> You are wrong. He must ground the tap where he gets the "neutral"
> and provide some type of fuse or circuit breaker protection on the
> "hot".
Not on your life! One never grounds the wiper of a variac (auto-
transformer). Connecting a 120 volt load between the center tap
of a primary and one load line is EXACTLY like an autotransformer.
There is no requirement that a neutral be connected to the panel
as long as the (plate) transformer can handle the unbalanced
primary current.
73,
... Joe, W4TV
On 6/2/2010 12:19 PM, Ron McCurdy wrote:
> Jim,
>
> I've been engineering electrical systems since 1962. You are wrong. He
> must ground the tap where he gets the "neutral" and provide some type of
> fuse or circuit breaker protection on the "hot". Otherwise, if he
> accidentally gets the hot grounded to something, there will be an arc until
> someone runs to shut off the power to the transformer...it won't trip til
> someone is fried.
>
> Wouldn't want that on my conscience!
>
> Ron, KE5QDA
>
> -----Original Message-----
> From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On
> Behalf Of Jim Brown
> Sent: Tuesday, June 01, 2010 1:36 PM
> To: AMPS List
> Subject: Re: [Amps] Bridging 120v loads across HV primary windings
>
> On Sun, 30 May 2010 14:34:35 -0400, Martin Flynn wrote:
>
>> Vic,
>> Run the 4 wire circuit and call it a day. I ran this very issue by a
>> licensed master electrician on Friday.
>
>> Direct quote: "If any portion of the load is 120 volt, you need a
>> neutral. If you are hell-bent on a 2 wire + ground supply, get a 208
>> volt fan and appropriately tapped transformer"
>
> Your licensed master electrican was WRONG. It is entirely legal, and
> entirely proper from an engineering point of view to place a 120V load
> across half of a center tapped transformer as long as that load is center
> tap is not grounded.
>
> 73,
>
> Jim Brown K9YC
>
>
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|