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6 Motor and motor control
Take care when measuring the motor control system since all components have a potential difference of
approximately 300V in relation to protective earth and neutral.The components will contain dangerous
voltages when the green LED on the motor control board is on. The motor control system will remain live for
30-60 seconds after cutting the power to the machine and the motor has stopped running.
6.1 Motor control unit
The motor control unit communicates with the program control unit board via a serial (input/output)
interface. With the aid of the motor control unit the program control unit can control not only the
speed of the motor at any given point, but also the acceleration or deceleration rate at which the
motor is to achieve the speed required. The motor control unit constantly feeds information on
current status (both normal status and on any abnormalities arising) back to the program control
unit board.
The motor control unit can also supply data on the different torque and effect of the motor at
constant speed when accelerating and decelaration. These data are used both for calculating the
weight of the load and for detecting any unbalance.
The voltage on the motor control circuit has a potential difference of approx. 300 V in relation to incoming
neutral and earth. Because of this, be careful when measuring. Use unearthed oscilloscopes. If the motor
control unit has a green LED, this will remain lit for as long as there are hazardous voltages present in
components.
Summary of Contents for W555H
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