True “On-Line” Technology for Maximum Power Protection:
Many UPS designs use the commercial power as the primary source and conditioned inverter
power only when power fails. These designs are referred to as “standby”, “line interactive”, “single
conversion”, “forward transfer”, and “off-line” UPS and do not provide adequate protection for your
critical load. Consequently, with these UPS topologies, the load is connected directly to the
contaminated commercial AC power and is constantly bombarded by power aberrations coming
down the line. Some manufacturers falsely promote these designs as On-Line UPS. Consumers
must not confuse “off-line” or “single conversion” UPS designs with a true “On-line” double
conversion UPS technology.
True On-Line, double conversion UPS systems isolate and protect the critical load from the
contaminated commercial AC power. The load receives a continuous flow of clean, isolated and
regulated AC from the on-line inverter. The double conversion process converts the contaminated
commercial AC power into a regulated and filtered direct current (DC). The on-line inverter
reconstructs the DC into a new, clean, and regulated AC power source. The critical load is
supplied only from the pure inverter AC output. There is no better protection for your critical load.
The LTI ProUPS Series is a True “On-line” design providing continuous, isolated and conditioned
AC power. The benefits are numerous including reduced operating costs, extended hardware life,
and total power protection.
Input Power Factor Correction:
Input power factor correction (PFC) is a considerable money saving feature. Most UPS
manufacturers only offer PFC as an expensive and complex add-on filter. LTI provides as standard
on all UPS models a cost effective, highly efficient, and reliable PFC circuit. Our unique power
factor correction circuit has only three bi-directional active devices that switch at the zero crossing
of the input sine wave. This unique PFC circuit configuration keeps the component count down
and efficiency up. Power companies charge higher rates to consumers based on their power
factor. Most equipment, including other brands of UPS, have typical input power factors of 0.8 or
less resulting in higher monthly operating costs.
Input Total Harmonic Distortion (THD) Less Than 4%:
Low input total harmonic distortion is an important feature especially in 20KVA and larger UPS.
The input THD represents the amount of distortion that the UPS reflects back into the power
source. If a UPS has a high input THD, the distortion can affect the entire building's AC power
grid. This could create power problems for other equipment connected to the same input feeder
as the UPS. All LTI ProUPS have an excellent input THD which is typically less than 6% at no load
and less than 4% at full rated load.
True Double Conversion Design:
There is no better power protection than a true double conversion UPS design. In a double
conversion design, the incoming AC power is rectified into a regulated direct current (DC) source.
The DC is then used to charge the battery and supply input power to the inverter section of the
UPS. The inverter reconstructs the DC into new and pure AC power. This new isolated AC source
is then fed through the static switch to the critical load. The double conversion process from AC to
DC and DC back to AC isolates the critical load from power problems. Fluctuations in the
commercial AC power or even total loss of input AC will not affect the power to the critical load.
Low DC Bus Voltage:
The DC Bus voltage is critical to the reliability and long term costs associated with any UPS. The
reason for this is simple. Due to the corrosive properties, temperature changes, number of
connection points, etc. the battery plant can easily be considered the weakest link in any UPS
system. They require the most maintenance, and are usually the first components in a UPS
system to need attention. If the amount of batteries in a system can be minimized, you can greatly
cut down on the overall costs associated with maintaining and replacing them further down the
road. When compared to most other UPS, LTI systems are designed with the lowest possible DC
link voltages -- most commonly 120VDC.
No Break Fail Safe Static Bypass Switch:
The purpose of a static switch is to transfer the load between the inverter AC source and the
backup commercial AC source. To prevent any loss or degradation in the output power this must
be done as quickly and smoothly as possible. To cut costs, many manufacturers use undersized
SCRs as the switching device and then parallel a contactor to carry the load current before the
small SCRs overheat and fail. All LTI static switches use fully rated inverse-paralleled SCR’s
sized to carry not only the full load continuously, but also up to a 2,000% sub cycle overload. Our
method results in an instantaneous transfer (0 ms) without any contactors or other noise-
generating mechanical devices. Unlike other static switches, LTI's design is fail-safe to provide
the best redundancy possible.
Reliable and Robust Design:
The very nature of a UPS installation requires operation 24 hours a day, 365 days a year without
loss of output power. It is imperative for reliable operation to have a UPS system that is built
robust to meet these demanding conditions. Our UPS have redundancy designed into each unit to
eliminate single point failures. Heat will cause premature failure in any electronic component. LTI
has taken special steps to monitor the internal temperature of critical components and provide
additional cooling. In addition to this, all LTI UPS systems contain fully rated components, where
the competition often uses undersized components to save money. All of this results in cooler
operation, less stress on each device, and a longer performance life.
Highest Quality Components Including Copper Wound Transformers:
All components used in LTI UPS are selected for high quality and reliability. We strive for the
highest mean time between failure (MTBF) figures in the industry. Our excellent performance is a
direct result of using only high quality parts, such as: Sealed ball bearing type fans, De-rated
power devices, Class H type full isolation copper wound transformers, heavy gauge powder
coated steel cabinets and hardware, 100% tested components and a minimum 24 hour system
burn-in.
Quality EMI/RFI Filtering:
LTI UPS have high frequency pi filters installed on all input and output AC terminal blocks of the
UPS. These filters prevent high frequency noise from affecting sensitive equipment connected to
or located adjacent to the UPS. As a result, LTI UPS can be located right next to critical load
devices such as radio and TV transmitters, medical equipment, monitors, and other highly
sensitive apparatus.
RJ45 Network Communications Kit:
LTI UPS can be connected and monitored through an ethernet network by plugging into the RJ45
connector and using the included software. The Modbus capable interface software can be used
to monitor the UPS status and conditions remotely, as well as send shutdown messages via SMS
and SNMP to safely shut down servers and workstations before it's too late.
Data Logging:
The LTI UPS internal event logger will store the last three thousand events in internal memory. For
cradle-to-grave data logging, the UPS can be connected to a network computer for even more
event file storage.
Form “C” Interface Contacts:
Both normally open and normally closed dry contacts allow for flexible interfacing with most alarm
and monitoring systems. Additional custom alarm sensing and monitoring options can also be
added.
Built to Stringent UL/CUL 1778, UL 1080S, NEMA, NEC, ANSI, and FCC Requirements:
LTI UPS are designed to meet the requirements of many industry and application standards
around the world.
Custom Configurations Available:
Each UPS system is configured, tested, and shipped for a specific input and output voltage but
each can be reconfigured to operate on custom voltages or frequencies. This is particularly
advantageous if the UPS needs to be moved to another location in the future.
