# Secondary side of transformer

K

#### KG

I'm trying to get help with the secondary side of a industrial control XFMR. The primary side is 380V 1P. The secondary has two taps. One for 115V and one for 230V. I need to tap off of both. Do I ground one side of the 230V or leave it ungrounded. I know to ground the one side of the 115V side. If the one side of the 230V gets grounded can I connect the grounded side of the 230V to the grounded side of the 115V? Thanks for any help

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#### Ralph Kitts

I'm assuming that at this point, you have determined that you MUST ground these secondarys (it's not always mandatory/desirable --- ie. isolation) Anyway, it is likely that the 115V is a center-tap for the 230V coil. That being the case, grounding one of the 115V legs (probably the "outside" leg.....not the center-tap) would also be grounding one side of the 230V coil, so this would satisfy your question. Hopefully I've understood your question. Just draw it out, and if you're unsure, put a fuse in a line or two.

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#### Dharanisingh, Raja

You can ground both taps and connect them too.... Follow the diagram below. -----)(--------------------- )( 110V )(---------| )(---------|-----------| )( | )( ----- )( 230V -----)(---------------------

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#### RAUL BENCOMO

Hi KG, In the secondary of your transformer you can have two arrangements 1) One coil with three taps, X0, X1 and X3 and you will have 115 V X0-X1, 230V X0-X1 you can connect to ground the X0 and you will have the 115V and 230 V both grounded. 2) Two coils one for 115 V and other for 230V in this case you may connect any tap of each coil to ground, this is if you want your system grounded. In the number one if you ground one the X0 you will have grounded two system. In the second you may have grounded each coil separetely but remember there is only one ground in any system. I hope this will be helpful for you, in any case contact me again Raul Bencomo

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#### KG

thanks for the reply. the secondary of the transformer has two points for the 115v hookup and two separate points for the 230v side.now what? also do you add the VA for the 115v and 230v to come up with the total va requirement of the xfmr?thanks

K

#### KG

thanks for the reply. the secondary of the transformer has two points for the 115v hookup and two separate points for the 230v side.now what? also do you add the VA for the 115v and 230v to come up with the total va requirement of the xfmr?thanks