E6581158
A-16
1
1.4
Notes on the application
1.4.1 Motors
When the VF-S11 and the motor are used in conjunction, pay attention to the following items.
Warning
Mandatory
Use an inverter that conforms to the specifications of power supply and three-phase induction motor be-
ing used. If the inverter being used does not conform to those specifications, not only will the three-phase
induction motor not rotate correctly, but it may cause serious accidents through overheating and fire.
Comparisons with commercial power operation.
The VF-S11 Inverter employs the sinusoidal PWM system. However, the output voltage and output cur-
rent do not assume a precise sine wave, they have a distorted wave that is close to sinusoidal wave-
form. This is why compared to operation with a commercial power there will be a slight increase in mo-
tor temperature, noise and vibration.
Operation in the low-speed area
When running continuously at low speed in conjunction with a general purpose motor, there may be a
decline in that motor's cooling effect. If this happens, operate with the output decreased from rated
load.
To carry out low-speed operation continuously at the rated torque, we recommend to use a “VF motor”
or a “Gold motor” designed for use with an inverter. When operating in conjunction with a “VF motor”,
you must change the inverter's motor overload protection level to VF motor use (
QNO
).
Adjusting the overload protection level
The VF-S11 Inverter protects against overloads with its overload detection circuits (electronic thermal).
The electronic thermal's reference current is set to the inverter's rated current, so that it must be ad-
justed in line with the rated current of the general purpose motor being used in combination.
High speed operation at and above 60Hz
Operating at frequencies greater than 60Hz will increase noise and vibration. There is also a possibility
that such operation will exceed the motor's mechanical strength limits and the bearing limits so that you
should inquire to the motor's manufacturer about such operation.
Method of lubricating load mechanisms
Operating an oil-lubricated reduction gear and gear motor in the low-speed areas will worsen the lubri-
cating effect. Check with the manufacturer of the reduction gear to find out about operable gearing
area.