Inverter Questions and Answers

  1. I want to use the inverter right away.
  2. Using the inverter generates noise that causes other devices to malfunction.
  3. What is the life expectancy of an inverter?
  4. How does an inverter operate?
  5. I would like to make greater use of inverters.

I want to use the inverter right away.

The SAMCO-e inverters feature an input terminal board on the top and an output terminal board on the bottom. Wiring is done by simply connecting the power supply wiring to the top terminal board and the wiring to the motor to the bottom terminal board. When this is done, motor driving is simply achieved by pressing theDRIVEkey on the operation panel and turning the frequency setting dial to set the desired frequency.

Basic inverter wiring diagram

Using the inverter generates noise that causes other devices to malfunction.

Due tothe control operation principle, the inverter generates noise that affects other devices. This noise can be divided into conduction, inductance, and radiation. Countermeasures must be implemented according to the type of influence exerted. In order to reduce the influence of such noise, it is necessary to connect an AC reactor, a DC reactor, or a noise filter; provide shielding inside the metal pipes used for wiring; and/or replace control lines with shielded cable. Contact Sanken Electric for details.

Conduction noise:
This is noise generated inside the inverter that travels through conductors such as wiring and influences peripheral devices.
Inductance noise:
This is noise induced by electromagnetic induction or electrostatic induction when the wiring of peripheral devices and signal wires are placed near the wiring on the input side and the output side of an inverter in which noise current flows.
Radiation noise:
This type of noise occurs when the noise generated inside the inverter is radiated into the atmosphere by the wiring on the input side and output side, which acts as an antenna, affecting peripheral devices.
What is the life expectancy of an inverter?
Part Name Conditions Design Life
Cooling fan Generally, inverters should be checked every 10,000 to 35,000 hours (normally 2 to 4 years under continuous operation) and replacement should be made after inspection shows the necessity for doing so.
Main smoothing electrolytic capacitor
  1. Average annual ambient temperature of inverter: 35°C
  2. Operating load factor: 80%, utilization rate: 12 hours/day, 365 days/year
  3. No top cover set on inverter
Under the temperature condition described on the left, the life expectancy estimated by Sanken Electric is about 10 years.
Smoothing electrolytic capacitor on board
Maintenance inspections

[Recommended periodic inspection]

While the above-listed life figures estimated by Sanken Electric generally apply, we recommend periodic inspection of inverters, checking the indicated inspection items.

Moreover, a trend (known as "Arrhenius Law"*) related to the ambient temperature exists for the aluminum electrolytic capacitors used inside the inverter, which determines the life expectancy of inverters, which are easily influenced by the ambient temperature. If an inverter is used in a high-temperature environment, it is necessary to replace the aluminum electrolytic capacitors inside that inverter within the standard replacement period, in order to ensure long use of the inverter.

* Arrhenius Law (doubling for every 10°C)
When the ambient temperature increases by 10°C, the life expectancy decreases by half, and when the ambient temperature declines by 10°C, the life doubles.

Q4. How does an inverter operate?

The inverter converts the input AC power supply into DC power supply via a rectifying circuit. Since a motor's speed of rotation cannot be controlled with a DC current, the DC current is converted into AC by a pulse width modulation (PWM) control inverter. This AC current is a pulse called a square wave, and control is performed to obtain the optimum pulse count (which depends on the carrier frequency) and pulse width for output.

The relationship between the voltage and frequency at this time is expressed by a V/F pattern.
The relationship between the motor's rotation speed and the inverter's output frequency can be expressed with the following equation.


I would like to make greater use of inverters.

We offer optimum solutions, including specialized inverters, through customized functions that are available by upgrading to the vm05 series. We welcome inquiries about your problems and requirements.

SAMCO-vm05 Customized inverter Device

  • Control devices customized for specific applications
    We offer dedicated inverters by optimizing software for the customer's desires, specifications, and usage purposes.
  • Control algorithms supporting various applications and machines
    Sanken Electric inverters come with a rich array of control parameters and setting values as standard. They support various systems as standard.
  • Ease of use and security can be achieved through a communication function, a data lock function, and more.
    Our inverters feature a communication function (optional) that supports data busses, and strong security features, such as data lock and password functions.
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