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Method of Operating an Electromagnetic Actuator for a Print Hammer

IP.com Disclosure Number: IPCOM000051349D
Original Publication Date: 1981-Jan-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 2 page(s) / 62K

Publishing Venue

IBM

Related People

Lansing, SG: AUTHOR [+2]

Abstract

This article describes a method of operating an electromagnetic actuato for a print hammer or the like in which the drive coil and buckout coil of the actuator are operated in a manner to greatly reduce the settle time of the armature.

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Method of Operating an Electromagnetic Actuator for a Print Hammer

This article describes a method of operating an electromagnetic actuato for a print hammer or the like in which the drive coil and buckout coil of the actuator are operated in a manner to greatly reduce the settle time of the armature.

Electromagnetic actuator 10 comprises drive coil 11 and buckout coil 12 on a magnetic core 13. When coil 11 is energized, armature 14 rotates on pivot 15, pushing rod 16 and hammer 17 until armature 14 seats against pole 18 of core
13. Rod 16 and hammer 17 continue in motion to impact the print medium 19 against type 20 moving in front of platen 21. The current to coil 11 is timed to terminate upon armature 14 seating against pole 18. At that time a current pulse is applied to coil 12 for generating a bucking magnetic flux in magnetic core 13. This causes the primary flux generated by coil 11 to decay much more rapidly, thereby greatly reducing the settle time of armature 14.

In Fig. 2, curve 22 is a flux trace produced with coil 11 energized if coil 12 is not energized. In Fig. 3, curve 23 is the flux trace produced when coil 12 is energized at about the same time that coil 11 is turned off with current applied in the opposite direction. With this arrangement, the flux in core 13 can be driven to zero in less than one millisecond.

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