November 2014 Electro Static Technology

AEGIS® Rings Make Sense forThe Environment and Your Bottom Line

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VFDs Deliver Energy Savings, butAEGIS® Rings Make These Savings Sustainable

With the growing emphasis on “green” buildings and processes and the quest for LEED certification, more and more building designers, specifying engineers, and process engineers are turning to variable frequency drives (also known as VFDs or inverters). One of the most promising energy savings technologies today, VFDs can be used to control the speed of a motor, thereby reducing the energy required to run it by 30% or more. Consequently, they are being used more and more in building and processing systems including HVAC compressors, air handlers and fans, evaporators, condensers, circulating water pumps, processing and transfer pumps, and materials handling and distribution systems.

But VFDs are not without their drawbacks. They induce harmful voltages on the shafts of the motors they control — voltages that can discharge through bearings, destroying them and severely diminishing the reliability of entire systems. And, the cost of repairing or replacing damaged bearings can wipe out any cost savings generated by a VFD.

To make HVAC systems sustainable as well as energy-efficient, proven long-term bearing protection is required.

Proven in over a half million installations worldwide, AEGIS® Shaft Grounding Rings are the most reliable and cost-effective method available today for protecting motors from electrical bearing damage. Unlike discrete-point brushes, AEGIS® Rings are designed with continuous circumferential rows of conductive microfibers that encircle the motor shaft to maintain a low-impedance path from shaft to motor frame. Because the microfibers ride on the shaft with barely any friction, they do not require frequent replacement, unlike conventional grounding brushes. Also unlike conventional brushes, they remain effective in the presence of moderate amounts of dirt, grease, and other contaminants.

Thankfully, architects and engineers are becoming better informed about the trade-offs from using VFDs and the need for long-term bearing protection. It’s no wonder AEGIS® Shaft Grounding Rings have become the most specified solution to the growing problem of electrical bearing damage.

In their quest for energy efficiency, architects and consulting-specifying engineers are turning to variable frequency drives (VFDs) to reduce the power consumption of motors. But VFDs can induce harmful voltages on the shafts of the motors they control - voltages that can destroy bearings, shorten motor life, and leave critical building systems inoperable.

Typical of unprotected motors, the waveform above shows shaft voltage building up (to as much as 70 volts or more, peak-to-peak) until it overcomes the dielectric properties of the bearing grease and discharges destructively through the bearing.

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To download a new white paper on how to specify AEGIS® Bearing Protection rings, click here.

For a sample of actual AEGIS® specifications in various construction specs, see our Construction Projects Brochure.

Or for a case study for contractors on the costs of failing to provide shaft grounding, click here.

In motors with AEGIS® Bearing Protection Rings, harmful shaft voltage is safely and continuously channeled to ground, preventing bearing damage and extending motor life.

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AEGIS® Rings Deliver Dramatic ROIs

Installing AEGIS® Rings not only makes sense from the standpoint of process reliability and prevention of downtime, it makes great sense financially even if you consider only the costs of replacing damaged motors.

Consider the following facts:

• Typically motor bearings are designed for L10 life of 40,000 - 60,000 hours (depending on type of bearing and the conditions under which the motor/systems operate). Assuming 24-hour per day operation, this L10 life equates to 4.6 - 6.8 years of operation.

• Electrical discharges produced by variable frequency drives (VFDs) can decrease life by 50-70%. As a result, a motor that should last 4.6 - 6.8 years will, when controlled by a VFD, typically last only 1.4 - 3.4 years!

For this analysis, we have ignored the installation cost of the original motors. We have, however, assumed a very modest labor cost of $100 for the installation of each replacement motor.

Return on Investment: Installing AEGIS® Ring on 10 HP VFD-Driven Motor

Motor Life Shortest Longest

Cost of Ownership WITHOUT AEGIS® Bearing Protection

Cost of new motor WITHOUT AEGIS® protection $1000 $1000

L10 motor bearing life (running 24/7) hours/years 40,000 / 4.6 60,000 / 6.8

% of L10 bearing life WITHOUT AEGIS® protection 30% 50%

Average motor life WITHOUT AEGIS® protection hours/years 12,000 / 1.4 30,000 / 3.4

Motor replacements required to achieve the L10 life 3 1

Cost of replacement motors (motor cost plus installation) $3300 $1100

Total cost of new motor + replacement motors to reach L10 life $4300 $2100

Annual Cost of Ownership (excluding downtime costs) $935 $309

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P r o t e c t i n g V F D - D r i v e n M o t o r s I n :

Distribution Centers

E l e c t r o S t a t i c T e c h n o l o g y | 1 - 8 6 6 - 7 3 8 - 1 8 5 7 | w w w . e s t - a e g i s . c o m

Faster Deliveries With Greater Energy EfficiencyIn their efforts to minimize inventory and maximize ROI, many companies have adopted just-in-time stocking practices. The warehouses and distribution centers that serve these companies have had to become fast and flexible. The use of VFDs on materials handling and delivery systems not only saves energy, but by precisely controlling motor speeds, it ensures smooth conveyor operation and improves the materials handling process.

The Promise of VFDsVFDs reduce energy consumption by allowing motors to run less than full speed. When used to control conveyor, brake, and HVAC motors, they can yield energy savings of 30% or more by running motors at reduced speeds to compensate for changes in load.

The Need for Shaft Grounding on VFD-Driven MotorsBut, VFDs can damage the motors they control. They induce currents on motor shafts that discharge through the bearings, causing pitting, fluting, and catastrophic motor failure. Without bearing protection, any savings from the use of VFDs can be quickly wiped out by the cost of replacing motors and by system downtime. To make conveyor systems sustainable as well as energy efficient, a reliable method of bearing protection is required.

Proven, Long-Term Bearing ProtectionBy diverting bearing currents safely to ground, AEGIS™ SGR Shaft Grounding Rings ensure the reliable, long-term operation of VFD-driven motor systems, locking in energy savings and making these systems truly sustainable and truly green!

Applications:

Belt or steel hinged conveyors

Incline or decline conveyors

Line shaft conveyors

Belt over roller conveyors

Powered roller conveyors

Live roller conveyors

Brake motors

HVAC systems and air handling units

Refrigeration systems, condensers, and pumps

Ventilation fans

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Presenting AEGIS® at ELECTRIC POWER CHINA

Adam Willwerth, Sales & Marketing Manager for AEGIS®, recently delivered a presentation on AEGIS® Shaft Grounding Rings at ELECTRIC POWER CHINA. The 2014 International Exhibition on Electric Power Automation Equipment and Technology was held on October 22-24 at the China International Exhibition Center in Beijing. More than 26,000 visitors from over 40 countries visited the exhibits and attended conferences and presentations on topics such as Smart Grid technology, power automation, green power generation, and power transmission and distribution.

Mr. Willwerth’s presentation “Bearing Protection and Shaft Grounding Best Practices for Power Generation and Large Motors” was very well-attended and was followed by a lively Q&A session.

Traffic in the exhibit hall was brisk. So brisk, in fact, that more than 80% of this year’s show exhibitors plan on participating in next year’s ELECTRIC POWER CHINA Exhibition and Conference, which will be held in Shanghai in October 2015.

Adam Willwerth, AEGIS® Sales and Marketing Manager, explaining the need for shaft grounding of VFD-driven motors and the unique advantages of AEGIS® Bearing Protection Rings at ELECTRICPOWER CHINA 2014. Adam’s presentation was enthusiastically received and followed by a lively question and answer session.

Electro Static Technology31 Winterbrook RoadMechanic Falls, ME 04256

www.est-aegis.comToll-Free: 1-866-738-1857

TEL: (207) 998-5140FAX: (207) 998-5143

Return on Investment: Installing AEGIS® Ring on 10 HP VFD-Driven Motor

Motor Life Shortest Longest

Cost of Ownership WITH AEGIS® Bearing Protection

Cost of new motor WITH AEGIS® installed $1150 $1150

L10 motor bearing life WITH AEGIS® installed hours/years 40,000 / 4.6 60,000 / 6.8

% of L10 bearing life WITH AEGIS® protection 100% 100%

Motor replacements required to achieve the L10 life 0 0

Cost of replacement motors (motor cost plus installation) $0 $0

Total cost of new motor + replacement motors to reach L10 life $1150 $1150

Annual Cost of Ownership WITH AEGIS® Bearing Protection $250 $169

Annual Cost Savings WITH AEGIS® Bearing Protection $685 $140

% Annual Cost Savings 73% 45%

ROI from Using AEGIS® Bearing Protection 457% 93%