German Seika sensors Seika models Seika prices

Seika sensors are components that convert changes in non-electrical quantities (such as speed and pressure) into changes in electrical quantities. Depending on the non-electrical quantity being converted, they can be classified into pressure sensors, speed sensors, temperature sensors, etc., and serve as parts and accessories for measurement and control instruments and equipment.

Seika sensor working principle

The magnetic induction sensor is a contact sensor; its structural schematic is shown in the figure. It consists of two alloy reeds with high magnetic permeability and low coercivity, sealed in a glass tube filled with inert gas. The two reeds maintain a certain overlap and an appropriate gap, with gold-plated ends serving as contacts and leads welded outside the tube. When the magnetic flux density at the sensor's location is sufficiently high, the two reeds attract each other, causing the contacts to close; when the magnetic field weakens to a certain extent, the reeds release under their own elastic force. When driven by a permanent magnet, magnetic induction sensors are mostly used for detection, such as limit switches, replacing travel switches that rely on collision contact, thereby improving system reliability and service life. They are often used in PLC controllers as communication signals for position control.

Seika sensor precautions

The voltage used for DC magnetic induction sensors is generally 3~30V DC, and the typical application voltage range is usually 5~24V DC. Excessively high voltage causes internal component temperature rise, making the sensor unstable, while excessively low voltage makes it susceptible to external temperature changes affecting magnetic field strength characteristics, leading to circuit malfunction. When using Hall sensors to drive inductive loads, please connect freewheeling diodes in parallel across the load terminals; otherwise, transient high-voltage pulses during long-term operation of the inductive load will affect the service life of the Hall sensor. To ensure safety, please check whether the wiring is correct and verify that the voltage is the rated value before powering on.

Seika sensor applications

1) Motor industry: Brushless motors have a series of advantages, including small size, light weight, high efficiency, convenient speed regulation, low maintenance, long service life, and no electromagnetic interference, with annual demand reaching hundreds of millions. In brushless motors, magnetic sensors are used for rotor magnetic pole position sensing and stator armature current commutation. Many magnetic sensors, such as Hall devices, Wiegand devices, and magnetoresistive devices, can be used, but Hall devices are the most widely used. Motor speed detection and control use rotary encoders; optical encoders were previously common. The use of magnetic encoders shows increasing advantages and is gradually replacing optical devices. Magnetic sensors can also be used for motor overload protection (mainly using Hall current sensors) and torque detection. 2) Power electronics technology: Power electronics technology combines power technology and electronic technology, enabling mutual conversion between AC and DC currents, and allowing free regulation of current, voltage, and frequency within required ranges. Using these technologies and products, various special power supplies (such as UPS, high-frequency power supplies, switching power supplies, arc welder inverter power supplies, etc.) and AC variable frequency drives (AC VFDs are used for motor speed control, offering excellent energy-saving effects) can be manufactured. The core of these conversion devices is high-power semiconductor devices. Various current sensors based on magnetic sensors are used to monitor, control, and protect these high-power devices. Hall current sensors have fast response speeds and rely on magnetic field coupling with the controlled circuit without connecting to the main circuit, resulting in low power consumption, strong overload resistance, good linearity, and high reliability. They can serve as overcurrent protection drivers for high-power devices or as feedback devices, becoming a control link in automatic control loops. Using conversion technology can save significant amounts of energy; 95% of electrical energy used abroad is obtained through conversion. Although conversion technology has received high attention domestically, only 5% of electrical energy undergoes this transformation, indicating huge application prospects. This area, which may absorb a large number of current sensors, is another major industrial application field for magnetic sensors. 3) Energy management: Automatic grid monitoring systems need to collect large amounts of data, which, after computer processing, monitors grid operating conditions and performs load distribution adjustment and safety protection. Each control link in the automatic monitoring system can be implemented using current sensors and transformers based on magnetic sensors. Hall current sensors are gradually being applied in grid systems. Watt-hour meters made with Hall devices are shifting from development to practical application; they can automatically bill and display power factor for timely adjustment, ensuring efficient electricity usage. 4) Machine technology and information read/write heads: In addition to magnetic tapes and disks, magnetic information recording devices include magnetic cards, magnetic ink record books, and magnetic records on banknotes, creating huge demand for magnetic information storage and readout sensors. Inductive heads, thin-film magnetoresistive heads, and amorphous heads are widely used. As recording density increases, for example to 100G bytes, heads with higher sensitivity and spatial resolution are required. Giant magnetoresistive heads based on multilayer metal films, amorphous alloy heads made from amorphous alloy wires, and giant magnetoimpedance heads are competing intensely. 5) Automotive industry: Cars use a large number of motors (advanced cars require about 40～60 motors per vehicle, and standard cars have 15, showing a trend toward brushless designs). The extensive use of magnetic sensors in these motors is self-evident. Another area with heavy magnetic sensor usage is the car's ABS system (Anti-lock Braking System), where each car uses an average of 4～6 speed sensors, primarily inductive speed sensors. New types of Hall gear sensors, as well as Wiegand devices, amorphous devices, and magnetoresistive devices, are gradually entering this field. Additionally, speed sensors and igniters for engine ignition timing mainly use inductive sensors. Hall gear sensors and Hall plate switches are already used in some car models. According to Honeywell, by 1996 year 6 month, they had supplied 8000 ten thousand Hall vane switches and 300 ten thousand Hall gear speed sensors to the automotive industry. It is predicted that future cars will adopt more than 30 magnetic sensors similar to Hall sensors. Furthermore, in fields such as industrial automatic control, robotics, office automation, home appliances, and various security systems, in addition to the widespread use of brushless DC motors and AC variable frequency drives, a large number of magnetic temperature controllers are used in devices like refrigerators, air conditioners, and rice cookers. By the mid-80s, the number exceeded hundreds of millions.

Weidou Intelligent Technology specializes in selling German Seika sensors, Seika proximity sensors, Seika distance sensors, Seika vision sensors, Seika displacement sensors, Seika torque sensors, Seika speed sensors, Seika photoelectric sensors, Seika position sensors, Seika angle sensors, Seika tactile sensors, Seika temperature sensors, Seika pressure sensors, Seika flow sensors, Seika level sensors, Seika motion sensors, Seika process sensors. Original German imports. Welcome inquiries and orders.