Faq: Solar Inverter

FAQ or Knowlege center

UPS Releted FAQ´s

What is a UPS?
UPS is a power supply system with energy storage which ensures a permanent supply of the load in case of a supply voltage breakdown.

What is the difference between “KVA rating” and “KW rating” of UPS?
The mathematical relation is kW= kVA *pf. where kW is active or useful power and kVA is the vector sum of active power and reactive power. The equation therefore is kW= kVA *pf

What is the Input Power Factor (p.f.) of the UPS at different loads?
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.

How much is the static switch transfer time (Break in output) in Asynchronous and Synchronous mode if inverter fails?
In synchronous mode this break is less than 5 ms because of Static Switch in output and Inverter is in phase and frequency locked with Bypass. In case of Asynchronous mode it is between 15-20 ms.

What are the types of load applied to UPS during testing?
Resistive load and non linear load for normal testing and Inductive load on special request of inspection authority.

What happens if UPS fans fail?
Fans are provided for cooling of wire wound components as well as cooling of heat sinks. If these fans fail, internal temperature of the unit will increase and when the heat sinks temperature rises above 850 degrees Celcius it will give indication of ‘Over Temperature’. If this condition persists, Inverter will be switched off after 3 Minutes.

Is UPS output isolated from its input?
Yes, double wound isolation transformer of full load UPS rating is used at inverter output, which ensures complete isolation from input.

Can the UPS output neutral be earthed?
Yes, provided bypass isolation transformer is used or the operation of static switch is permanently disabled.

How to monitor an UPS in network?
SNMP Card along with Software can be used to monitor UPS in network.

What are advantages of Isolation?
Isolation ensures all impurities at supply input are filtered & not allowed to reach load.

Inverter Releted FAQs

What is an inverter?
An inverter takes DC power (battery or solar, for example) and converts it into AC “household” power for running electronic equipment and appliances.

Why are they called inverters?
Originally converters were large rotating electromechanical devices. Essentially they combined a synchronous ac motor with a commutator so that the commutator reversed its connections to the ac line exactly twice per cycle. The results is ac-in dc-out. If you invert the connections to a converter you put dc in and get ac out. Hence an inverter is an inverted converter. For more information about such converters see.

How can an inverter be used?
With a large enough battery bank, almost anything within reason can be operated from a power inverter – this assumes that the inverter has the proper power output for the given load. Everyday appliances such as microwaves, power tools, TVs and VCDs, lights, audio/visual equipment, battery chargers, tube lights ,Fans and computers are common loads. An inverter sized for loads with heavy inrush current can be used to power air compressors, water pumps, heaters, ventilation fans, and air conditioners Kevin Pure Sine Wave inverters\Home UPS are ideal for running sensitive test equipment such as communications equipment, oscilloscopes, scales, high end stereos & video equipment, communications equipment, etc.

What is Sine wave ?
It is the ideal waveform for the transfer of AC power. There are two types of waveforms available. A “modified sine wave”, and the “true sine wave”.
Modified Sine Wave – The modified sine wave is not really a sine wave at all. It is more less a “stepped wave”. It achieves voltage regulation by varying in width according to the battery voltage and the load. Thus, the wave is not as smooth as a sine wave. The quality of modified sine wave inverters should not be underestimated. They are highly capable, and (by narrowing the waveform) they save energy when running only small loads, as happens during most of the day in a typical home. Modified sine inverters have been successful in many thousands of remote home, RV and marine systems since 1986.
True Sine Wave – Also known as Pure Sine Wave, is the most reliable waveform and provides power almost identical to a standard wall outlet. The power produced fully assures that your “sensitive loads” will be correctly powered, with no interference. Some appliances are likely to require Pure Sine Wave including digital clocks, battery chargers, light dimmers, variable speed motors, and audio/visual equipment. For these reasons, true sine wave inverters can be more a more expensive choice.

Why do I hear buzzing on my stereo when using a modified sine wave inverter?
Some inexpensive stereos use power supplies that cannot eliminate common-mode noise. These would require a sine wave inverter to operate noise-free.

How do I know which inverter to buy?
Different devices require specific wattages to run correctly and efficiently. Please use this easy formula to determine the correct size inverter:
AMPS x 220 = Watts
Example: 10 Amp Unit X 220 = 2200 Watts

What is the Low Voltage Alarm & Shutdown?
The low voltage alarm will sound when the DC source falls below 10 Present and the automatic shutdown will power off the inverter. This is done to save your battery(ies) so you can restart your vehicle.

Is my inverter weatherproof?
No. Treat your inverter like you would your TV. You wouldn’t put your TV outside in the rain, please don’t leave your inverter there either. Be aware of lighting storms. If struck, your inverter would go into a permanent overload state and may even smoke it. If using in a marine environment, try to keep it tucked away underneath, in a dryer area.

How do I charge the battery for my inverter?
Because inverters operate from a DC (Direct Current) power source, usually a battery bank (one or more batteries), the battery source will have to be recharged at some point. (Remember that a battery discharged more than 80% is probably close to being dead.) Depending on the inverter load and run-time required, most power applications will be covered by the charged battery. If the load is large (air conditioner, large draw power tools, large microwave, food freezer, ice cream machine, etc.), the user should verify that the installed inverter is of large enough capacity to operate this power requirement.

Battery installation tips.

  1. Connect high amperage accessories such as a winch to the top terminals only. Do NOT use the side terminals.
  2. Replace any cables and connectors that have corrosion, rust, or other damage.
  3. Do not install batteries in a non-ventilated or sealed compartment.
  4. Do not lift or handle the batteries by the terminals.
  5. Do not over tighten terminal bolts.
Load Charts
1 Ceiling Fan 80 Watts Per hrs
2 4ft Tubelight 40 Watts Per hrs
3 CFL Blub 20 Watts Per hrs
4 TV 150 Watts Per hrs
5 Fridge 165 L 150 Watts Per hrs
6 Fridge 265 L 200 Watts Per hrs
7 Laptop 60 Watts Per hrs
8 PC 150 Watts Per hrs

Load Charts

  650 VA/12VA 850 VA/12VA 1450 VA/24VA
Applications A B A B A B
Fan 3 2 4 3 8 7
CFL 3 2 5 4 9 8
TV 1 - 1 - 1 -
Computer - 1   1 - 1