Brother Industries SUPER ACE+e, Руководство по обслуживанию

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5. MAIN MOTOR CONTROL
The main motor for the sewing machine is required to smoothly change from low speed to high speed without any
fluctuations due to load or temperature changes. To fully comply with this requirement, this model adopts PWM
control using FET.
6. PATTERN GENERATOR
For conventional sewing machines, the pattern was generated by rocking the needle bar and the feed regulator
by means of a pattern cam onto which the pattern data had been mechanically engraved. In contrast to this, this
model stores the data electronically in memory and uses a feed pulse motor and a zigzag pulse motor to directly
rock the needle bar and the feed regulator to generate the pattern. In addition, the pulse motors must move the
position of the needle while the needle is raised and stop it in the correct position (and similarly, they must move
the position of the feed regulator while the needle is lowered). Thus, highly-precise positioning and a fast
response speed are required. Because of this, the feed pulse motor and a zigzag pulse motor were adopted, and
a simple open-loop structure circuit was employed.
Block diagram of pattern generator control
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