Control Techniques Unimotor fm E3, Unimotor fm U3 Cross Reference

Crossover Guide

Unimotor fm E2/U2 to

Unimotor fm E3/U3

Class-leading servo motor performance

Application specics should be reviewed by an Emerson Application Engineer.

Unimotor fm Servo Motors - E2/U2 migration to E3/U3 models

INTRODUCTION

The Unimotor fm servo motor family has recently been redesigned to utilize Emerson Industrial Automation’s latest
manufacturing and component design improvements. This redesign provides improved performance in a shorter length
frame as compared to the previous design.

The following provides information to help identify these design improvements for those times when replacement of the
previous design is necessary. Note that there are 100% mechanical mounting replacements for any existing field installed
models. All previous order code information regarding bolt circle diameter, pilot diameter and shaft diameter are available
in the new design’s order string.

You will also see in the following information that there are higher performance specifications listed for most frames and
lengths. Electrical parameters like, Kt (torque constant) and Ke (voltage constant) remained the same for the new models.
This will allow for direct replacement into existing applications with no need to change motor parameters to maintain the
existing performance levels. Only instances where increased motor performance levels are desired would changes to drive
parameters be needed.

Unimotor fm E2/U2 Unimotor fm E3/U3

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The Unimotor fm E3/U3 servo motors also have

a raised EMERSON logo on the back cover.