Hitachi G 12VA, Технические данные и руководство по обслуживанию

Страница: 13 / 40

-10-
(d) Control circuit failure may result in abnormally high rotation speed. Should the control circuit in the
tool malfunction, the rotation speed may increase excessively, thereby rendering continued use of
the tool extremely hazardous. In such case (of abnormally high rotation speed), the operator will hear
abnormal noise from the motor and/or gears. If such a phenomenon occurs, the customer should
immediately shut off the tool, and then bring it to the nearest Hitachi authorized sales outlet or repair
center for inspection and repair.
(5) Kickback protection control
For kickback protection, the microcomputer computes the drop in rotation speed per a specified length
of time when the tool attached to the grinder is placed under a load large enough to immediately stop
the tool's rotation during operation, and issues a command to shut off power to the motor if this
computed drop exceeds a preset drop limit. Conversely, kickback protection control is not actuated if
the computed drop is less than the preset drop limit. In either case, overload protection control may be
actuated several seconds later to stop the motor. Instruct the customer to immediately turn off the main
switch in case kickback protection control is actuated, separate the tool attached to the grinder from the
workpiece, turn on the main switch, wait until the rotation speed increases to normal speed, and then
resume work. Also advise the customer that overload protection control will quickly reactuate even
under a slight load if the customer resumes work before the rotation speed increases to the normal
level.
(6) 0-voltage restart protection control
Instruct the customer to immediately turn off the main switch in case 0-voltage restart protection control
is actuated, separate the tool attached to the grinder from the workpiece, turn on the main switch, wait
until the rotation speed increases to normal speed, and then resume work. Also instruct the customer to
turn off the main switch and not to use this product near a machine that generates electromagnetic
noise, near an extremely strong magnetic field, or under stormy weather conditions with thunder or
lightning because the microcomputer could malfunction due to noise and 0-voltage restart protection
control may not be actuated correctly. Note that 0-voltage restart protection control may not be actuated
in case of momentarily power failure.