Star and Delta Winding Separately Connected ACS880
We have ACS880 2000KW Which have four Common Rectifier Inverter Modules. Drive is fed through a twelve pulse converter transformer. There are four drive modules in two sets, each set consisting of two modules and dc bus of all four modules are common. There are fuses between at common point of two DC buses of sets.
My question is that why its necessary to connect one set on star winding of transformer and other set to delta winding as shown in below drawing. Why cant we connect one module of each set to star winding and second module of other set on delta winding.
My question is that why its necessary to connect one set on star winding of transformer and other set to delta winding as shown in below drawing. Why cant we connect one module of each set to star winding and second module of other set on delta winding.
Asked 4 months ago
Answers
1
Hello,
The aim of 12-pulse configuration is reduction of harmonics emitted from drive to your network. Harmonics are reduced by superposition between two transformer secondary windings.
In your configuration there is a small DC voltage difference between the first and second set due to time delay in rectifier commutation at delta and star sets. Therefore there are installed DC fuses providing short circuit protection in case of higher DC voltage ripple at any of inverter sets.
I think , if you changed delta&star configuration, there could be too high current in unfused DC bus connections that can destroy capacitors.
The aim of 12-pulse configuration is reduction of harmonics emitted from drive to your network. Harmonics are reduced by superposition between two transformer secondary windings.
In your configuration there is a small DC voltage difference between the first and second set due to time delay in rectifier commutation at delta and star sets. Therefore there are installed DC fuses providing short circuit protection in case of higher DC voltage ripple at any of inverter sets.
I think , if you changed delta&star configuration, there could be too high current in unfused DC bus connections that can destroy capacitors.
Answered 4 months ago
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