- Two 40 kVA 1 - phase transformer are connected in open delta to supply a 230 V balanced 3 phase load. The total load that can be supplied without overloading either transformer will be
The rated secondary transfer current, I
_{2B}= 40 × 10^{3}/ 230 = 173.9 A

This also be load line current, therefore the load kVA is = √3 × V_{2B}I_{2B}× 10^{-3}= 69.28 A - A 900 kVA load is supplied by three transformer connected in delta - delta. The primaries are connected to a 2300 V supply line, while the secondaries are connected to a 230 V load. If one transformer is removed for repair then the currents in the high voltage side of the transformer is
In delta - delta operation, V
_{L1}and I_{L1}are the line voltage and line current respectively on HV side, S_{Δ - Δ}= √3 × V_{L1}I_{L1}

⇒ 900 × 10^{3}= √3 × 2300 × I_{L1}

∴ I_{L1}= 900 × 10^{3}/ √3 × 2300 = 225.9 A

Transformer current per phase on HV side, I_{p1}= 1 / √3 × line current = 1 / √3 × 225.9 = 130.4 A - Two single phase furnace working at 100 V are connected to a 3300 V, 3 - phase supply through scott connected transformer. If there is no transformation loss, then the current in the 3 - phase lines, when the power taken by each furnace is 500 KW at a p.f. of 0.8 lagging will be
a = 3300 / 100 = 33

For teaser transformer, P_{2t}= V_{2t}I_{2t}cosφ_{2t}

⇒ I_{2t}= P_{2t}/ V_{2t}cosφ_{2t}= 500 × 10^{3}/ 100 × 0.8 = 6250 A

Since,the 2 phase load is balanced, the 3 phase side is also balanced. For the mmf balance of the teaser transformer I_{A}× 2 / √3 × T_{s}/ T_{p}× I_{2t}= 2 / √3 × 6250 / 33 = 218.7 A

∴ |I_{A}| = |I_{B}| = |I_{c}| = 218.7 A - Two 40 kVA 1-phase transformer are connected in open delta to supply a 230 V balanced 3 phase load. The total load that can be supplied without overloading either transformer will be
The rated secondary transfer current, I
_{2B}= 40 × 10^{3}/ 230 = 173.9 A

This also be load line current.

Therefore the load kVA is = √3 × V_{2B}I_{2B}× 10^{ - 3}= 69.28 kVA. - A 900 kVA load is supplied by three transformer connected in delta - delta. The primaries are connected to a 2300 V supply line, while the secondaries are connected to a 230 V load. If one transformer is removed for repair then the currents in the high voltage side of the transformer is
In delta - delta operation, If V
_{L1}and I_{L1}are the line voltage and line current respectively on HV side, S_{Δ - Δ}= √3 × V_{L1}I_{L1}

⇒ 900 × 10^{3}= √3 × 2300 × I_{L1}

∴ I_{L1}= 900 × 10^{3}/ √3 × 2300 = 225.9 A

Transformer current per phase on HV side, I_{p1}= 1 / √3 × line current = 1 / √3 × 225.9 = 130.4 A.

Design with by SARU TECH