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#28471 - 08/19/03 09:07 PM Ground on a Transformer
Houston we have a problem Offline
Junior Member

Registered: 08/19/03
Posts: 2
Loc: Houston Texas
I work in a Welding shop and we have a machine that runs a pacemaster 1 pc board used to turn the head of the machine the board input is 115v and main power to the machine is 480 we installed a 480 to 120 transformer with the input H1 H2 H3 H4 output X1 & X2 I know 480V cross H2 H3 together input Leg 1 to H1 & Leg 3 to H4 now back to my 115v pc board Do I still ground X 2 to ground & still have a neutral ? We have blow the board twice also sometimes in welding the welding dc current will hit the machine will this cause my pc board to crash with X 2 to ground

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#28472 - 08/20/03 10:42 AM Re: Ground on a Transformer
rmiell Offline
Member

Registered: 11/09/00
Posts: 261
Loc: La Junta, Co. USA
Not to be offensive, but I am a little concerned whether or not you are a "qualified" person to do this work. From your wording I think perhaps not.

Transformer hookup need to be completed following the wiring diagram on the transformer, and all overload protection needs to be in place.

Most control transformers are required to be grounded, and connected to the neutral of the transformer. This is not the same as grounding of the unit, which should be done with a properly sized equipment grounding conductor, run with the supply lines.

You should get a qualified person to check out this installation. Those boards have to be too expensive to test out someone's knowledge (or lack of) on.

If I have this wrong, please forgive me.

Rick Miell

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#28473 - 08/20/03 02:49 PM Re: Ground on a Transformer
Houston we have a problem Offline
Junior Member

Registered: 08/19/03
Posts: 2
Loc: Houston Texas
Your right I'am just a helper I just found it odd that he did NOT ground the neutral on the transformer I just thought I would do a little diging on this. The transformer diagram does not show to ground the neutral but if he did would the DC current from the welding maching hurt the board as the welder runs about 400 amps DC ?? he has the output of the transformer fused before the PC board Hot & Neutral fused at 25 AMPS I'am just a helper but today ((( I ))) found out why the pc board was hit The 90 VDC motor the A 1 lead was grounding out in the motor lead box...... but I still have the question about the DC current of the welder if the transformer was grounded could it hurt the board ??? Or would you fuse the Ground ???? Give me about 10 Years and this will all be funny to me I'm sure as I know it is to you. I have the drive to learn all I can. One day I will walk with PRIDE

[This message has been edited by Houston we have a problem (edited 08-20-2003).]

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#28474 - 08/20/03 03:08 PM Re: Ground on a Transformer
Bjarney Offline
Moderator

Registered: 04/10/02
Posts: 2561
Loc: West-Southern Inner-Northeast ...
Equipment manufacturers typically have technical-support staff that can discuss field-configuration issues. That will tend to cut through speculation on operational modes and features. Without consulting them, there is little hope in understanding the intended operation of the equipment. If the subject gear has been listed and labeled, the NEC does not apply to internals, so it is not a good idea to perform modifications in the field unless given instructions to do so.




[This message has been edited by Bjarney (edited 08-20-2003).]

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#28475 - 08/22/03 11:18 PM Re: Ground on a Transformer
condenseddave Offline
Member

Registered: 03/30/02
Posts: 25
Loc: East Stroudsburg, PA USA
Don't fuse the ground.
_________________________
It's all about integrity.

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