Frequency Converters | Power Systems International

Carina House East, Sunrise Parkway,
Milton Keynes, MK14 6LS, United Kingdom

What is a static frequency converter?

Simply put, frequency converters are a power conversion device.

The frequency converter converts a basic fixed-frequency, fixed voltage sine-wave power (line power) to a variable-frequency, variable-voltage output used to control speed of induction motors. Available in many different types, frequency converters offer optimum method for matching pump and fan flow rates to system requirements. It converts standard plant power (220V or 380 V, 50 Hz) to adjustable voltage and frequency to power AC motor. The frequency applied to AC motor determines motor speed.The AC motors are usually same standard motors that can be connected across AC power line. By incorporating bypass starters, operation can be maintained even if inverter should fail.

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Our range of Static Frequency Converters...

Why use a frequency converter?

The following describes speed reduction and corresponding energy savings. In addition to energy savings, impeller, bearing and seal life is greatly improved.

For example, in aquatic applications the primary function of a frequency converter is to provide energy savings. By controlling the speed of a pump rather than controlling flow through use of throttling valves, energy savings can be substantial.

By way of example, a speed reduction of 20% can yield energy savings of 50%.

Frequency converters also offer an additional benefit

increased bearing and pump seal life. By maintaining only pressure needed in pump to satisfy system requirements, the pump is not subjected to any higher pressures than necessary. Therefore, the components last longer.

Additional benefits of Frequency Converters

In addition to energy savings and better process control, frequency converters can provide other benefits:

  • A frequency converter may be used for control of process temperature, pressure or flow without use of a separate controller. Suitable sensors and electronics are used to interface driven equipment with frequency converter.
  • Maintenance costs can be lowered, since lower operating speeds result in longer life for bearings and motors.
  • Eliminating throttling valves and dampers also does away with maintaining these devices and all associated controls.

The same benefits – but to a lesser extent – also apply to fans operated by frequency converters.

To obtain optimum efficiencies and reliability, many specifiers obtain detailed information from manufacturers.

This may include frequency converter efficiency, required maintenance, diagnostic capabilities within frequency converter, and general operational features.

Then, they make detailed analysis to determine which system will give the best return on investment.

Additional benefits of Frequency Converters
  • A soft starter for motor is no longer required.
  • Controlled ramp-up speed in a liquid system can eliminate water hammer problems.
  • Ability of a frequency converter to limit torque to a user-selected level can protect driven equipment that cannot tolerate excessive torque.

Useful information

Analyse System as a Whole

Since the process of converting incoming power from one frequency to another will result in some losses, energy savings must always come from optimizing the performance of the complete system.

First step in determining energy savings potential of a system is to thoroughly analyze the operation of entire system. Detailed knowledge of equipment operation and process requirements are required in order to ensure energy savings. In addition, type of frequency converter, features offered, and overall suitability for application should be considered.

Frequency Converters Internal Configuration

Frequency converters contain three primary sections:

Rectifier Circuit – consists of diodes, SCRs, or insulated gate bipolar transistors. These devices convert AC line power to direct current.

DC Bus – consists of capacitors that filter and store the DC charge.

Inverter – consists of high-voltage, high-power transistors that convert DC power to a variable-frequency, variable-voltage AC output delivered to load.

Frequency converters also contain a powerful microprocessor which controls inverter circuit to produce an almost pure variable-frequency sinusoidal voltage delivered to load. The microprocessor also controls input / output configurations, frequency converter settings, fault conditions and communication protocols.

What sectors can benefit from Static Frequency Converters?

Our client’s are generally internationally recognised companies, often leaders in their fields. Whilst most of our clients are UK based, we have a wide range from Japan, though the Middle east and over the the USA. Our focus is on providing the right solution for our client’s, where they are based is less of a concern for us.

Downloads & Resources

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Heavy Duty Frequency Converters

Filetype : pdf
Filesize : 425 KB
Uploaded : 19/08/2022
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Shore Power Frequency Converters

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Filesize : 296 KB
Uploaded : 27/07/2022
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