I agree with Mark and others as to the potential cause of the VFD and transformer failure.
As far as the need for a transformer....it has to do with what is considered "safe" and economical. I have worked on machines that have had 480 volt starter coils (long, long time ago), as well as 240, 120 and 24 volt coils. It has to do with what voltages you want at the start-stop station. (Those push button switches have to be rated for the voltages you are working with). These days a lot of machine tool manufacturers use 24 volt coils and push buttons. That means there are lower (safer) voltages where the human operator interacts with the machine.
To the OP.....just remember not to use the generated leg of an RPC to tie into the transformer.
My 2cw
Chris
As far as the need for a transformer....it has to do with what is considered "safe" and economical. I have worked on machines that have had 480 volt starter coils (long, long time ago), as well as 240, 120 and 24 volt coils. It has to do with what voltages you want at the start-stop station. (Those push button switches have to be rated for the voltages you are working with). These days a lot of machine tool manufacturers use 24 volt coils and push buttons. That means there are lower (safer) voltages where the human operator interacts with the machine.
To the OP.....just remember not to use the generated leg of an RPC to tie into the transformer.
My 2cw
Chris