Fisher & Paykel Smartload DEGX1, Service Manual

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3.5.9 Drum Control.
The drum is coupled to a three phase induction motor
by way of a pulley on the motor shaft, which drives
via a “V” belt and belt tensioner system. The motor
control module controls the motor by generating the
three phases from a high voltage rectified DC rail.
When tumble drying, the drum is tumbled at 47 RPM,
during opening and closing at 5 RPM, and at other
speeds as required and requested from the sensor
module. Feedback on speed is via the drum
tachometer signal, which comes via the sensor
module.
When drying, the drum rotates in the door closing
direction for 4 minutes, after which it coasts to stop
and reverses for 40 seconds, then coasts to stop
before repeating the reversing throughout the drying
and cooling cycle. The reversing of the drum
direction reduces tangling.
During Wrinkle Guard the drum rotates in one direction for 30 seconds, then stops for 5
minutes without opening the drum door, after which it goes in the opposite direction for 30
seconds, then pauses again before turning off. If the user does not remove the clothes
load, the cycle is repeated 255 times, which take approximately 23 hours.
The drum tachometer uses pressed “dimples”, formed directly into the drum end outlet,
spaced every 2 degrees to provide positioning information while also providing speed data.
There is a 15 degree “gap” to provide the reference for absolute position. An infrared
diode and optical receiving transistor provide the reading of the “dimples.” The digital
signal is output to the motor control module, which uses the signal for speed controlling the
drum. The drum position is monitored by the sensor module, which uses the position for
both speed commands and drum door actuator control.
3.5.10 Drum Door Control
The drum door is opened and closed by the door
grabber, which is positioned by an actuator driven
by a small DC brush motor.
A mechanical interlock prohibits the drum door from
latching closed if garments get caught in the door
opening. With the door unable to close, the drum
will stall, which will be sensed by the motor control
module and corrective action will occur.
After Start/Pause is pressed when the dryer is
waiting with the drum door open:
1. The lid will lock.
2. The sensor module assumes the drum door is open at “Home” and rotates the drum at
5 RPM in the drum door close direction. If it is “Home” and the grabber lowered, the
door will close at 78 degrees away from “Home”.
Note : If the door is closed and the
grabber lowered, the drum will simply rotate with a slight rubbing noise of the grabber
on the drum.
Belt Tensioner
System
Belt
Three Phase
Motor
Reference
Point
Dimples