The Centurion is a 3 wire connection; 2 hot and the third is connected
directly to the chassis and must be ground, not neutral. The Centurion does
not use phase to ground to develop 120 v for the fan, rather they use
windings on the transformer. This is the information contained in my
Centurion manual, and which I confirmed with their service department
serveral months ago.
If they did use phase to ground, you could end up with the chassis floating
at 240v if the ground connection were intermittent. The operator could
easily become the pull down resistor.
----- Original Message -----
From: "Michael Tope" <W4EF@dellroy.com>
To: "Jason Buchanan" <jsb@digistar.com>; <amps@contesting.com>
Sent: Thursday, December 04, 2003 1:50 AM
Subject: Re: [Amps] 220V service for amplifier
> Jason,
>
> I ran into this problem with the Henry 2K-D that was donated
> to our local club station. Even when operated from a 240VAC
> circuit, the Henry still requires 120VAC from the mains
> to run the blower and the filament transformer. The Henry
> picks this voltage up between one phase of the 240 VAC
> circuit and the system "neutral". A fourth connection is made
> between the amplifier chassis and the electrical system safety
> ground (e.g. the "green wire"). As was mentioned in another
> posting, this "green wire" connection exists soley for purposes
> of electrical safety and normally doesn't carry any current. A
> proper 240 V connection to the Henry requires a 4 wire 240
> VAC circuit. Two hots, a neutral, and safety ground. A 3 wire
> 240 Volt connection won't work because it doesn't include a
> neutral connection. In this case, you can tie the neutral and the
> safety ground together at the amplifier and "share" the third
> green safety ground wire in the 3 prong mains plug. This will
> work as long as you don't have any ground fault interrupters on
> that circuit, but it is NOT COMPLIANT with NEC. In this
> configuration, if you have a fault in your current carrying
> neutral/safety ground connection, your chassis will be sitting
> at 110 VAC above ground potential ("ouch").
>
> On the other hand, if the Centurion power plug only requires
> three wires, then most likely, it doesn't require a neutral
> connection to get 120 VAC and 240 VAC from the mains
> at the same time. Our clubs Alpha 78s and my Drake L-7s are
> all configured this way. They don't require 120 VAC and
> 240 VAC from the mains simultaneously as does the
> Henry 2K-D (they get the 120 VAC from the center-tap
> of the HV transformer primary). If this is the case, then you
> can safely use a three wire 240 VAC source. One of the
> wires from the Centurion power cable will be tied to the
> chassis. This wire should be connected to the safety ground
> pin on the three-wire 240 VAC mains plug. Each one of the
> remaining two wires would then go to the one of the two
> remaining "hot" phase connections on the three wire 240
> VAC mains plug. In this case, there is no connection to the
> AC mains neutral. If you tie an amplifier like this (e.g. one
> with a 3 wire 240 VAC power connection) to a 4 wire mains
> circuit, then all you have to do is leave the connection to the
> mains plug neutral open.
>
> 73 de Mike, W4EF.....................................................
>
>
> ----- Original Message -----
> From: "Jason Buchanan" <jsb@digistar.com>
> To: <amps@contesting.com>
> Sent: Monday, December 01, 2003 7:19 PM
> Subject: [Amps] 220V service for amplifier
>
>
> >
> > I did some searching through the list but haven't managed to hit the
> > nail right on the head yet...
> >
> > For wiring a Ten-Tec Centurion amp to 220V, are there any recommended
> > plugs and outlets to use?
> >
> > I am thinking about using a 3 or 4 prong clothes dryer outlet and plug
> > combination for quick/easy disconnect, however the thing i'm wondering
> > about is where the neutral and ground tie together, since i'm fairly
> > sure that the Centurion doesn't have a 4 wire power cable running out of
> > it. Maybe i'm wrong (probably am wrong).
> >
> >
> > Any help and advice how to properly wire the amp would be greatly
> > appreciated.
> >
> >
> >
> > thanks,
> > Jason
> >
> > _______________________________________________
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> > Amps@contesting.com
> > http://lists.contesting.com/mailman/listinfo/amps
> >
>
>
>
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