Frequently Asked Questions (FAQ)Frequently asked questions about Inverters


QIt is OK to install the inverter unit by putting it on its side or sideways?

Please install the the inverter unit at the upright position and then use. direction.
When it is installed in other position (other than upright position) , it reduces the cooling capability againt the heating radiation from the inverter. As such, it can not satisfy the specifications. Please refer to the manual of each product for installation and handling of the inverter unit.

QIs it OK to select the inverter from the motor capacity described in the specification table in the catalog?

The motors described in the specification table in the catalog indicate cases for our standard 4-pole cage type induction motor. When you select the inverter, please do so by considering the rated current of the motor, the overload capacity of the inverter, etc.

QDo you have a single phase input type inverter?

Currently, we don't have a single phase input type inverter.

QWhat is an inverter?

It primarily means a device that converts DC to AC. By making a system combining with converters that convert DC to AC, it is also collectively called "an inverter". This is a device to control the the speed of an AC electric motor.

QWhat are PWM and PAM?

PWM is an abbreviation of Pulse Width Modulation, and PAM is an abbreviation of Pulse Amplitude Modulation. Both of them indicate a system that converts inverter DC to AC.

QCan a standard motor be driven by the inverter?

The standard motor drives an external fan by its rotation for cooling. Because of that, the cooling ability deteriorates when the rotation speed decreases. Therefore, the motor will become overheated when it is used without reducing the load. It is thus necessary to reduce the load with low speed or to adopt a special motor in which the speed can be varied.

QWhat is the difference between harmonics and high frequency?

"Harmonics" means a wave having a component of an integer multiple of a fundamental wave (50 Hz or 60 Hz). On the other hand, a high frequency wave is a wave with its own high frequency value. (A higher order harmonic wave can be a high frequency wave.) Generally references to noise mostly indicate this high frequency wave.

QWe would like to save energy. Can we save energy if we use an inverter?

Energy will not be saved when the inverter is operated at the same rotation speed as that of an inverter driven by the grid power. When the inverter is operated by lowering the rotation speed to match the loaded condition, the driving power decreases and energy will be saved.

QThe distance between the inverter and the motor is large. Will this become a problem?

When the distance between the inverter and the motor is large, the torque of the motor decreases due to voltage drop of the wiring. It is necessary to design the rated voltage of the motor by considering the cable voltage drop or to make the diameter of the cable larger so that the voltage drop can be ignored. Because the surge voltage becomes high in motor terminals with the 400 V series, insulation deterioration of the motor may occur. It is necessary to enhance the insulation of the motor or to install a filter that suppresses the surge voltage in the inverter side.

QCan we install an electromagnetic contactor between the inverter and the motor?

When an electromagnetic contactor is installed in the output of the inverter, please do not turn on and off during driving. When the electromagnetic contactor is operated during driving, a large current flows, and it causes the inverter to fail.

QWe heard that noise will be generated when the inverter is used. What kind of effects are there?

When the inverter is operated, there may be adverse effects such as "AM radio or a telephone is disturbed by noise", "malfunction occurs in adjacent switches, pressure sensors, etc." The types of primary noise are as follows.
●Conductive noise: noise generated in the inverter and transmitted through a conductor
●Induction noise: noise induced from an input-output wire to a wire of the peripheral device
●Radiation noise: noise emitted into air by the input-output wire becoming an antenna
There are noise countermeasures such as "separating the main circuit line and the control line", "shielding the wire", "performing appropriate grounding construction and grounding wiring", "performing noise countermeasures in the inverter side", and "performing noise countermeasures in the affected equipment side."