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The demand of “Sine Wave UPS/Inverter”

Considering the unsuitability of Square Wave and Modified Square/ Quasi Sine/ Modified Sine Wave UPS/ inverters for most of the Electrical/ Electronic Appliances, the demand of Sine Wave UPS/ Inverter, which can provide the good quality of power to all Electrical/ Electronic Appliances. Using sine wave UPS/ Inverter, we can get same performance of sophisticated Electrical/ Electronic Appliances as on Mains Grid Power. Also on Sine Wave UPS/ Inverter, service life of sophisticated Electrical/ Electronic Appliances do not deteriorate.

In above two major types, Sine wave inverters are superior in quality and performance. It doesn’t mean square wave inverters are inferior, square wave or modified sine wave inverters have their own specialties. But the fact, all of us should accept is ‘sine wave inverters are better than square wave or modified sine wave inverters’.

The Sine Wave Technology

To get the Pure Sine Wave at the output of the UPS/ Inverter, advance technology has to be used. To generate Pure Sine Wave, Advance Digital Signal Processing (DSP) Technology is required, for that DSP chip is being used now a day. DSP Chip along with dedicated hardware and software using high frequency PWM Technology used to produce Pure Sine Wave at the output. A special dedicated algorithm also used to control the charging the Power Battery smartly using the same DSP chip. It enhance the battery life significantly up to 1.5 times.

The efficiency of the Sine wave UPS

Not actually, it depends upon the design and technology. But because of market pressure of reducing the cost of UPS (to make the UPS most competitive), less efficient transformer is being used in the UPS causes less overall efficiency. By using efficient transformer, the efficiency of DSP based Sine wave UPS can be increased. EAPRO is using Copper Transformer to make the UPS more efficient.

Sine wave UPS gives extended power back up compared to modified sine wave of square wave inverters. It saves your current bill.

What are the advantages of Sine wave UPS over Square Wave/Modified Square Wave/Trapezoidal Wave/Quasi Square/Modified Sine Wave UPS?

Square wave UPS/ Inverters are First generation UPS/ Inverters. These are cheapest inverters available in the market. Modified Square wave/ Trapezoidal wave/ Quasi Square/ Modified Sine wave UPS little costlier than the square wave UPS. But Sine wave UPS/ Inverter are best in performance and also in the same price band as Modified Square wave/ Quasi Square/ Modified Sine wave UPS.

Square wave UPS/ Inverters are VERY noisy. OK for apps like lighting, heating, running motors etc. only, while Quasi Square/ Modified Sine wave UPS are having little less humming noise but less efficient in comparison to Square and Pure Sine Wave Inverter/ UPS. But Sine wave UPS/ Inverter widely recommended and suitable for all type of AC equipments (Home appliances/ PCs/ Motors/ lifts etc.). The output of Sine wave UPS/ Inverter is similar to Main Grid Power. It does not produce any Noise. Sine wave UPS/ Inverter is completely appliance friendly as the power produced is similar to Mains Grid Power.

Sine wave inverters are the best. They utilize sinusoidal PWM to produce a CLEAN sine wave which is equivalent to Mains Grid Power. The circuitry of Sine wave UPS is a lot more complex than the square wave, but because of very less distortion, it doesn’t produce any humming noise. Most sensitive equipment like Wi-Fi’s, PC’s, medical equipment etc. can be connected to Sine Wave Inverter/ UPS. You can operate Mixie or Grinder safely with sine wave inverters. (850 VA inverters and above)

Inrush/ Surge Current

Inrush current, input surge current or switch-on surge refers to the maximum, instantaneous input current drawn by an electrical device when first turned on. For example, incandescent light bulbs have high inrush currents until their filaments warm up and their resistance increases. Alternating current electric motors and transformers may draw several times their normal full-load current when first energized, for a few cycles of the input waveform.

Crest Factor

The crest factor and the peak currents of a load are important considerations in power source selection. Crest factor is defined as the ratio of peak value to rms value of a current waveform

Crest Factor = Peak current in Ampere / RMS Current in Ampere

The crest factor for a sinusoidal current waveform, such as that which a pure resistive load would draw, is 1.414 since the peak of a true sinusoid is 1.414 times the rms value. However, the crest factor for a non-sinusoidal current waveform can differ dramatically for loads that are not power factor corrected, such as a switching power supply or lamp ballast, which give a current waveform that is short in duration but high in amplitude.

Efficiency of UPS

The ratio of the UPS output power to the UPS input power is called efficiency of UPS/ Inverter. The UPS efficiency varies depending on its load factor.

% Efficiency = [UPS output power (in kVA) ÷ UPS input power (in kVA)] x 100

Generally, 85% efficiency is considered as Standard, 90% efficiency is considered as Good and >95% efficiency is considered as Best efficient UPS.

Distortion of UPS

Total Harmonic Distortion is an important factor while selecting a suitable UPS based on its application. It is a measure of the ratio between the fundamental and the harmonics that are present in a waveform.

The presence of harmonics in AC voltage waveform changes its wave shape from a simple sinusoidal to complex waveform. Distortion in the output Sine Waveform, generally transmitted by non-linear loads (like Computers, Switch Mode Power Supplies, Variable Speed Motors and Drives, Copiers and Fax Machines etc.).

A Sine Wave UPS/ Inverter has AC Harmonic content (THD-Voltage) <= 3% for linear load and <=5% for non linear load.

Why noise is produced in the appliance when running on Square/Modified Square Wave/Trapezoidal Wave/Quasi Square/Modified Sine Wave Inverter/UPS?

Because of presence of High level Harmonic Distortion in square /Modified Square wave/ Trapezoidal wave/ Quasi Square/ Modified Sine wave Inverter/ UPS, all the non-linear loads like fans, electronic blast of florescent lights, Switch mode power supplies, variable speed motors and drives, copiers and fax machines create humming noise.

Few Facts
Some company claims for Trapezoidal wave UPS/ inverter, but it is actually a Modified Square wave/ Quasi Square/ Modified Sine wave UPS/ Inverter. Some company promote their product as Modified Sine Wave, some promote as. But the fact is all these type of Inverter generate same output wave, which is Quasi Square Wave, which is inferior than Pure Sine Wave in all respect.

Comparision Table

Parameters

Square Wave UPS

Modified Sine Wave/ Modified Square Wave/ Quasi Wave UPS

Sine Wave UPS

Remarks

Technology

Crude Technology

Moderate Technology

Adv. DSP based PWM Technology

(20 KHz Switching Freq.)

Audible and electrical Noise

Very High

High

No Noise

Noise is harmful for the life of the appliance.

Suitable for Sophisticated Electrical appliance

Not suitable

Not Suitable

Suitable

Pure Sine Wave supply is most suitable for any electrical Appliances.

Total Harmonic Distortion (THD)

Very High

High

Low

(< 3% on Resistive Load)

High Distortion is harmful for the life of the appliance.

Crest Factor

(Capability to Handle Inrush/ Surge Current)

Very Low

Very Low

Good

(3 : 1)

Good Crest Factor beneficial for Inductive/ moterised load

(Electronic blast of tube light, SMPS, Motor Drives etc.)

Efficiency

Upto 80%

< eff. of Square Wave UPS

85 to 88%

More energy efficient means money saving

Application of Different types of Inverters/UPS

Square Wave Inverter/UPS

  • Incandescent Bulbs
  • Fluorescent Light (with Humming noise)
  • Domestic Fans (with Humming noise)

Modified Sine Wave/Modified Square Wave/Quasi Square Wave/Trapezoidal Wave Inverter/UPS

  • Incandescent Bulbs
  • Fluorescent Light (with Humming noise)
  • Domestic Fans (with Humming noise)

Sine Wave Inverter/UPS

  • Incandescent Bulbs, Compact Fluorescent Light, Fluorescent Light, Domestic Fans etc.
  • Personal Computers, Servers, Printers and other IT equipments.
  • Air Conditioner
  • Refrigerator, Water Pump, Induction Motor
  • Induction Cooker
  • Compact Fluorescent Light
  • Television, Microwave Oven, Washing Machine, Heater/Geyser
  • 3-Ph Lift Motors

High Frequency Sine Wave Inverter/UPS

  • Switch Mode Power Supplies, Variable Speed Motors and Drives, Copiers and Fax Machines etc.
  • Transformer
  • Incandescent Bulbs, Compact Fluorescent Light, Fluorescent Light, Domestic Fans etc.
  • Personal Computers, Servers, Printers and other IT equipments.
  • Air Conditioner
  • Refrigerator, Water Pump, Induction Motor
  • Induction Cooker
  • Television, Microwave Oven, Washing Machine, Heater/ Geyser
  • 3-Ph Lift Motors

Advantages of Sine Wave Inverter

  • Simple, the square wave inverters are built old technology whereas pure sine wave inverters built with State Of The Art Technology.
  • In Sine wave inverters, the fan or tube lights won’t make any humming noise.
  • Sine wave inverters gives the same current which you get from power grid whereas square wave inverters gives the current with different wave form that is not safe for motors, induction applications, sensitive electronic devices.
  • Output voltage from sine wave inverters is with in the 230 volts limit whereas square wave inverters output voltage may touch 290 volts.
  • Some branded stabilizers and compact computer UPS won’t accept the wave form of square wave inverters, in such case the TV stabilizers or computer UPS need to be bypassed or removed to continue using the TV or Computers with square wave inverter. You don’t need to face such a problem with pure sine wave inverters; they operate seamlessly with any type of stabilizers and compact computer UPS.
  • You don’t need to purchase a separate UPS for your desktop computer as Sine wave inverters take care of your pc like a dream.
  • Sine wave inverters gives extended power back up compared to modified sine wave of square wave inverters. It saves your money.
  • You can operate Mixie or Grinder safely with sine wave inverters. (850 VA inverters and above)

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