Peripheral Devices - YASKAWA CR700 Manual

Peripheral Devices

■ Installing a Ground Fault Interrupter or an MCCB
･ Be sure to install an MCCB or an ELCB that is
recommended by Yaskawa at the power supply side of
the drive to protect internal circuitry.
･ The type of MCCB is selected depending on the power
supply power factor ( power supply voltage, output
frequency, load characteristics, etc. ) . Sometimes a
fairly large MCCB may be required due to the affects of
harmonic current on operating characteristics. If you
do not use a recommended ELCB, use one fi tted for
harmonic suppression measures and designed
specifi cally for drives. A malfunction may occur due to
high - frequency leakage current, so the rated current of
the ELCB must be 30 mA or higher per drive unit. If a
malfunction occurs in an ELCB without any
countermeasures, reduce the carrier frequency of the
drive, replace the ELCB with one that has
countermeasures against high frequency, or use an
ELCB which has a rated current of 200 mA or higher
per drive unit.
Select an MCCB or an ELCB with a rated capacity
greater than the short - circuit current for the power
supply. For a fairly large power supply transformer, a
fuse can be added to the ELCB or MCCB in order to
handle the short - circuit current level.
■ Magnetic Contactor for Input Power
Use a magnetic contactor ( MC ) to ensure that power to
the drive can be completely shut off when necessary. The
MC should be wired so that it opens when a fault output
terminal is triggered.
Even though an MC is designed to switch to a momentary
power loss, frequent MC use can damage other
components.
Avoid switching the MC more than once every 30
minutes. The MC will not be activated after a momentary
power loss if using the LCD keypad to run the drive. This
is because the drive is unable to restart automatically
when set for LOCAL.
Although the drive can be stopped by using an MC
installed on the power supply side, the drive cannot stop
the motor in a controlled fashion, and it will simply coast
to stop. If a braking resistor or dynamic braking unit has
been installed, be sure to set up a sequence that opens
the MC with a thermal protector switch connected to the
braking resistor device.
■ Magnetic Contactor for Motor
As a general principle, the user should avoid opening and
closing the magnetic contactor between the motor and
the drive during run. Doing so can cause high peak
currents and overcurrent faults. If magnetic contactors are
used to bypass the drive by connecting the motor to the
power supply directly, make sure to close the bypass only
after the drive is stopped and fully disconnected from the
motor.
Motor Thermal Over Load Relay Installation
■
Although the drive comes with built in electrothermal
protection to prevent damage from overheat, a thermal
relay should be connected between the drive and each
motor if running several motors from the same drive.
For a multi - pole motor or some other type of nonstandard
motor, Yaskawa recommends using an external thermal
relay appropriate for the motor. Be sure to disable the
motor protection selection parameter ( L 1 - 01
the thermal relay or thermal protection value to 1 . 1 times
the motor rated current listed on the motor nameplate.
When long motor cables and high carrier frequency are
used, nuisance tripping of the thermal relay may occur
due to increased leakage current. Therefore, reduce the
carrier frequency or increase the tripping level of the
thermal overload relay.
Improving the Power Factor
■
Install a DC reactor, AC reactor, or Power Regenerative
Converter D 1000 to the drive input side to improve the
power factor. The DC reactor is built in for models of
catalog codes CR 70
□
and above.
Refrain from using a capacitor or surge absorber on the
output side as a way of improving the power factor,
because high - frequency contents on the output side can
lead to damage from overheat. This can also lead to
problems with overcurrent.
Radio Frequency Interference
■
Drive output contains high - frequency contents that can
affect the performance of surrounding electronic
instruments such as an AM radio. These problems can be
prevented by installing a noise fi lter, as well as by using a
properly grounded metal conduit to separate wiring
between the drive and motor.
YASKAWA AC Drive CR700 Catalog
= 0
) , and set
2088 and above, CR 70 4045
□
YASKAWA
KAEP C710617 24
｜ ｜
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