AC relay with shading coil (red arrow near top) for operating with AC
A shading coil or shading ring (Also called Frager spire or Frager coil) is one or more turns of electrical conductor (usually copper or aluminum) located in the face of the magnet assembly or armature of an alternating current solenoid. The alternating current in the energized primary coil induces an alternating current in the shading coil. This induced current creates an auxiliary magnetic flux which is 90 degrees out of phase from the magnetic flux created by the primary coil.[1]
Frager spire or shading coil's purpose is to provide sizeable phase-shifted magnetic field (in blue) to keep the contactor on when the main coil flux (in red) passes through zero, avoiding unwanted chatter[2] and mechanical destruction of the magnet and power contacts. .
Because of the 90 degree phase difference between the current in the shading coil and the current in the primary coil, the shading coil maintains a magnetic flux and hence a force between the armature and the assembly while the current in the primary coil crosses zero. Without this shading ring, the armature would tend to open each time the main flux goes through zero and create noise, heat and mechanical damages on the magnet faces, so it reduces bouncing or chatter[3] of relay or power contacts.[4]
^"Figure 2. Sketch of the contactor's electromagnet, dimensions in..." ResearchGate.
^"Chegg.com". prod.cheggstudy.prod2.cheggnet.com.
^Riba, J. R.; Espinosa, A. G.; Cusido, J.; Ortega, J. A.; Romeral, L. (2008). "Design of Shading Coils for Minimizing the Contact Bouncing of AC Contactors". 2008 Proceedings of the 54th IEEE Holm Conference on Electrical Contacts. pp. 130–136. doi:10.1109/HOLM.2008.ECP.34. ISBN 978-1-4244-1901-2. S2CID 38248177.
A shadingcoil or shading ring (Also called Frager spire or Frager coil) is one or more turns of electrical conductor (usually copper or aluminum) located...
was split, and had a shadingcoil on one part; the shadingcoils were on the parts that faced each other. Applying AC to the coil created a field that...
with alternating current, a small part of the core is surrounded with a shadingcoil, which slightly delays the magnetic flux in the core. The effect is to...
similar to coil machines and some that look more like “pens”. Coil machines are usually each tuned for a single function, such as for shading, or lining...
; Cusidó, J.; Ortega, J.A.; Romeral, L. (November 2008). Design of ShadingCoils for Minimizing the Contact Bouncing of AC Contactors. Electrical Contacts...
shadingcoil on the pole: 14 is used to maintain contact force throughout the alternating current cycle. Because the air gap between the fixed coil and...
clocks) may have multi-pole permanent magnet external cup rotors, and use shadingcoils to provide starting torque. Telechron clock motors have shaded poles...
HVAC (heating, ventilation and air conditioning), electrical, lighting, shading, access control, security systems, and other interrelated systems. Some...
of alternatives, like passive cooling, evaporative cooling, selective shading, windcatchers, and better thermal insulation. Air conditioning dates back...
attenuation with a loss of image brightness and significant shading to the uniformity. Surface coil sensitivity intensifies problems related to RF attenuation...
shown as transparent red in the figure with darker shading indicating greatest density near the coil pair and extending out to the magnetopause radius...
uniquely wide range of phenotypic plasticity. This climbing action prevents shading by neighbors and allows the vine to grow out of reach of herbivores. The...
outline (although advanced vector systems can provide a limited amount of shading). Text is crudely drawn from short strokes. Refresh vector displays are...
may degrade some media, and other components of the cooler. Therefore, shading is advisable in all circumstances, though the vertical aspect of the pads...
Solar control - A properly designed shading system can effectively contribute to minimizing the solar heat gains. Shading both transparent and opaque surfaces...
Kaieteur News. Retrieved 2 June 2018. Dariusz Heim and Kamil Kieszkowski: Shading Devices Designed to Achieve the Desired Quality of Internal Daylight Environment...
called Japanese arrowroot or Chinese arrowroot, is a group of climbing, coiling, and trailing deciduous perennial vines native to much of East Asia, Southeast...
previous using shape from shading algorithms. Same as the previous, but with lighting homogenized before applying the shape from shading algorithms. Inverse...
spirulina growth is light. When growing in water depths of 12–15 cm, self-shading governs the growth of the individual cell. However, research has shown...
utilize burrows to insulate from extreme heat, the saguaro cactus' self-shading ability, and the native bird - the toco toucan - beak which plays a role...
combining this strategy with an outdoor shading device like shutter, a roof overhang, or an interior shading to block excessive solar radiation from heating...
(right-handed) in coiling. The shell of an adult snail is 16–27 mm in width. The umbilicus is narrow. The color of the shell is brown, shading to white underneath...
polypeptide backbone. α-helices are shown as coiled ribbons or thick tubes, β-sheets as arrows, and non-repetitive coils or loops as lines or thin tubes. The...
(socket) shown on the right. Ground glass surfaces are shown with gray shading. By assembling them in the direction of the arrows, they can be joined...
electromagnetic coils. Another early tattoo machine, with an electromagnetic coil, was patented by Sutherland MacDonald in 1894. The first twin-coil machine,...
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