IRWINDALE, Calif., 8 May 2011. Precision timing systems designers at Symmetricom Inc. in San Jose Calif., needed rackmount on-line uninterruptible power supplies (UPSs) to ensure the flow of reliable power to the Symmetricom Time-Scale systems the company provides systems integrators with time-sensitive needs. They found their solution from Falcon Electric Inc. in Irwindale, Calif.
Symmetricom designs precision-timing devices like atomic clocks, which provide the correct time. Some of Symmetricom's customers spend more than a half million dollars on equipment that provides this information, and a mundane problem like a power interruption simply cannot be allowed to interfere, explains Ron Seredian, vice president of marketing at Falcon Electric.
Symmetricom chose Falcon Electric's SG Series 2 kilovolt ampere rackmount UPS (Model SG2KRM-2TU), a 2U (3.5 inch high) on-line UPS, and the associated rackmount slides to put them into two racks, plus Falcon's SNMP network cards. "The SNMP card provides UPS status information," says Tim Erickson system integration manager at Symmetricom.
"We also bought the extended battery bank modules. We were looking to provide six hours' worth of backup, so we configured with four battery backup extension modules," Erickson says. "Falcon's UPSs do exactly what we need and they're easy to use," explains Erickson. "We hook them up, set them and forget them. And Falcon's customer service was great; the response time and delivery was exactly what they said they'd do."
Applications that require precision-timing devices such as those Symmetricom provides include military range finding, signals intelligence (SIGINT), Global Positioning System (GPS)-based satellite navigation, electronic test and measurement, unified handoff of cellular calls, timely receipt of data packets, management of the electric power grid, and the ability to protect against cyber threats.
Symmetricom products are deployed in more than 90 countries, including in wireline and wireless networks, instrumentation, testing applications, and network time management, Seredian says. One product used by organizations to establish a local source of traceable time is Symmetricom's Time-Scale System, an integrated timing system incorporating several different high-performance atomic clocks.
Even the most reliable power sources can have problems. Storms, floods, ice, earthquakes, accidents, or equipment failures can cause power to go down. Without proper precautions, power problems can disrupt current processing, mangle stored data, force system shutdown to prevent over-heating, shorten hardware lifetime, and even destroy components, Seredian says.
UPS devices from Falcon Electric shield electronic equipment from power problems, including providing back-up power from its battery to supplement under-voltage from the utility or act as an alternate power supply during outages, whether due to utility loss or some other power problem, Seredian explains.
When protecting critical systems, such as precise time systems from Symmetricom, Falcon Electric provides double-conversion, on-line UPS devices to protect not only against blackouts, but also more frequent and subtle, yet damaging power disturbances.
The double-conversion on-line UPS is designed with a continuous-duty inverter circuit. The inverter produces new sinewave output power while operating from the incoming utility source, or when not available, from its internal or external battery sources, Seredian says. The incoming alternating current (AC) utility or generator power is rectified to an unregulated direct current (DC) and filtered. The batteries are also connected at this point.
The unregulated DC from the utility or the DC from the batteries is fed to a regulating boost chopper or DC-DC converter circuit. This provides regulated power at a suitable voltage to the input of the DC-AC inverter circuit. The DC-AC inverter circuit then regenerates clean tightly regulated, true sinewave AC power.
"We have a power holdover requirement for the Time-Scale System," Erickson explains. "We need to provide uninterrupted back-up power for a certain length of time, typically hours."
Until recently, most of Symmetricom's products that required back-up power needed direct current (DC) power, which a battery could supply, yet "the power input to the Time-Scale System is AC-only," Erickson points out; there's no DC input. One option, he explains, was to get an inverter, which would convert the DC power from the back-up battery to AC. But this would require Symmetricom to buy or build, and integrate, the associated circuitry to perform the transfer between utility power and the inverter, including determining when to transfer between modes.
Instead, to ensure the Time-Scale System could weather hours-long power outages or brown-outs, Symmetricom looked for UPS systems that could perform these tasks, along with incorporating other power protection including guarding against surges and spikes. Symmetricom wanted a high-quality, dependable UPS in a rackmount form factor, so customers could install it in the same racks used for the Time-Scale System.