FAQ

Q:

What is a Power Inverter?

A:

It is a device that converts electrical power from DC voltage to AC power.  Its typical application is to convert battery voltage into conventional AC voltage allowing you to use critical load when an AC power source is not available.

Q:

What does a Power Inverter do?

A:

A power inverter changes DC power from a battery into conventional AC power that you can use to operate all kinds of devices ... electric lights, kitchen appliances, microwaves, power tools, TVs, radios, computers, to name just a few. You just connect the inverter to a battery, and plug your AC devices into the inverter ... and you've got portable power ... whenever and wherever you need it.

Q:

What can I use one for?

A:

The inverter draws its power from a 12 Volt battery (preferably deep-cycle), or several batteries wired in parallel. The battery will need to be recharged as the power is drawn out of it by the inverter. The battery can be recharged by running the automobile motor, or a gas generator, solar panels, or wind. Or you can use a battery charger plugged into an AC outlet to recharge the battery.

Q:

What is the difference between a modified sine and pure sine wave inverter?

A:

 Modified Sine Wave:
The most common, general-use inverters available are of the "Modified Sine Wave" variety, usually available at more moderate pricing compared to pure sine wave models.  Although designed emulate a Pure Sine Wave output, Modified Square Wave inverters do not offer the same perfect electrical output. As such, a negative by-product of modified output units is electrical noise, which can prevent these inverters from properly powering certain loads.

 Pure Sine Wave:
Pure Sine Wave inverters provide electrical power similar to the utility power you receive from the outlets in your home or office, which is highly reliable and does not produce electrical noise interference associated with the other types of inverters. With its "perfect" sine wave output, the power produced by the inverter fully assures that your sensitive loads will be correctly powered, with no interference. Some appliances which are likely to require Pure Sine Wave include computers, digital clocks, battery chargers, light dimmers, variable speed motors, and audio/visual equipment. If your application is an important video presentation at work, opera on your expensive sound system, surveillance video, a telecommunications application, any calibrated measuring equipment, or any other sensitive load, you must use a Pure Sine Wave inverter.

Q:

What is a UPS?

A:

Q:

How many Types of UPS System?

A:

 On line UPS System

 Line Interactive UPS System

A UPS containing an off-line inverter that must transfer on during a blackout, but provides
faster transfer times than an off-line UPS. Power conditioning and surge suppression are
provided to protect the connected load.

 Off line UPS System

A UPS type which feeds power to the load directly from the utility and then transfers to battery power via an inverter after utility drops below a specified voltage. The delay between utility power loss and inverter startup can be long enough to disrupt the operation of some sensitive loads. Also called a standby UPS.

Q:

How to calculate UPS Size?

A:

When calculating the size of a UPS, it is important to take into account the following:
 Apparent power (VA or kVA) - This is defined as S=VxI for single-phase loads,
  S=(VLI x ILI)+(VL2xIL2)+(VL3xIL3) for three-phase loads where V is the
voltage, and I is the current absorbed by the load under normal operating conditions (EN50091- 1-1). This information can usually be found on rating hardware labels, and in the documents and information supplied with the system(s) to be protected. It is generally over estimated.
 Active power (W or kW) - Is defined as P=Sxpf where pf is the power factor. If
the value of P and pf of the load(s) are not specified, the power absorbed must be precisely measured in order to correctly size the right UPS. The typical load of a computer is associated with a pf of between 0.65 and 0.8. Active power is particularly relevant when sizing batteries.
 Overloads - Are voltage and current demands on the UPS in excess of its
specification. They may be temporary during initial energising of a system or constant where too much steady state load is connected to the UPS output.
 System Expansion - When sizing a UPS two factors are important. The reliability
of any electronic device is improved when run at less than 100% of capacity. For UPS the load should be around 90% of the system size to guarantee long-term reliability. A factor should also be added for future expansion of the protected load(s). This is typically taken as 25%.
 High switch on current demands - At power-on, some loads have a high initial
switch on current demand lasting for a short time period (50 to 100ms). For example laser printers, some types of lights, isolation transformers and pumps. For these types of load it is good practice to oversize the UPS by a factor of at least 3 or remove them from the protected system, especially when they can be allowed to power down on mains failure.

Q:

What is UPS in Parallel And Redundant Configuration?

A:

In network, enterprise wide and industrial installations, UPS may be connected in parallel or redundant configurations:
 Parallel - To obtain a kVA/kW output higher than that of any single UPS. For
example 2 x 200kVA modules may be connected in parallel to achieve a 400kVA output.
 Redundancy - To improve the overall UPS system resilience by applying the
principle of N+1. Here 2 x 200kVA modules may be connected in a redundant configuration to supply up to 200kVA. Should one module fail or be taken out of service for maintenance the remaining module is sufficiently sized to power the load(s).

Q:

What is APC?

A: