Appendix A
Chapter 7
D Vibration
The 3G3EV series employs high carrier PWM control to reduce motor vibration. When
the motor is operated with this Inverter, motor vibration is almost the same as when op-
erated with a commercial power supply.
However, motor vibration may become greater in the following cases:
• Resonance with the natural frequency of mechanical system
Take special care when a machine that has been operated at a constant speed is to
be operated in variable speed mode. If resonance occurs, install vibration-proof rub-
ber on the motor base.
• Imbalanced rotor
Take special care when the motor is operated at a high speed (60 Hz or more).
D Noise
Noise is almost the same as when the motor is operated with a commercial power sup-
ply. However, motor noise becomes louder when the motor is operated at a speed high-
er than the rated speed (60 Hz).
H Using Inverter for Special Motors
D Pole-changing Motor
The rated amperage of pole-changing motors differs from that of standard motors.
Select, therefore, an appropriate Inverter according to the maximum amperage of the
motor to be used. Before changing the number of poles, always make sure that the mo-
tor has stopped. Otherwise, the overvoltage protection or overcurrent protection mech-
anism will be actuated, resulting in an error.
D Submersible Motor
The rated amperage of submersible motors is higher than that of standard motors.
Therefore, always select an Inverter by checking its rated amperage. When the dis-
tance between the motor and the Inverter is long, use a cable thick enough to prevent
motor torque reduction.
D Explosion-proof Motor
When an explosion-proof motor or increased safety type motor is to be used, it must be
subject to an explosion-proof test in conjunction with the Inverter. This is also applicable
when an existing explosion-proof motor is to be operated with the Inverter. However,
since the Inverter itself is not explosion-proof, always install it in a safe place.
7-3
OMRON [ OMRON ELECTRONICS LLC ]
