page_title: Shading coil
hierarchical_section_title: Shading coil
caption_attribution_description: English: Relais with shading coil (arrow head) for operating with AC Deutsch: Spaltpolrelais (Pfeil: Kurzschlusswindung) für Betätigung mit 42V/50Hz Wechselspannung
context_page_description: A shading coil or shading ring is a single turn of electrical conductor located in the face of the magnet assembly or armature. The main alternating magnetic flux induces currents in the Frager coil. So, these induced currents create an auxiliary magnetic flux. This auxiliary flux is out of phase from the main flux.
  The property of property allows the armature sealed-in when the main flux falls to 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
context_section_description: A shading coil or shading ring (Also called Frager spire or Frager coil) is a single (or a few) turn of electrical conductor (usually copper or aluminum) located in the face of the magnet assembly or armature. The main alternating magnetic flux induces currents in the Frager coil. So, these induced currents create an auxiliary magnetic flux. This auxiliary flux is out of phase from the main flux. 
  The property of  property allows the armature sealed-in when the main flux falls to zero (e. 100 (or 120) times / second with 50 (or 60) cycles AC). 
  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 (e.g. reducing the bouncing of relay or power contacts and the chatter)
caption: AC relay with shading coil (arrow head) for operating with AC
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