China
Africa
Explore chapters and articles related to this topic
Relays and Contactors
Published in Joseph E. Fleckenstein, Three-Phase Electrical Power, 2017
Reed relays function much as an electromechanical relay. A reed relay has a coil and a set of contacts that are shifted from one position to another when the coil is energized. In its most simple form, a reed relay consists of two ferromagnetic strips, or reeds, that are partly sealed within a glass capsule. A design of a single pole, NO reed relay is represented in Figure 12.11. A portion of each reed extends outside the capsule so that electrical connections may be made to that part of the reeds external to the capsule. Portions of the reeds within the capsule that act as contacts are usually plated, sometimes with gold. An electrical coil surrounds the glass tube. When the coil of a NO design is de-energized, there is a gap between the two reeds and the contacts are open. When voltage is applied to the coil a magnetic field is generated, drawing the reeds together and establishing contact closure. When the coil is de-energized, the reeds separate, opening the circuit. Usually, the capsule is either evacuated or charged with an inert gas to prolong contact life. The reeds of a reed relay are hermetically sealed, and for this reason, the contacts are impervious to contaminants, as dust or deleterious gases. Because of the hermetic design, some models of reed relays are approved for use in environments containing explosive gases or explosive dusts. The coils of reed relays accept only dc voltage. Designs of reed relays are available in NO, NC, and double pole configurations. Some models are also available as latching relays. Reed relays respond more quickly than electromechanical relays and typically respond in approximately 1 ms. Most reed relays are encapsulated and intended for mounting on circuit boards.
Distribution of audio signals
Published in Michael Talbot-Smith, Audio Engineer's Reference Book, 2013
David M. Davidson, Bev Marks, Francis Rumsey
Reed relays were the next family of electronic- chanical switch. A reed relay is a magnetic spring contact sealed in a glass envelope to provide a dust- and corrosion-free environment for the contact. A number of these contacts are then enclosed in the centre of a coil and, when the coil is energized, the magnetic contact springs close. Arrays of relays are arranged to form a switching matrix. The advantage of the reed relay is its speed of operation, which at around 1 ms is suitable for electronic control. Reed relay exchanges are nearly all under electronic control of some form.
Reed Switches
Published in Paul G. Slade, Electrical Contacts, 2017
A reed relay is an electromagnetic relay consisting of a reed switch and a driving coil around it or by using a permanent magnet as shown in Figures 11.2 and 11.3. The driving coil or magnet activates switching. There are many kinds of reed relays according to what they are to be applied for. Reed relays have the features described below. They have excellent resistance to environment. Since the contacts are hermetically sealed in a glass tube, they are free from the influence of the surrounding atmosphere. An explosion-proof structure is employed.They have excellent operating characteristics. The operating time, bounce time, and release time are short (see Figure 11.23). Although they vary, depending on the model, the operate time and bounce time are 0.5 ms maximum and the departure time is 0.2 ms maximum [31]. These are one tenth or less than those for mechanical relays.Their input and output are completely isolated from each other electrically.They are miniature and lightweight. The trend of reducing the size of devices and equipment causes reed relays to be miniaturized further. This trend is particularly noticeable with reed relays in ATEs (LSI testers and board testers), which use many reed relays. At present, miniature reed relays measure only 15 mm × 5 mm × 5 mm.They have high sensitivity. Reed relays can control a large current and large voltage on the output side with a small input current of several to several tens of milliamperes.
Performance Analysis of Solar PV system using Customize wireless data acquisition system and novel cleaning technique
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2022
Vinay Gupta, Madhu Sharma, Rupendra Pachauri, K N Dinesh Babu
In the event of a hailstorm, the rain sensor is triggered by raindrops, which activates the relay, which rotates the motor in such a manner that all PV panels come under the protective sheet. In this way, the proposed system protects the solar PV panels from hail. There are reed relay switches on both ends of the track-rail system. When all the PV panels are completely covered and uncovered, they disconnect the relay modules and turn off the motor. The front and rear views of the proposed self-cleaning PV sliding mechanism are shown in Figures 2 and 3. Table 4 shows the different parts of the proposed self-cleaning technique. Table 5 shows the specifications of solar panels used in the experiment at standard testing conditions