Sine Wave UPS

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

We can know the purity of sine wave inverter 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

Load Pattern-

On 10% Load

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

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

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

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

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)

Download Harmonics Spectrum Report