Reference Materials; Feedback System - Hitachi DS 14DAL Technical Data And Service Manual

9. REFERENCE MATERIALS

9-1. Feedback System

The Model DS 14DAL has the variable speed switch equipped
with the feedback system. This feedback system ensures a
sufficiently large torque even in the variable speed range.
For example, when operating the Model DS 14DAL at a
speed about 80% of the full speed, the maximum torque is
about 95% of that at a full speed (curve "A"). Even when the
Model DS 14DAL is operated at a speed about 30% of the full
speed, the maximum torque does not decrease under about
65% of that at a full speed (curve "B") to ensure a sufficiently
large torque at a low speed.
Torque (%)
Besides, the braking function allows the driver unit to stop
Schematic diagram of the feedback system
rotation immediately when the trigger switch is released,
which is a convenient feature for continuous screw tightening or drilling works. The step-less variable speed
mechanism controls the speed depending on the depressed amount of the trigger switch within the range from 0
to 350 cycles per minute for the low speed mode and from 0 to 1,200 cycles per minute for the high speed mode.
Thanks to this mechanism, positioning is easily done for screw tightening and drilling works.
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