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Controlled Lead Angle Advance Circuit for Stepping Motors

IP.com Disclosure Number: IPCOM000074331D
Original Publication Date: 1971-Apr-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 2 page(s) / 39K

Publishing Venue

IBM

Related People

Abraham, DG: AUTHOR [+2]

Abstract

This circuit provides different acceleration and slewing rates of a stepping motor by controlling the advance rate and final lead angle. This function is accomplished by controlling the build-up rate of capacitor C1 which in turn controls the charging rate of the capacitor C2. increasing the charging rate of C2 causes progressively earlier output from the Schmitt trigger thus effectively advancing the lead angle.

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Controlled Lead Angle Advance Circuit for Stepping Motors

This circuit provides different acceleration and slewing rates of a stepping motor by controlling the advance rate and final lead angle. This function is accomplished by controlling the build-up rate of capacitor C1 which in turn controls the charging rate of the capacitor C2. increasing the charging rate of C2 causes progressively earlier output from the Schmitt trigger thus effectively advancing the lead angle.

With the stop Latch going off, T5 turns off allowing X1 to be charged by T1. The first negative feedback transition after the start signal starts the single-shot SS which in turn turns off T3. With T3 off, T1 conducts allowing C1 to charge at a rate determined by VB1 and R3 plus adjustable resistance RE for the duration of the single-shot. The C1 capacitor voltage provides a reference for the transistor T2 as shown at 1 in the timing chart. Capacitor C2 charging rate which is dependent upon VB2 and R8 provides a voltage ramp II which is fed to the Schmitt trigger to provide output A to the OR Gate. An inverted single-shot signal turns on T4 which provides a discharge path for C2. With the stop latch turned on, the advance signal disappears due to the clamping of C1.

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