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# Motor Internal Resistance Value Correction

IP.com Disclosure Number: IPCOM000039360D
Original Publication Date: 1987-May-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 3 page(s) / 76K

IBM

## Related People

Cavill, BR: AUTHOR [+2]

## Abstract

This article describes a technique to provide correction of the motor drive component in an electric motor related to the motor internal resistance to account for velocity variations due to motor temperature changes. The drive values calculated for driving a printer are determined by adding three components of the drive value together. These three components of the drive are the frictional effects term, the Emf term which provides the acceleration, and the internal resistance term which is applied when accelerating and decelerating and represents the voltage required to overcome the internal losses in the motor. It has been determined that this value is constant for a motor/system configuration, but the value varies as the temperature in the motor increases.

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Motor Internal Resistance Value Correction

This article describes a technique to provide correction of the motor drive component in an electric motor related to the motor internal resistance to account for velocity variations due to motor temperature changes. The drive values calculated for driving a printer are determined by adding three components of the drive value together. These three components of the drive are the frictional effects term, the Emf term which provides the acceleration, and the internal resistance term which is applied when accelerating and decelerating and represents the voltage required to overcome the internal losses in the motor. It has been determined that this value is constant for a motor/system configuration, but the value varies as the temperature in the motor increases. By correcting this value, the velocity does not vary with temperature. Fig. 1 is a diagram illustrating the motor drive value calculations vs. IR value (IRVAL).

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When the printer is first turned on, the machine contains a read- only storage (ROS) value which is pre-calculated to represent the motor and average loading characteristics of the machine. This value is moved into a register labeled IRVAL where it remains. If the machine is a color machine, this value is modified to the value required for a color machine by a command from an Intel 80188 mechanism control processor. This value is used whenever the machine is to be accelerated or decelerated and is used when calculating the motor voltages required. The IRVAL value is part of the initial drive applied to the motor, and remains until acceleration is completed. If the IRVAL value is decreased, the initial drive voltage is decreased and reduces the total drive applied by one bit for each time the drive is outputted. Also, the time the drive is applied by the incremental time between each motor step is reduced. A similar effect of increasing the drive value and acceleration time is present if the...