RATIO TEST

Calculating the Specified Ratio:

If Star – Star Transformer: Ratio K = HV Specified voltage / LV Specified Voltage

If Delta – Star Transformer: Ratio K = 1.732 * (HV Specified voltage / LV Specified Voltage)

If Delta – Delta Transformer: Ratio K = HV Specified voltage / LV Specified Voltage

Procedure:

1. In Ratio Meter just rotate the dial and directly measure the value.

2. By apply separate voltage and measure using Meters.

i) Apply Single Phase/ phase to Phase/ All three phases as per availability. Measure the output.

ii) For easy reference apply 2 phase, that means 1st U & V,2nd V & W, finally W & U.

iii) The output must be V out = Applied voltage/ Specified Ratio (K)

Error:

Calculating the error is E = Specified Ratio ± Measured Ratio

( +) % Error = (100 * (Specified Value/Measured value)) – 100

( - ) % Error = (100 * (Measured value/ Specified Value)) – 100

Posted By: B.K, boopathymail@gmail.com, transtechindia33@gmail.com