Page 105 - E24 Electrical Notebook

Eaton Uninterruptible Power Supplies (UPS) - 101

Solutions for Nine Power Problems For small office / home office (SOHO) applications, Eaton offers low-cost
solutions such as the Eaton 3S and Eaton Ellipse ECO UPS for the
Eaton UPSs address all of the nine common power protection problems protection of general desktop systems. For safeguarding mission-critical
described below. They are designed to meet the power protection, systems like network servers and power-hungry blade servers, Eaton’s
distribution and management needs of offices, computer networks, data offering includes line-interactive and online UPSs such as the Eaton 5PX,
centres as well as in the telecommunications, healthcare and industrial 9130, EX, 9PX, 9155, 9355, 9395, 93PM, 93E and BladeUPS.
markets.

Power problem Definition* Cause* Solution

Power failure A total loss of utility power Can be caused by a number of events: Single-phase Series 3 UPS Passive standby topology (offline)
lightning strikes, downed power lines, Single-phase Series 5 UPS
grid over-demands, accidents and natural Single and three-phase Series 9 UPS AC to DC DC to AC
disasters. Rectifier Inverter

Triggered by the startup of large loads, Battery
utility switching, utility equipment failure,
Power sag Short-term low voltage lightning, and power service being Line-interactive topology
insufficient to meet demand. In addition
Power surge Short-term high voltage to causing equipment crashes, power Buck Boost
(spike) above 110 per cent of sags can also damage hardware.
nominal AC to DC DC to AC
Can be caused by a lightning strike and Rectifier Inverter
can send line voltages to levels in excess Battery
of 6,000 volts. A spike almost always
results in data loss or hardware damage.

Undervoltage Reduced line voltage for Can be caused by an intentional utility
(brownout) periods ranging from a few voltage reduction to conserve power
minutes to a few days during peak demand periods or other
heavy loads that exceed supply capacity.

Double conversion topology (online)

Overvoltage Increased line voltage for Triggered by a rapid reduction in power Internal Static Bypass
periods ranging from a few loads, heavy equipment being turned
Electrical minutes to a few days off, or by utility switching. Can result in AC to DC DC to AC
line noise damage to hardware. Rectifier Inverter
High frequency waveform Battery
Frequency caused by EMI interference Can be caused by either RFI or EMI
variation interference generated by transmitters,
welding devices, SCR driven printers, Normal operation
Switching lightning, etc. Battery power
transient
A change in frequency Resulting from generator or small
stability co-generation sites being loaded and
unloaded. Frequency variation can cause
Instantaneous under- erratic operation, data loss, system
voltage (notch) crashes and equipment damage.

Normal duration is shorter than a spike
and generally falls in the range of
nanoseconds.

Harmonic Distortion of the normal Switch mode power supplies, variable
distortion line waveform, generally speed motors and drives, copiers and
transmitted by nonlinear loads fax machines are examples of non-linear
loads. Can cause communication errors,
overheating and hardware damage.

*Reference IEEE E-050R & old FIPS

Eaton Electric Ltd Eaton Sales Support
221 Dover Road Tel : 01753 608 750
Slough Fax : 01753 608 995
Berkshire
SL1 4RF Email: UKITSales@Eaton.com