Tractor Motor - Printronix L5535 Maintenance Manual

Tractor Motor

Since this motor moves the fanfold paper forward and backward to determine
the print position, it is necessary to control not only its rotating speed but also
its rotation direction and amount. Therefore, the encoder for this motor has
three sensing elements (consisting of a light emitter and receptor) as shown
below. The pulse trains (phases A and B) detected by sensing elements A
and B determine the rotating speed and direction. The pulse trains (phase Z)
detected by sensing element Z determine the rotation amount.
Tractor Motor Encoder (within Motor)
Sensing Element B
Forward Tractor Rotation
Phase A
Phase B
Phase Z
Reverse Tractor Rotation
Phase A
Phase B
Phase Z
Four hundred pulses are generated during one encoder revolution for phases
A and B (the interval between two neighboring broken lines shown above
Sensing Element A
Motor Rotation Control
Sensing Element Z
II–147