12.1Inverter Application Precautions
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12.1.3 Settings
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Upper Limits
The Digital Operator can be used to set high-speed operation up to a maximum of 400 Hz. Incorrect settings
can be dangerous. Use the maximum frequency setting functions to set upper limits. (The maximum output
frequency is factory-set to 60 Hz.)
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DC Injection Braking
The motor can overheat if the DC injection braking voltage or braking time is set to a large value.
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Acceleration/Deceleration Times
The motor’s acceleration and deceleration times are determined by the torque generated by the motor, the
load torque, and the load’s inertial moment (GD
2
/4). If the stall prevention functions are activated during
accelerationordeceleration,increasetheaccelerationordecelerationtime.Thestallpreventionfunctionswill
increase the acceleration or deceleration time by the amount of time the stall prevention function is active.
To reduce the acceleration or deceleration times, increase the capacity of the motor and Inverter.
12.1.4 Handling
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Wiring Check
The Inverter will be internally damaged if the power supply voltage is applied to output terminal U, V, or W.
Check wring for any mistakes before supplying power. Check all wiring and sequences carefully.
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Magnetic Contactor Installation
Do not start and stop operation frequently with a magnetic contactor installed on the power supply line. Do-
ing so can cause the Inverter to malfunction.
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Setting the Power Supply Voltage Jumper (400 V Class Inverters of 55 kW or
highter)
If the jumper is inserted into a power tap that does not match the actual power supply voltage, the lifetime
of the transformer for the power supply or the wind capacity of the cooling fan may be reduced.
If the jumper is inserted and the voltage setting is too low for the actual power supply, a power surge may
occur on the transformer for the power supply and reduce the lifetime of the transformer.
If the jumper is inserted and the voltage setting is too high for the actual power supply, the wind capacity of
the cooling fan is reduced.
Insert the jumper into the power tap with the voltage setting nearest to the voltage of the actual power supply.
Refer to chapter 4 Trial operation for the procedure.
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Inspections
The internal capacitors in the Inverter require time to discharge after the power supply is turned OFF. Do not
start inspections until the CHARGE indicator goes out.
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Wiring UL/C-UL Inverters
Always use closed-loop connectors when wiring Inverters that meet UL or C-UL standards. Always use the
crimp tool specified by the manufacturer of the closed-loop connectors.
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