3 PH to 1 PH Transformer, 12 KVA, P/N 6411LA, Rev A

3 PHASE TO 1 PHASE TRANSFORMER

(TEST AND ANALYSIS)

A 3 PH to 1 PH transformer was constructed as shown in the photograph below:

The schematic of the transformer and the test set up are shown in Figure 1. An open delta is connected to an open wye with middle coil missing. Thee phase power is applied at (2, 5, and 1/6).

The following tests were performed by L/C Magnetics:

Test 1:

• No load test. 
• Input voltages are 210 VAC, 3 PH, 60 Hz 
• Output voltage measured is 210 VAC, 1 PH, 60 Hz 
• Excitation current IA = 0.5 A 
• Excitation current IB = 0.5 A 
• Excitation current IC = 0.5 A 
• V1,2 = 210 VAC approx 
• V5,6 = 210 VAC approx 
• V2,5 = 213 VAC approx 
• V7,8 = 211 VAC approx 
• V3,4 = 211 VAC approx 
• V4,8 = 365 VAC approx 
• SUMMARY: 
• INPUT IS 210 VAC, 3 PH. 
• OUTPUT IS 210 x √3 = 363 VAC.

Test 2:

• 12.5 ohm load test 
• Input voltages are 212, 220, 228 VAC, 3 PH, 60 Hz approx. 
• Output voltage measured is 360 VAC, 1 PH, 60 Hz 
• V 4,8 = 360 VAC approx 
• V 4,3 = 206 VAC approx 
• V 7,8 = 220 VAC approx 
• Line current IA = 29.4 A approx 
• Line current IB = 57 A approx 
• Line current IC = 28.5 A approx 
• ID = 28.5 A 
• SUMMARY: 
• INPUT IS 210 VAC, 3 PH, 60 Hz. 
• OUTPUT is 360 VAC. IB IS TWICE AS MUCH AS IA OR IC 

Test 3 set up is shown in Figure 2 below:

Test 3:

• No load test. 
• See Figure 2, V 4,8 = 210 VAC, 1 PH, 60 Hz 
• V 3,4 = 105 VAC approx 
• V 7,8 = 105 VAC approx 
• V 1,5 = 105 VAC approx 
• V 1,2 = 105 VAC approx 
• V 2,5 = 1.1 VAC approx 
• SUMMARY: 
• INPUT POWER IS 210 VAC, 1 PH, 60 Hz. 
• OUTPUT POWER IS NOT 210 VAC, 3 PH, 60 Hz. 
• THE TRANSFORMER DOES NOT WORK AS 1 PH TO 3 PH TRANSFORMER.