Sine Wave UPS

Today demand of pure sinewave inverter/UPS is increasing beacuse square wave UPS/Inverter can not run various equipments. So we have taken a sinewave UPS for testing. 

We can know the purity of sine wave inveter by harmonics analysis. A square wave inverter has very high voltage THD at output whereas pure sinewave has zero THD(Ideal). 

UPS Harmonic Test Report

Date : 11-11-2014

Standard

UL1778 article 49 Harmonic Distortion Test

Instrument Under Test

UPS 600VA

Company Name

Sukm

Rated Voltage and Load

12V,50A

Battery Type

Tubular Battery

Test Condition

On battery source (Assuming full charge battery)

 

Load Pattern-

On 10% Load

Load Condition

Voltage

Voltage Harmonics

55.38 VA

227 V

2.843%

Voltage Harmonics Spectrum of UPS on 10% Load by SPEA-1

Comments –  

  1. Vthd is 2.843%.
  2. Fundamental harmonics is 99.9 % of Vrms which is good.
  3. Third harmonics is 2.2%
  4. From 5th to 13th harmonics are  less than 1% of Vrms.
  5. Other harmonics are zero.

On 20% Load

Load Condition(VA)

Voltage

Voltage Harmonics

124.78

227.3

2.611

Voltage Harmonics Spectrum of UPS on 20% Load by SPEA-1

Comment –

  1. Vthd is 2.611%
  2. First harmonics remain same on 99.9%.
  3. Third harmonic is also same on 2.2%.
  4.  15 to 25 harmonics are slightly increases.
  5. Others are zero.

On 25% Load

Load Condition(VA)

Voltage

Voltage Harmonics

153.9

226.3

2.755

Voltage Harmonics Report for UPS on 25% Load generated by SPEA-1

Comment –

  1. Vthd is 2.755%.
  2. Fundamental harmonic is remain same.
  3. Third harmonic increased by 0.1%.
  4. Others are same as previous.

On 40% Load

Load Condition(VA)

Voltage

Voltage Harmonics

194.53

223.6

2.835

Voltage Harmonics Report of UPS on 40% Load generated by SPEA-1

Comment –

  1. Vthd is 2.835%.
  2. Third harmonic is again increased by 0.1%.
  3. 5th to 17th harmonics are slightly increased.

On 50% Load

Load Condition(VA)

Voltage

Voltage Harmonics

302.8

222.8

3.596

Voltage Harmonics Report of UPS on 50% Load generated by SPEA-1

Comment –

  1. Vthd is 3.596%
  2. Third harmonic is also increased by 0.7 %.
  3. Harmonics from 5th to 15 are also increased.
  4. Others are zero.

Summary –

  1. UPS showing overload on load over 300VA.
  2. As load increases THD increases.
  3. At load above 50% THD is greater than 3.
  4. 3rd harmonic is affected most (0.9% change).

Testing Instrument – SPEA-1

Test Done By – Himanshu Sharma (Electronic Testing)

Harmonics Spectrum Report for UPS by SPEA-1

Download Harmonics  Spectrum Report

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(Updated: December 10, 2018)