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High Efficiency Coil Design

IP.com Disclosure Number: IPCOM000080737D
Original Publication Date: 1974-Feb-01
Included in the Prior Art Database: 2005-Feb-27
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Burns, RC: AUTHOR [+3]

Abstract

Previous coil designs for electromagnetic devices such as print hammers have utilized an optimum design based on the minimum seal or flight time, as derived from the curve of N/2/ over R(T) vs flight time, shown in Fig. 1.

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High Efficiency Coil Design

Previous coil designs for electromagnetic devices such as print hammers have utilized an optimum design based on the minimum seal or flight time, as derived from the curve of N/2/ over R(T) vs flight time, shown in Fig. 1.

Other characteristics for print hammers such as impact velocity and flight time variation due to heating are important, in addition to minimum flight time. Tests show that minimum flight time does not result in maximum velocity and yet the hammer velocity determines the print energy and the print momentum, which determine the quality of printing for a fixed hammer design.

As shown in Fig. 2 the maximum velocity is not attained with the minimum flight time design. By utilizing a coil design in which 1< Proposed turns N over Optimum Design turns No <2 or more specifically approx.= 1.6, the maxim velocity is attained. In addition, the flight time variation due to heating will be minimized.

Accordingly, as the proposed design has more turns its current rise is slower. The slower current rise results in a smaller integral i dt for the proposed design, although the pulse duration is slightly longer. Although the integral i dt of the proposed design is less, the N integral i dt, which produces the magnetic force, of the proposed design is greater due to the increased turns. This applies whether the designs are cold or hot.

When the coils of either design heat up, the current rise is faster due to the increased resistance (T...