A Review of Variable Frequency Drives

Variable frequency drives (VFD), which are also known as AC drives, frequency drives, inverters, speed drives, and micro-drives, are motor controllers capable of driving electric motors. The way this is accomplished is that the frequencies and voltages going to electric motors are varied.

Brief Introduction to Variable Frequency Drives

This type of adjustable speed drive is used primarily in electro-mechanical drive systems as a means of controlling torque but also AC motor speed by varying input voltage and frequency of the motor. There are several applications that use these drives to include smaller appliances to massive mine mill compressors.

Today, roughly 25% of electrical energy in the world is consumed by electric motors within various industrial applications. Using a variable frequency drive in centrifugal load service, motors save energy. Although these drives are extremely popular within North America, they hold a very small market in other parts of the world. The bottom line, installation of variable frequency drives could significantly improve energy efficiency.

Throughout the past four years, the cost and size of variable frequency drives has been dramatically reduced thanks to power electronics technology. In addition, overall performance has been improved upon through advances made in semiconductor switching devices, control and simulation techniques, control software and hardware, and different drive topologies.
For more detail visit here...

Contact Us:

Northern Industrial Supply Company Inc.
1730 McPherson Court, Unit #35
Pickering, Ontario
Canada, L1W 3E6
Email: niscopic@globalserve.com
Phone On: 905-831-8067

Benefits of Variable Frequency Drives

Also known as AC drives, variable frequency drives (VFD) are essentially controllers capable of driving electric motors, something accomplished by varying the voltage and frequency that goes into an electric motor.

AC Motor of Variable Frequency Drives

A variable frequency drive system uses an AC electric motor. Typically, this is a three-phase induction motor although a single-phase motor is also used on occasion. The benefit of a three-phase induction motor is that it works for most purposes and typically, it is the more cost-efficient solution. Keep in mind that when induction motors experience increased voltage stresses supplied by variable frequency drives, there has to be a design in place for definite-purpose inverter-fed duty.

Benefit of Energy Saving

A number of different load applications for a fixed speed motor supplied directly from AC line power save energy when operated with a variable frequency drive and at variable speeds.Original Source...

Contact Details:

1730 McPherson Court, Unit #35
Pickering,
Ontario, Canada
Zip Code: L1W 3E6
Phone No: 905-831-8067
Web: http://nisco.ca/
Email: niscopic@globalserve.com

Differences Between Axial and Centrifugal Fans

Although there are some similarities between centrifugal fans and axial fans, there are also distinct differences. Regardless, both types of fans are used for industrial applications.

Centrifugal Fans

Centrifugal fans, also referred to as blowers and squirrel cage fans because they resemble a hamster wheel, were invented in 1832 by Lt. Gen. Alexander Sablukov, a military engineer with the Empire Imperial Russian Army. This type of fan is capable of moving air, as well as other gasses. The speed of the airstream increases thanks to rotating impellers, which are a series of blades.

The various types include forward curved, backward inclined, radial, airfoil, radial tip, and inline. Two specific characteristics of the centrifugal fan are high pressure and low flow rate, with flow perpendicular to the blower axis. Fans designed with paddle impellers are ideal whenever debris passes through the system, thereby preventing clogs. For fans with blades that curve backward, the volume of air produced is less than with axial fans while the amount of pressure generated is more significant.

Original Source: http://nisco.ca/differences-between-axial-and-centrifugal-fans/

Contact Details:
1730 McPherson Court, Unit #35
Pickering, ON
L1W 3E6
Phone No: 905-831-8067
Web: http://nisco.ca/
Email: niscopic@globalserve.com

Centrifugal Fans – Basic Types and Associated Benefits

There are several different types of centrifugal fans, each with unique design characteristics, performance capabilities, and benefits. Often referred to as blowers, these industrial fans are used for high-pressure applications by a variety of industries, as well as air pollution systems.

These fans work by increasing the pressure of an incoming airstream by turning a series of blades (impeller) mounted on a circular hub. This accelerates the air as well as changes the direction of the air flowing outward, often by 90 degrees. In addition, these fans produce a steady airflow.

Basic Types of Centrifugal Fans

Below are the six most common types of centrifugal fans, each with a unique blade configuration.

• Forward Curved Fan – Also known as a squirrel cage fan due to the wheel type, this fan’s impeller is forward and somewhat small. In addition, the blades curve in the same direction as the rotation of the wheel. Because the impeller, shaft, housing, and bearings are delicately made, there are some limitations for sustainability when used for industrial applications. However, this fan is great for low-speed and low-pressure applications.

Original Source: http://nisco.ca/centrifugal-fans-basic-types-and-associated-benefits/

Contact Details:
1730 McPherson Court, Unit #35
Pickering, ON
L1W 3E6
Phone No: 905-831-8067
Web: http://nisco.ca/
Email: niscopic@globalserve.com

How to Improve Fan System Performance

Specific to air handling units, there are a number of ways to improve the performance of fan systems. In HVAC systems, fans use roughly 40% of all electricity. The problem is that even by following all of the proper procedures in selecting fans for HVAC use, low total efficiency persists. From 2005 to 2009, the Energy Concept in Sweden conducted performance measurements on 767 fans in HVAC systems. While a few of the fans had an efficiency between 50% and 60%, the majority reached only 33% for total efficiency.

For the most part, there is tremendous potential for improving on energy consumption of fan systems. Whether commercial, residential, or industrial fans in Canada, as much as 50% electricity could be saved with a more efficient design, as well as better strategies for control. Below are some examples of how the performance of fan systems can improve.

Variable Frequency Drive – A Variable Frequency Drive (VFD) is designed to adjust the speed of an electric motor based on load. Therefore, the motor speed is reduced and energy is saved. The exact efficiency of the VFD alone varies since the nominal output along with partial load cause the drive to lose between 2% and 5% of torque and speed. However, by implementing a Variable Frequency Drive in many applications, performance improves and energy consumption drops.

Original Source: http://nisco.ca/how-to-improve-fan-system-performance/

Contact Details:
1730 McPherson Court, Unit #35
Pickering, ON
L1W 3E6
Phone No: 905-831-8067
Web: http://nisco.ca/
Email: niscopic@globalserve.com