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Along with a good power conditioning
strategy it’s also important to purchase good power
equipment. Here are some criteria and factors to consider
when purchasing power equipment. by Soutiman Das Gupta
A good power conditioning strategy
is a critical subset of Business Continuity Management
(BCM) and allows companies to maximize business uptime
for critical applications. While a UPS allows uninterrupted
power, power conditioning addresses a wider scope.
"A power conditioning
solution takes into account the business network blueprint,
from the grid (incoming) power stage to the load (equipment
requirement) stage. The solution should ideally be planned
at the blueprint stage and implemented, with the rest
of the cable, wiring and equipment installation to allow
correct measurement at every phase," advises Shrikant
Bapat, Country Champion-Uptime Solutions, Emerson Network
Power (India).
And to ensure that
your power conditioning solution will not let you down,
it’s very essential to make the right purchases of equipment.
Many organizations are unable to understand the need
for a network uptime solution and hesitate from making
this investment, though it may be just one percent of
their IT budget. "To them our advice is that to
be truly, globally, competitive, it is critical to accurately
assess the cost of downtime to your business and put
this in a ROI perspective," says Bapat.
Factors to consider
Here are some factors
to consider while determining a power conditioning solution.
There must be:
- An alternate source of power
(backup power).
- UPSs that adhere to the
specifications of the power equipment. It should have
a bypass line connection, and include a surge diverter
and a powerline filter.
- An Isolation transformer
at the input of the UPSs.
- Earthing and bonding.
- Alternate distribution.
- Static switches.
- A SCVS - Servo Controlled
Voltage Stabilizer
- Site and load study.
- A log book for battery monitoring
and maintenance.
Criteria for selection
of equipment
Manoj John, Industry
Manager, Industrial Technologies Practice, Frost &
Sullivan (India) suggests a number of criteria for selection
of power conditioning equipment.
Match capacity
with load requirements: The Watts ratings on hardware
do not always accurately represent the amount of power
it consumes. One should either measure the actual power
drawn by the equipment or select a UPS with a VA rating
that significantly exceeds the rating shown on the equipment.
Consider hardware
and software features: For example, if the UPS is supporting
a group of servers, you should use communication software
which has the ability to close applications running
on each server and ensure its safe shutdown.
Understand topologies:
There are three types of UPS topologies- online, offline
and line interactive (See story, ‘Powering up your business’).
Each provides different types of advantages and disadvantages.
Decide on the topology apt for your enterprise.
Vendor warranty
and onsite service options: Explore all the possible
warranty alternatives with the vendor to choose the
one most convenient.
Compare specifications:
The specifications are:
- The more maximum output
load in the current capacity (expressed in amps and
time duration), the better.
- The more transient voltage
surge suppression capability (expressed in joules),
the better.
- The faster output response
time the better.
- The faster battery recharge
time the better.
- More the number of AC outlets/sockets
the better.
Battery life: Information
about the specified battery life, recommended environmental
conditions, and whether user-replaceable is important.
Warning systems
and checks: Check for alarms or LEDs that indicate mains
failure, output overloads, whether the inverter is running
on UPS battery, and whether the battery charge is low.
Value offerings
with high cost: If you buy a more expensive unit, get
the one with software that automatically saves data,
closes applications, and turns off the computer equipment
in advance, before the UPS standby power goes out, following
the mains failure.
Compare warranties
and insurance guarantees: This is among the top reasons
for customers not reaching target ROIs on IT equipment
purchases. The gray market today is flourishing and
tie-ups with PC manufacturers and assemblers are rampant.
The only surety of quality equipment and post-sales
service is warranties and insurance guarantees.
Additional features:
There are UPSs in the market with modem surge protection,
Electromagnetic Interference (EMI) and Radio Frequency
Interference (RFI) noise filters. Consider them if these
specifications and protections are of major concern
for your sensitive hardware.
Soutiman Das Gupta
can be reached at soutimand@networkmagazineindia.com
- 1. Use fuses and circuit breakers liberally.
This protects the equipment, users, facilitates
troubleshooting, and minimizes potentially dangerous
situations.
- 2. Power is like putting food into your body.
Clean up power to reduce problems.
- 3. Follow good grounding practices.
- 4. For control systems, use a surge suppressor,
isolation transformer, and UPS. Your control
system will have fewer glitches.
- 5. Any cables that go outside should have
lightning protection.
- 6. The more accurate the signal you are trying
to measure, the more you need to do to clean
your power.
- 7. Motors and drives are the worst at generating
noise. Preferably use EMI filters or at least
reactors to minimize the noise.
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Different earthing systems need to be understood
before primary surge protection is implemented.
The most common earthing systems are shown:
- TN-S - A separate neutral and ground conductor
are used. The ground conductor can be the metallic
sheath of the power cable or a separate conductor.
All exposed parts of the installation are connected
to ground
- TT - One point of the source of energy is
grounded and the exposed-conductive parts are
connected to independent grounded electrodes.
- TN-C - Neutral and Ground conductors combine
in a single conductor throughout the system.
All exposed conductive parts are connected to
it.
- IT - A system that has no direct connection
between live parts and ground. All exposed conductive
parts of the installation are connected to independent
grounding electrodes.
- TN-C-S - Neutral and ground combine in a
single conductor.
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A common mistake made when buying a UPS is looking
at its ‘VA number’ (Volt-Amps) and confusing
this power measurement with ‘Watts’.
Watts equals Volts multiplied by Amps. So if your
server or switch needs 1000 W, a UPS with 1000
VA may not be sufficient.
An electrical device is never 100 percent efficient
in the way it handles power. This inefficiency
is rated in a little number called ‘power
factor’. It’s found somewhere in the
fine print of UPS documentation.
The power factor usually ranges between 0 and
1. It’s multiplied with the VA number to
get the real number of watts that should be the
output of the UPS.
So if the power factor of a 1000 VA UPS is 0.7,
then your UPS actually can handle a load of 700
watts. Consequently, your 1000 W server may also
not need 1000 W due to its power factor rating.
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Table with information
about different vendors’ offerings
| Company
|
Model
No. |
Used
in |
Specifications
|
Features
|
Contact
|
|
Invensys |
Powerware
9315
|
Data
Centers, Telecom switches and equipment |
40–400
kVA |
-
Transiet response: Less than 5%
- Power
factor: 0.95
- Dual
feed inputs
- SNMP
capability
- Power
monitoring and management software compatible
- Automatic
step-by-step shutdown of critical hardware
- Remote
notification over pager, e-mail, and telephone
- Intelligent
input filter
- Advanced
Battery Management
|
Invensys
Energy Systems Ltd.
4, Community Center,
Panchsheel Park,
New Delhi – 110017
Tel. 011-6499414-8
Fax. 011-6499419
E-mail: invensys@vsnl.net
www.invensys.energy.com |
| Powerware
9340 |
Data
Centers, Server Farms, Broadcasting services |
80-140
kVA |
-
Output: 380-415 V (selectable)
- Backup
Time: 5-45 minutes (extendable upto several hours)
- Overload
capability (inverter): 110% for 10 min, 125% for
1 minute, 150% for 10 sec
- Power
factor: 0.7-0.9
- Automatic
step-by-step shutdown of critical hardware
- Advanced
Battery Management
|
| Powerware
9305 |
Server
farmsIndustrial automation |
7.5
– 60 kVA |
-
Output: 220-480 V (selectable)
- Backup
time: 7-18 min
- Overload
capacity (inverter): 101-110% for 10 min, 111-125
for 1 min, 126-150 for 30 sec
- Power
Factor: 0.96
- Advanced
Battery Management
|
|
APC |
Symmetra |
Data
centers, Server farms |
Scalable
to 16 kVA |
-
Output: 220-2406000 VA
- Backup
at full load : 5.2 minutes (11200 W)
- Backup
at half load 17.1 minutes (5600 W)
- Built-in
automatic bypass
- Hot
Swap Batteries
- Power
expansion capability
- Battery
recharge time: 3 hours
- Built-in
Web/SNMP management
|
APC,
IndiaBuilding No 6,
1st Avenue, Indiranagar,
Adyar Chennai,
Tamil Nadu 600 020
India
Tel. 044-24450900/0556
E-mail: isbinfo@apcc.com
www.apcc.com |
| Silicon
|
Data
centers, server farms, communication equipment |
Scalable
to 150 kVA |
-
Input frequency: 50/60 Hz
- Built-in
Web/SNMP management
- 200%
overload capability
- Built-in
static bypass switch
- Uses
external battery system
|
|
Emerson
Network Power |
Liebert
3 phase UPSsSeries 600 – 60 HzNpower – 60 HzSeries
300 - 60 Hz |
Facility-wide
networks, medical equipment, industrial processes,
server rooms |
65
– 1000 kVsA |
-
Critical bus MTBF in excess of one million hours,
based on actual field experience with more than
1300 systems
- ASICs
(Application-Specific Integrated Circuits) and
IGBTs (Insulated Gate Bipolar Technology) enhance
system reliability
- Units
are compact and quiet
- Full-featured
monitoring and alarm systems are displayed in
easy-to-read text and graphics on a large LCD
monitor
- High
energy efficiency design saves money on operating
costs
|
Emerson
Network Power
(India) Pvt. Ltd.
Plot No. C-20, Road No. 19
Wagle Industrial Estate
Thane (W),
Maharashtra,
India
Tel. 022-2580 7108/2388
Fax. 022-2582 8358,2580 0829
E-mail: suhas.joshi@emersonnetwork.co.in
www.emersonelectric-ap.com/india/corp/
|
| Transfer
SwitchLiebert Smart Switch - 60Hz |
Facility-wide
networks, medical equipment, industrial processes,
server rooms |
Upto
400/230 (3 phases) |
-
Fast switching between two AC power sources
- Manual
and automatic transfer capability
- Selectable
preferred input source
- Integral
maintenance bypass to both input sources
- Hot-swap
electronics
|
| DB
Power |
UPS
Systems |
Server
rooms, communication equipment, industrial equipment
|
Upto
120 kVA |
-
High conversion efficiency
- Sinewave
control
- High
frequancy Inverter using IGBT
- Precise
and accurate output voltage control
- Wide
input supply range
- Efficient
battery charging
|
DB
Power Electronics Pvt Ltd.,
DB House, Mundhawa Road,
Pune 411 036, Maharashtra,
India.
Tel. 9520 - 670775, 670091, 671858
Fax. 9520 – 672374
E-mail: db.pune@dbelectronics.
sprintrpg.ems.vsnl.net.in |
* The features mentioned in the
table are based on brochures and inputs provided by
respective vendors. Network Magazine recommends IT Managers
to conduct their own conclusive tests before making
a buying decision.
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