Ulvac UTM3400 Series, Instruction Manual

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6.5 Variable Speed Operation
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6
6.5
Variable Speed Operation
CAUTION
When using the variable speed function to change the pump rotation rate, use a rotation rate
that does not cause resonance with other devices installed at the site.
6.5.1 O
utline
(1) The rotational speed settings function sets the rotational speed by selecting between the
NORMAL speed mode or LOW SPEED mode.
(2) Select the NORMAL mode or LOW SPEED mode by REMOTE operation using the
remote-control connector "LOW SPEED" signal input. (Refer to Table 6-4)
(3) The NORMAL mode or LOW SPEED mode selection can be made before or after start-up.
(4) Set the low speed value between 25 % and 100 % of the rated speed in 0.1 % increments,
using the serial communications interface.
(5) The low speed value can be set while the pump is rotating in the LOW SPEED mode. The
pump then accelerates or decelerates to the new set value and maintains the set speed.
(6) The time required for the speed to change is the same as the time for normal acceleration
or deceleration.
For example, if the low speed value is set to 80 % and the LOW SPEED mode is selected
during normal rotation, the time for the speed to drop to 80 % is approximately one-fifth the
time required to stop from rated speed.