are necessary to avoid environmental and workplace issues due to oil leakage.

Uses of Jet Oiler Spouts

Jet oiler spouts find applications in various fields:

1. Transportation Equipment

In ships, these spouts are used to lubricate high-speed rotating parts such as main engines and rudder wheels, ensuring efficient and stable machinery operation.

They are also employed in airplanes for lubricating high-speed rotating parts like engine drive units and turbochargers, contributing to optimal engine performance, efficiency, and reliability. In automobiles and motorcycles, they enhance component durability and fuel efficiency.

2. Energy Industry

In the energy sector, jet oiler spouts are used in power plants to lubricate high-speed rotating parts of turbines and generators, ensuring efficient power generation and stable operation. They are also employed in wind turbines to extend machine life and improve power generation efficiency.

3. Manufacturing

Machine tools like milling machines and drilling machines use jet oiler spouts to lubricate cutting tools and bearings of rotating parts, reducing friction, and improving precision and tool lifespan. In press machines, these spouts are used for lubricating press parts and dies, enhancing quality and tool longevity. They are also employed in conveyors to lubricate rollers and bearings.

Principle of Jet Oiler Spouts

Jet oiler spouts are designed to drip or inject oil or adhesives, allowing precise control over the quantity and location of the discharge. They are smaller in size compared to sprays and jockeys, making them space-efficient for storage.

These devices consist of a tank and nozzles. The tank stores a fixed amount of lubricating oil and dispenses it as needed. Tank sizes range from small ones (20 ml or less) to large ones (400 ml or more), with smaller oilers being suitable for easily degradable liquids.

Nozzles equipped with fine holes and jets inject oil in the form of a fine spray or jet. Ultra-fine nozzle types are available for use in extremely confined spaces. Jet oiler spouts can be made from metal or plastic, and the choice of material should match the type of liquid used.

How to Select a Jet Oiler Spout

When choosing a jet oiler spout, consider the handle and other features. There are two main types: those with a grip lever and those with a pushable plastic tank body. Selection should be based on ease of use and intended application.

The tank’s capacity is another factor to consider. Opt for a larger oiler if you require a significant amount of oil or are working with a non-degradable liquid.

Nozzles come in various shapes, including horizontal or slightly curved tips, and straight-up, or angled nozzles. Select the nozzle shape that best suits your specific application requirements.

What Is Coating Process Equipment?

Figure 1. Types of Coating Equipment

Coating process equipment is used to apply chemicals to products or materials.

Coating process equipment generally uses various coating methods such as roll coaters, spin coaters, dip coaters, spray coaters, and dispense coaters, depending on the shape of the object to be coated, the chemical to be coated, and the purpose of the coating.

In recent years, coating process equipment has evolved dramatically along with improvements in coating technology, as precision coating accuracy is required in industrial fields such as semiconductor manufacturing, flat panel display (FPD) manufacturing, solar cell and rechargeable battery manufacturing.

Uses of Coating Process Equipment

Coating equipment is used to apply coating liquids to objects in a variety of manufacturing processes, such as in the semiconductor field and secondary battery manufacturing. Spin coating process equipment is often used to apply photoresist in the photolithography process in the semiconductor and flat panel display (FPD) manufacturing fields, which require particularly thin, high-performance, high-density devices such as PCs, LCD TVs, smart phones, and tablets.

For functional films and sheet products used in rechargeable batteries, solar cells, automotive parts, housing construction materials, textiles, medical care, etc., roll, spray, and dispense coating process equipment are used to apply chemicals such as sealants, adhesives, and electrode materials.

Principle of Coating Process Equipment

Figure 2. Features of Coating Equipment

Coating process equipment is used to apply materials such as correspondence and chemicals to various production materials. They can be broadly classified into roll, spin, spray, and dispense dispensing systems.

1. Roll Coating Process Equipment

Roll coating process equipment is generally used for coating relatively thin and flat materials such as films and sheets.

Various coating methods are used depending on the nature and viscosity of the chemical to be applied and the film thickness to be applied, such as gravure coaters and reverse coaters that use the rotation of a roller in contact with a liquid reservoir of the chemical to be applied and the winding rotation of the film or sheet material.

Roll-to-roll coating is possible, and this method is most suited for high-speed coating. The characteristic feature of these methods is that a bead is formed between the coating liquid and the object to be coated, and the object to be coated or both the object to be coated and the roll are moved or rotated to apply shear force to the coating liquid and thinly apply it.

Stabilizing this bead is essential for high-quality coating.

2. Spin Coating Process Equipment

Spin coating process equipment is used in the photolithography process in the semiconductor and flat panel display (FPD) manufacturing fields. This is the thinnest coating method.

This is the thinnest coating method, but it is not suitable for mass production because it cannot apply multiple coats and continuous production is not possible.

3. Spray Coating Process Equipment

Spray coating process equipment converts chemicals into fine particles and applies them to automobiles, exterior walls, building materials, and other large objects.

Three types of methods exist for generating granular spray: air, electric, and ultrasonic.

4. Dip Coating Process Equipment

Dip coating process equipment is a method in which the object, regardless of its shape, is dipped into the dip coating solution and pulled up. It can form a uniform thin film and is used for optical lenses, medical systems, electronic devices, and other applications.

Dip coating process equipment is characterized by its ability to form a uniform thin film with minimal loss of coating solution, regardless of the shape of the object.

5. Dispensing Coating Process Equipment

Dispensing coating process equipment is used in situations where relatively precise linear coating is required. This coating process equipment is equipped with a dispensing mechanism that can control the amount of coating, and when even more precise coating is required, a robot is used to provide both accuracy and precision in the amount of coating. Although the dispensing speed is of course inferior, spot dispensing to small areas and coating films of complex shapes can be formed.

Other Information on coating process equipment

Coating Defects and Coating Process Equipment

Figure 3. Lack of Coating and Coating Equipment

No matter how sophisticated the Coating Process Equipment is, a clean coated surface may not be obtained depending on the coating conditions, such as a coating fluid with an incompatible viscosity or coating speed. The types of coating defects and their remedies are as follows.

1. defects caused by coating

Defect	Cause	Remedy
Air entrainment	Occurs when air cannot escape during the application of the coating liquid to the coated object.	Solved by reducing the coating speed.
Livestock	This occurs when there is a reverse pressure gradient in the coating section in the direction of the coating.	Solution is to reduce the viscosity of the coating liquid and the coating speed.
Strips and holes caused by air bubbles	This is caused by the presence of bubbles in the coating liquid.	Take measures to eliminate bubbles.
Uneven horizontal damping	Occurs mainly in reverse gravure coating systems.	Solution is to suppress vibration of the coated object or change the rotational speed of the gravure.
Unevenness	Unevenness is caused by the flow of coating liquid in the coating film.	This is solved by improving the coating liquid.
Foreign matter	Coating liquid agglomerates or becomes gelatinous.	This can be solved by introducing a filter, etc.
Flickering is caused by the high surface tension of the coating solution.	This is caused by the high surface tension of the coating liquid.	Add a surfactant or other agent.

2. Defects caused by drying

Defect	Cause	Remedy
Yuzuhada (uneven coating surface like yuzu peel)	This defect occurs when the drying speed is too fast.	This defect is caused by drying too fast, and can be corrected by reducing the drying speed or adding a surfactant.
Wind ripples	Occurs during hot-air drying.	This is caused by hot-air drying, and can be handled by reducing the speed of the hot-air blow.
Cracking	Occurs due to shrinkage of the coating film.	It can be solved by reducing the thickness of the coating.

Coating is a technology that can be achieved by appropriately selecting Coating Process Equipment, Drying, and Coating Liquid. It is important to select the appropriate Coating Process Equipment, taking into consideration the conditions of the coating liquid to be used and the specifications of the drying oven.