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FANUC LTD
DESCRIPTION DESIGN DATE
EDIT
FANUC SERVO AMPLIFIER
β
iSV 20/20 DESCRIPTIONS
B-65322EN/02-03
10. Power failure detecting function
The power failure detect function aiming at the gravity axis fall prevention at the time of a
power failure was occurred.
Please refer to the section [11.5] for connection details.
In case of using this function, please add an uninterruptible power supply (UPS) etc. to be
able to maintain the control source (DC 24V) of CNC and amplifier after a power failure
occurs until mechanical brake operates.
Specification
2-axes amplifier
βiSV output a power failure detect signal from a connector CX36, when
power failure is occurred.
The drop of three-phase circuit AC voltage inputted into the connector “CZ4” of 2-axes
amplifier β
iSV is detected.
CZ4 input voltage range: 0 V-AC240V+10% 3φ 50Hz/60Hz±2Hz
CZ4 power failure detect voltage: AC165V±10V
Detection delay time is established so that it may not react sensitively to instantaneous
power failure.
Detection delay time: 8msec~17msec
(Note)
The detect condition is simultaneous three-phase circuit AC voltage drop.
Therefore, it may be unable to detect a power failure correctly on following conditions.
1. Power failure (phase interruption) as only one phase drop.
2. Power failure occurred at the time of motor acceleration. (Please see below.)
3. The amplifier is necessary to operate normally at instantaneous power failure for
3msec or less and for this terms the power failure detect signal is not detected.
β
i
SV Input Voltage
Power failure
detect signal
Motor speed
DC link voltage
cceleration
8msec ~ 17msec
Low voltage alarm
Of DC link
power failure detecting signal is outputted
from
βi
SV behind time 8msec~17msec afte
power failure occur. When the output powe
of motor is large by acceleration, DC link
voltage falls rapidly. So, even if power failure
is detected, DC link low voltage alarm may be
occurred.
larm occurred