Crane Control Equipments




Rotary Limit Switch


Rotary Limit Switch

We have come up as one of the major Manufacturers, Exporters and Suppliers of Rotary Limit Switches in New Delhi. The high quality range of the v, offered by us, is known for its quality as well as long service life. The Rotary Limit Switches can be availed at the best prices and the timely delivery is ensured.

Features :
  • Used on control/power circuit of reversing drives so as to limit their rotation/movement within a predetermined position
  • Function is to stop the mechanism of drive at the extreme clockwise/anticlockwise position
  • Particularly suited for use on reversing drives such as electric hoists, winches, over head cranes, traverses etc
  • Contacts rated for 40 amps at 500 Volts A.C.
  • Can be provided with 2NC contacts or (2 No + 2NC) contacts as per the requirement
  • Geared type Rotary Limit Switch basically consists of heavy duty worm gear drive with a ratio of 48:1, 60:1 or 96:1
  • Rotary Limit Switches having Gear Ration of 1:50 1:200 and 1:500 available
  • Made in IP-41 as well as in IP-54 enclosure
  • In case of IP 41 enclosure the housing is made from suitably reinforced sheet
  • In case of IP-54, the cover is of cast aluminum
  • Base and cover have machined surface to protect the limit switch against dust.
  • Cam shaft extends from behind the gear into the sheet steel housing and accommodates the cams
  • 2 or 4 cams are used depending upon whether the switch is of 2 contacts or 4 contacts operation
  • Contacts have maximum continuous current capacity of 40 amps AC
  • Contact tips made of high grade Silver Cadmium Oxide alloy
  • When used for Series operation [up to 40 Amps maximum], the contacts are suitable for 720 operations per hour
  • In case of Shunt operation [for Control Circuit], the contacts are suitable for 1200 operation per hour
  • Same contacts can be used in series as well as in shunt configurations
  • Switching capacity of the contacts when used for shunt operation is 15 amps at 400 Volts, AC on highly inductive load and 2.5 amps at 220 Volts DC
  • Switching capacities in fact are far in excess of what is actually required in practice and hence replacement of contacts for shunt may not be necessary for a long time
  • Body of the contacts is made of high grade melamine which is specifically suited for heavy duty operation
  • Material is non-tracking and is capable of with standing heavy arcing

Working :
  • The mechanism or the drive coupled to the limit switch actuates the contacts through the worm gear drive and the cams.
  • When the mechanism or the drive approaches the pre determined position, the cam strikes the contact finger of the corresponding contact which in normal condition is in a closed position
  • This immediately opens the contacts and the circuit is broken there by disconnecting the respective motor from the supply and resulting in the stoppage of the drive or mechanism.
  • The actuator or cam is provided with a maximum follow-through angle of 60 degrees there by ensuring that the normally closed contact, which has been opened by the actuator/cam, shall remain in the open position for at least 7 full additional revolutions of the input shaft.
  • This provision is adequate for most of the reversing drives where the mechanism or drive comes to a complete stop with in 1/5th of a revolution of the input shaft of the limit switch.