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Uninterruptible power supplies keep the lights on in the lab.

Plug in your lab equipment, turn it on, and never lose power. This exclusive MLO interview with Mike Stout, VP of Engineering at Falcon Electric provides valuable insight into how to keep the lab operating even with "dirty power," brown-outs, and power outages.


MLO: Can you tell us when you began to provide backup power to medical laboratories and why?

Stout: Falcon products have been sold to medical laboratories for more than 20 years. Some of our early customers were hospitals and clinical laboratories. The bulk of our medical-oriented sales were through OEM customers, such as Baxter Health Care, Beckman Coulter, and Wyeth, who bundled Falcon uninterruptible power supply (UPS) equipment with their own electronic medical products. With the advent of DNA sequencing, Falcon has also provided products to many research labs. In fact, Falcon UPS products were used to protect and back up the DNA sequencing equipment used for the Human Genome Project.

Further, we have supplied UPS units to the FBI Crime Lab and law enforcement agencies around the world. In addition, our voltage and frequency converters and UPS units are used by MIT Lincoln Labs, Sandia and Los Alamos National Labs, Lawrence Livermore National Lab, and CERN (the European organization for nuclear research). Our voltage and frequency converters are utilized when the project calls for the lab to deliver 230V/50Hz required for lab systems used overseas or when the instrument, designed to operate at 120V/60Hz, is being sent out of the United States and a converter is required.

The Falcon true double-conversion on-line UPS provides a high level of power protection against the widest range of power problems. The low-cost line-interactive, or "Smart UPS," primarily provides battery backup and has limited power-protection capabilities for suppressing high-voltage transients. In addition, voltage regulation can be poor. Basically, the utility power coming into these types of UPS units goes through some surge-protection circuitry and then out to the device. It is only when utility power is lost that a line-interactive's inverter turns on and switches in. Due to the low cost of the typical line-interactive UPS, the typical battery inverter output is a distorted sinewave having a high level of harmonic distortion.

By contrast, the output inverter in our double-conversion on-line UPS is operating continuously, both in AC utility and battery modes of operation. The Falcon UPS converts the incoming utility or generator power, filters it, and then rectifies it to DC. This removes all of the unwanted AC frequency and voltage problems, including generator frequency shift, voltage transients, voltage, and current harmonics. Once the UPS has converted the incoming AC to DC, it regulates the DC voltage and uses it to power our continuous duty insulated-gate bipolar transistor (IGBT) pulse width modulated (PWM) inverter.

This provides an output with superior voltage regulation (120Vac +/-2% domestic or 230Vac +/-2% European), even if the utility power supplied to the UPS drifts by +/-15%. As a result, any voltage sags and surges in the utility power are eliminated, along with most other power problems. Should the utility power be lost, the UPS will simply start to draw its power from the internal batteries without any switchover or transfer required.

The on-line UPS is like installing a "power firewall" between incoming power and sensitive laboratory equipment--essential for medical electronics, which often must be connected to outlets and circuits shared by heavy-duty equipment that can corrupt the quality of utility power. And, of course, medical gear is often most needed in times and places that utility-power quality suffers, is interrupted, or goes away for significant periods when the use of these instruments is paramount.

As the connected lab equipment is always receiving optimum power conditions and voltage, the equipment accuracy, performance, and reliability are assured, irrespective of the utility or lab outlet-power quality. Seamless backup-power capability is a secondary benefit. Additional battery banks may be added, providing up to several hours of backup.

MLO: Please describe your double-conversion on-line UPS units in more detail. How do they differ from standby power supply (SBS) units?

Stout: There are three basic UPS types, each offering more power protection than the preceding: Off-line (SBS), the lowest grade; line interactive (SBS), the middle grade; and on-line (UPS), the highest grade.

The off-line SBS offers bare-bones power protection for basic surge protection and battery backup. Through this type of SBS, equipment is connected directly to incoming utility power with the same voltage transient clamping devices used in a common surge-protected plug strip connected across the power line. When the incoming utility voltage falls below a predetermined level, the SBS turns on its internal DC-AC inverter circuitry, which is powered from an internal storage battery. The SBS then mechanically switches the connected equipment on to its DC-AC inverter output. The switch-over time is stated by most manufacturers as being less than 4 milliseconds, but typically can be as long as 25 milliseconds, depending on the amount of time it takes the SBS to detect the lost utility voltage.

The line-interactive SBS offers the same bare-bones surge protection and battery backup as the off-line, except it has the added feature of minimal voltage regulation, while the SBS is operating from the utility source. This SBS design came about due to the off-line SBS's inability to provide an acceptable output voltage to the connected equipment during brown-out conditions. A brown-out happens when the utility voltage remains excessively low for a sustained period. Under these conditions, the off-line SBS would go to battery operation; and, if the brown-out was sustained long enough, the SBS battery would become fully discharged, turn off the power to the connected lab equipment, and not be able to be turned back on until the utility voltage returned to normal. To prevent this from happening, a voltage-regulating transformer was added; hence, the term line-interactive was born. This feature really does help, as low-voltage utility conditions are common. The downside for this design is that most of the units available have to switch to battery momentarily when making transformer voltage adjustments, and the associated switch-over voltage transients may not be tolerated by many pieces of lab equipment, especially those that are microprocessor-based or have a connected computer system. The true advantage to the on-line UPS is its ability to provide an electrical firewall between the incoming utility power and sensitive laboratory equipment.

While the off-line and line-interactive designs leave the equipment connected directly to the utility power with minimal surge protection, the on-line UPS provides multiple electronic layers of insulation from power-quality problems. This is accomplished inside the UPS in several tiers of circuits. First, the incoming AC utility voltage is passed through a surge-protected rectifier stage where it is converted to a direct current and is heavily filtered by large capacitors. This tier removes line noise, high-voltage (Hz) transients, harmonic distortion, and all 50/60 Hertz (Hz) frequency-related problems. The capacitors also act as an energy storage reservoir giving the UPS the ability to "ride-through" momentary power interruptions. The battery is also connected to this tier and takes over as the energy source in the event of a utility loss. This makes the transition between utility and battery power seamless, without any interruption.

The filtered DC is sent into the next tier, a voltage-regulator stage. In the regulator stage, the DC voltage is tightly regulated and fed to a second set of storage capacitors. The regulator stage gives the UPS its ability to sustain a constant output even during sustained brown-out or low-line conditions. The additional stored energy in the second set of capacitors yields even more ride-through time without any battery drain. The regulated DC voltage is next fed to the inverter stage where a totally new 50/60 Hz, true AC sinewave output power is generated. This tier gives the UPS a new, clean output with superior voltage and frequency regulation, providing the ideal power source for laboratory equipment.

The on-line UPS can also provide other benefits like frequency conversion for operating equipment designed for a 60-Hz utility source on European 50-Hz utility power, or the reverse. The continuous duty inverter also allows for the connection of large extended battery packs that can provide up to several hours of backup time. In the case of a critical process like DNA sequencing in a crime lab where only one DNA sample may be available, this assures process completion in the event of long-term utility-power loss. Only the on-line UPS can provide the level of voltage regulation and power protection required by power-sensitive lab equipment.

MLO: Are the power quality and availability needs of medical laboratories in other countries greater than those in the United States, depending on where they are located?

Stout: Utility power in the United States and Europe is typically much better than the power quality in developing nations. Using this as a rule, however, is a poor measure of the power quality inside any specific lab located anywhere in the world--including the United States and Europe. One reason is localized power pollution often being created by other equipment operating on the same lab power circuits, which can happen anywhere. Large motors or other power-hungry devices in a lab can create voltage sags, surges, and even high-voltage transients that can disrupt the operation of sensitive lab equipment.

Also, many areas within the United States are subject to power utility problems--sags, rolling brown-outs, even power outages--due to seasonal conditions like a high rate of air-conditioning use during heat waves. During the rest of the year, power-line problems often are caused by snow and ice storms, hurricanes, tornadoes, and flooding. Other causes of power interruption include accidents due to construction, vehicles downing utility poles, or the ripple effect on the power grid from an event that may be a thousand miles away.

That being said, developing countries' power can present the harshest of power problems. Local power grids may be without power for several hours a day. This is often the case in locations like Iraq or Mexico City in the summer months. Voltage sags and surges may be excessive, even destructive, beyond the operational limits of most lab equipment. Differing countries have unique power problems.

To address these potential problems, Falcon's 230Vac European models are designed with the widest input voltage range, typically 170Vac to 275Vac, while providing a regulated user-settable 208Vac, 220Vac, 230Vac, or 240Vac output. We can also provide battery-backup options of up to several hours. In addition, we offer models with galvanic isolation (completely separating the input and output) for use in locations where grounding and common mode noise is a problem. In addition to our wide-input range European models supplied to developing-world customers, we also supply specialized rugged military systems in developing countries.

MLO: What about oversight in foreign labs regarding protecting refrigeration and other laboratory equipment?

Stout: Most medical labs throughout the world attempt to meet either U.S. or European standards. Of course, some laws change from country to country. In the case of vaccines, maintaining them in a proper refrigerated environment is critical to their viability and, as such, "universal" in nature.

Most UPS units are shipped with valve-regulated sealed lead-acid, or VRLA, batteries designed for a typical five-year life. The two factors that can drastically reduce the expected battery life are heat and allowing the batteries to become overly discharged. If the UPS is installed in an environment where the average temperature is 72[degrees], and the charge is maintained, it should last the five years. Should the same unit be installed in a 122[degrees] environment, the battery may only last about nine months. Should the UPS not be plugged in for a period of six to 12 months, the batteries may self-discharge down to the level where they cannot be recharged and must be replaced.

In our SSG Series laboratory and industrial grade on-line UPS, Falcon is the first to equip those with eight--to 10-year life batteries. Again, at 72[degrees], these will yield an eight-to 10-year life; at 122[degrees], these batteries may last only four years. Both are a vast improvement over the three- to five-year batteries. Allowing the batteries to become overly discharged, however, will result in the same battery damage. Our SSG Series UPS is UL Listed for operation in environments up to 55[degrees]C (131[degrees]F).

MLO: How can lab managers properly maintain their UPS units to make sure their equipment will operate in a disaster-recovery mode?

Stout: A UPS-testing plan is dependent on the level or critical nature of the connected lab equipment and associated process. In some cases, UPS testing may not be required. If the process is critical, we recommend the following plan. When the UPS is first received and connected to the lab equipment, allow the UPS to charge for 24 hours. Next, with the equipment operating normally, disconnect the utility power to the UPS, and use a stopwatch to record the amount of battery runtime until the low-battery alarm sounds. Immediately reconnect the utility power to the UPS. Record the amount of runtime in minutes and seconds on a label, along with the date, and attach the label to the top of the UPS. Every four months, conduct the 24-hour recharge and runtime test, and record the results on the label. When the battery runtime reaches 80% of the time recorded for the first (installed) runtime test, the batteries should be replaced. Our website has a UPS tutorial and other information for those who seek more in-depth details.

MLO: What are some common problems you see in clinical labs' UPS units?

Stout: First, improper selection of UPS type. Typically the lab purchases laboratory equipment based on its performance, with cost being secondary. They will, however, purchase a $120 UPS to protect a $50,000 piece of lab equipment with little research and without regard for the UPS performance. Second, they have no battery-testing plan or program. Third, improper installation of the UPS that does not allow for proper cooling. This shortens both the UPS life and battery life.

MLO: Did your company have backup systems in operation in New Orleans during Hurricane Katrina? If so, what was the outcome for labs with UPS units there?

Stout: Falcon, along with most other UPS companies, did have many UPS units operating in New Orleans during Hurricane Katrina. The big problem experienced by hospitals and labs occurred after the storm moved inland, and the city was flooded. Backup generators for the hospitals and large labs were located in lower levels of the buildings, below ground level. They were completely flooded and rendered unusable. This left the facilities with no long-term source of emergency power, since the UPS units installed were only intended to supply backup power for the limited amount of time during the emergency-generator startup. Therefore, the batteries were discharged during the first few minutes of the power outage.

This incident led many government agencies to issue new regulations specifying the installation of backup generators. These generators must now be installed on roof locations in hospitals, in addition to provisions implemented for mobile generator power connections outside the facility to allow a mobile generator to be driven or flown in as a third source of power to the hospital.

MLO: What challenges did/does Falcon Electric as an organization face in developing its global business?

Stout: The Internet is the vehicle that opens the world market up. In other words "the Internet is the great equalizer." Our website is not only our primary sales vehicle, it is also a power-information site: truly a toolbox that will solve many problems not addressed elsewhere.

Regarding logistics, our UPS units are small enough to be shipped all over the world and require minimal service that can be performed by the average lab technician. The only service required, aside from cleaning the unit to ensure airflow to internal components, is battery replacement. The simple instructions on this procedure are posted on our website. Should a unit need to be returned to the factory to repair damage from a power event, the batteries can be removed and the unit returned. Users remove the batteries to reduce the weight significantly, which saves on freight costs. In the case of our large-volume customers, we offer service classes to their technical staff and provide spare parts.

Reach Falcon Electric at, or call 800-842-6940 (toll-free in the United States), or 626-962-7770. Send comments to MLO Editor Carren Bersch at
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Title Annotation:DISASTER PREP; Falcon Electric Inc.; Mike Stout
Publication:Medical Laboratory Observer
Article Type:Interview
Date:Jan 1, 2010
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