1.
What is the difference between "KVA
rating" and "KW rating"
of UPS?
Ans. The equation is kW= kVA *pf.
In general kW is active or useful
power and kVA is the vector sum of
active power and reactive power. The
equation is kW= kVA *pf.
2.
What is the Input Power Factor (p.f.)
of the UPS at different loads?
Ans. Power factor is a function of
phase displacement angle between voltage
and current and distortion factor.
It is calculated as a ratio of real
power to apparent Power drawn by load.
PF is low at lower loads and goes
on improving at higher loads. PF is
also lower at higher input voltage
and goes on improving as voltage reduces.
Input Power Factor is independent
of type of load for double conversion
technology.
For nonlinear loads the power factor
is low due to the presence of high
percentage of harmonics present in
the load current.
3.
How much is the static switch transfer
time (Break in output) in Asynchronous
and Synchronous mode if inverter fails?
Ans. In synchronous mode this break
is less than 5 mS because of Static
Switch in output and Inverter is phase
and frequency locked with Bypass.
In case of Asynchronous mode it is
between 15-20 mS.
4.
What is the maximum rating of the
UPS offered by ENP ?
Ans. 400kVA Single module capacity.
Six such modules can be paralleled
for expansion up to 2400 kVA or for
redundancy
5.
How to arrive at correct UPS capacity
for a given load?
Ans. Estimate steady state ( normal
running ) kVA of the total load. Determine
inrush kVA of the largest load in
the total load distribution. The rated
kVA capacity of the UPS should be
85% of the sum of above two [Steady
state kVA + Inrush kVA].
This is under the assumption that
all loads are not switched on at the
same instant and largest load is started
while all remaining loads are running
6.
What is the % total harmonic distortion
(%THD) of the UPS output voltage and
how it is measured?
Ans. Total Harmonic Distortion is
measured using Distortion meter. For
linear load it is less than 1% typical
and less than 2% maximum. For nonlinear
load with crest factor 3:1 it is less
than 5%.
7.
What is the overload capacity of the
UPS?
Ans. 110% for 60 minutes 125% 10 minutes
150% 60 seconds
Maximum fault current under short
circuit will be less than 200% of
rated current.
8.
What is the type of load applied to
UPS during testing?
Ans. Resistive load and non linear
load for normal testing and Inductive
load on special request of inspection
authority
9.
What happens if UPS fans fail?
Ans. Fans are provided for cooling
of wound components as well as cooling
of heat sinks. If these fans fail
internal temperature of the unit will
increase and at heat sink temperature
of 850 C it will give indication of
'Over Temperature'. If this persists
then Inverter will be switched off
after 2.5 Minutes
10.
What is the degree of protection (IP
protection) applicable for ENP UPS?
Ans. IP 20 even with front door open.
IP 31 on special request.
11.
Is UPS output isolated from its input?
Ans. Yes, double wound isolation transformer
of full load UPS rating is used at
inverter output, which ensures complete
isolation from input.
12.
Can the UPS output neutral be earthed?
Ans. Yes, provided bypass isolation
transformer is used or the operation
of static switch is permanently disabled.
13.
What type of UPS ENPIL is manufacturing?
Ans. On line UPS
14.
What is burn in test? How much duration
the heat run of standard UPS is carried
out ?
Ans. Burn in test means UPS kept in
running condition at some load or
at no load. (Burn in) test at full
load and for minimum 8 hours is carried
out on every UPS
15.
Why there is no alarm or indication
for any fan failure?
Ans. Fan failure is not directly indicated
because on failure of fan heat sink
temperature of UPS will increase and
this rise is depends upon percentage
of load on UPS. Fan failure indirectly
indicated as 'Over temperature'.
16.
Does ML 3.0 send traps to SNML1.5
client?
Ans. Yes, ML 3.0 can be used to send
traps to existing ML1.5 clients. What
you need is network shutdown license
for those many clients where you want
to send traps.
17.
How Netcom can be used to send trap
to Workstations in the network?
Ans. Netcom provides you an option
to send traps to twenty workstations
in your network. One of which could
be your NMS
18.
How do I monitor UGXT UPS from some
remote location in the Network?
Ans. Hookup UPS to network via our
SNMP agent called Intellislot, Load
either ML1.5 or ML3.0 on one of workstation
in your network to receive traps from
UPS or install SNMP manager on NMS.
19.
I am using UPS model as PSP and is
interested in auto shutdown of workstations,
how to go about the same?
Ans. PSP UPS can also be used to provide
auto shutdown facility
20.
Do you offer shutdown of multiple
workstations
Ans. Yes
21.
What is the difference between the
software SiteNet1 and Multilink auto
shutdown software's?
Ans. SiteNet1 is primarily used for
standalone configuration while MultiLink
is used for Network configuration
based on SNMP protocols
22.
What is the difference between the
multi port and multi Link?
Ans. Multiport is a device used to
hookup more than one workstation to
one UPS, while MultiLink is a software
used to carry out auto shutdown of
one or multiple workstations using
Network Shutdown license
23.
Do I need to install any client software
(Package) to monitor the UPS parameters
while using Netcom?
Ans. No , only web Browser is required
24.
Can I send a message on pager about
the status of UPS automatically on
any event that occurs on the UPS?
Ans. Yes, the option is available
in Sitenet1 , SiteNet2 and ML3.0 s/w
25.
Can I run any scripts on certain events
before the shutdown of the OS?
Ans. Yes, SiteNet1 , SiteNet 2 and
ML3.0 as well as ML 1.5 prompts you
an option to run any script before
OS shutdown.
26.
Do you offer shutdown software for
linux operating system?
Ans. Yes, MultiLink 1.5 and MultiLink
3.0 softwares are compatible with
following Linux for Intel, 2.2-2.4
Kernel: Red Hat Linux 7.0,7.1 Caldera
Systems,Inc. OpenLinux 2.4,3.1 SuSE
Linux 7.1,7.2
27.
Do you offer shutdown software for
windows 2000?
Ans. ML3.0 and ML1.5 software's provides
auto shutdown for windows 2000.
28.
How to monitor S7400M UPS in network?
Ans. Netcom can be used to monitor
S7400M UPS in network
29.
Why do ENPI PEC systems use Electric
reheaters?
Ans. When temperature conditions are
achieved and Relative humidity (RH)
has to be achieved, the A/c system
goes on to a dehumidification cycle.
During de humidification cycle (De-hum)
if any of the electronic equipment
is switched OFF or dehumidification
cycle is called for at night, when
the load on the A/c is partial, along
with dehumidification there will be
a drop in temperature. Since temperature
is to be controlled within ±
1°C and RH is dependent on temperature,
the heater will come ON to compensate
for the sensible heat loss in the
room so that the temperature is maintained
during dehumidification cycle. Therefore
ENPI A/c used heaters only for Sensible
Heat Compensation. ENPI used Electric
reheat for sensible heat compensation
only. The heater will come ON only
if the load goes down to 30% of the
design load i.e. of the load in the
Telephone exchange goes below 9.0
TR where 30TR working + 10TR standby
system is installed. This situation
will never occur in places like Mumbai
etc. but only possible only where
extremely low ambient conditions prevail
like in Delhi and Northern part of
India. The heaters are of low watt
density and highly efficient through
Fin tubular design and hence is optimized
on energy consumption. Hot gas reheat
is an old method of providing heating
during dehumidification cycle. ENPI
control temperature and RH simultaneously,
since they are inter-related (For
your information the approximate relationship
is 1°C increase will be 3% RH
decrease and vice versa approximately
as per pyschorometer chart) ENPI microprocessor
controller with the PID logic for
temperature and Dew point logic for
RH have simultaneous control on these
two parameters resulting in optimization
of power. This is built through an
Algorithm in the Microprocessor as
follows: RHadj = RHact + 3 (Tact -
Tset) All other Microprocessor Controllers
available do not have this feature
of SIMULTANEOUS control on temperature
and humidity but have Sequential control
of Temperature and humidity. This
means, Temperature is controlled 1st
and then RH is controlled. When temperature
reaches set point and RH is not achieved,
the unit goes on to dehumidification
cycle. As a result of dehumidification,
the supply air temperature reaches
lower temperature and hence requires
heating to bring it to normal temperature.
Due to this heating the temperature
in the room goes higher. This follows
a cycle of cooling and heating to
achieve the desired level of temperature
and RH. When there is a sequential
process of control of Temperature
and RH, there is excessive power consumed
through continuous heating. To optimize
on this power, the principle of Hot
gas reheat comes into picture. Hot
gas reheat feature uses the waste
heat from the Compressor that would
have otherwise been rejected by the
condenser into the atmosphere, to
heat the air during the dehumidification
cycle. So, this feature is not required
in ENPI sort of systems which have
a better logic of Microprocessor and
has inbuilt power saving features.
Hot gas reheat saves power from the
additional power being spent and hence
is not an optimal process. There are
no solutions for the following situations
when Hot-gas reheat is used as a feature:
1. Heating as elaborated in the text
is to bring back temperature into
control band in part load conditions.
If in Delhi, during winter, if the
ambient temperature drops to 5°C
or 10°C and there is part load
condition in the exchange, to control
the temperature one would require
heating process. In this a system,
which has Electric reheat, will function
in the heat mode and achieve the desired
condition. If there is a HG reheat
feature, the compressor has to come
ON for the HG reheat to operate. This
will mean part cooling and part heating.
This is a wasteful & slow process
not benefiting the user at all. There
are no explanations to this question
by the firm who have propagated this
feature. 2. The HG reheat coil acts
as an additional resistance to the
air flow and hence adds to the load
of the Fan motor resulting in higher
power consumption of the Fan motor.
3. The HG reheat coil is placed very
close to the Cooling coil in the design
of the systems. This results in serious
maintenance problems since the inner
portion of the HG reheat coil and
outer portion of the Evaporator coil
beneath the reheat coil can never
be cleaned and hence deteriorates
the efficiency of the Air-conditioning
unit itself. 4. Compressor throws
out oil along with refrigerant since
both are miscible. If oil accumulates
in the copper tubes of the HG Reheat
coil, this will result in efficiency
drop of the heat transfer resulting
in longer time for reheat. Hence HG
reheat feature in an air-cooled system
with long piping is a dangerous situation.
With all the above points in view,
we recommend removal of Hot Gas reheat
feature, which is not an energy saving
feature at all in our opinion.
30.
Please confirm if we can commit 18
deg +/- 1 deg C temperature control
and 50 +/-5 RH control with our PAHU
with CEMS 100 installed in a switch
room. Incase not possible, I would
require a technical reasoning also.
Ans. Normally, CHW temperatures are
in the range of 7 deg C. This corresponds
to 44.6 F of water temperature. There
is no way that the ADP can be anything
lower than this temperature. ADP shall
be around 8 deg C i.e.46.4 F. At 46.4F
ADP, the lowest room temperature (assuming
SHF of 0.95) that can be achieved
is 21 deg C and 50% RH Nothing lower
than that. If the entering water temperature
is 5.5 deg C, we can go down to 20
deg C, for which you need to take
Customer's opinion. Conversely, if
you want to achieve 18 deg C, there
is a remote possibility, without any
control on RH i.e. RH will be more
than 75%. Conclusion: Customer should
accept 22 deg +/- 1 deg C and 50%
+/- 5% RH with EWT of 7 deg C and
LWT of 12 deg C. If even competition
is claiming otherwise, we can prove
to Customer that this is not possible
psychometrically.
31.
What are the requirements for the
UGXT machine to be monitored on the
NMS?
Ans. You would be requiring the SNMP
hardware agent Intellislot with the
valid Tcp/Ip address and Ethernet
port along with the SNMP Manager for
specific NMS for more info click below
|
