Hi Mike -
ABS has no "inherent" knowledge that there is such a thing as 277/480 or
120/208 or 120/240 or whatever. It knows that there is a value that the user
enters for the voltage, and setting of either 1, 2, or 3 for # of poles. The
application will not allow you to connect a 277V connector to a 480V circuit
(unless you set up the voltage defs to allow for a range of connections like
that, which I wouldn't recommend).
I assume, when you say that "the total amps were added as single phase
amps", you are talking about in the "calculation block" to the right of the
main panel schedule block. If so, you are completely correct, this is a
calculation of single phase amps, not three phase amps. It is simply the
total of all of the values above it. The calculation of three phase amps for
the panel requires that the panel be balanced if you want a single number
that is the three phase amps.
Example:
I have a 480/277V panel and I put 3K on circuit 1, 2K on circuit 7, and 4K
on circuit 13. None of the other circuits have any load. A simple calc says
that the total 3 phase amps for the panel is 3000+2000+4000/(480*1.73) =
10.8A. In reality phase A is pulling 32.5A and phases B and C are 0.
There are 4 things that are important when trying to connect connectors to
circuits.
1 System Type: Either the system types must match or one of the system
types must be general. If this isn't true, they cannot be connected. Every
connector and circuit MUST have a system type.
2 System: To have the most versatile connections, leave system on both
the connector and circuit set to . That means that the connection
rule for systems is not enabled. If both the connector and circuit have a
system specified, the systems must be the same, or in the same system group
to allow connection.
3 # of Poles: This only applies to connectors and circuits with the
system type of Power & Lighting. A circuit must always have a # of Poles
setting. A connector can have a # of poles setting or can be set to
. If the # of poles are set to anything other than
the # of poles on the connector and circuit must match. If the # of Poles
setting is set to then the # of Poles setting on the circuit is
"inherited" by the connector.
4 Voltage: This only applies to connectors and circuits with the system
type of Power & Lighting. A circuit must always have a voltage. The
connector can have a voltage, defined in the voltage definitions, or any
number (you can type any number you want in the voltage combo box). You can
also have the value of in the voltage combo. If the voltage is
set to then the connector "inherits" the voltage from the
circuit. If the voltage is anything else, the voltage definitions are
checked to see if the voltage on the connector can are within the tolerance
for that particular voltage definition, and if they are within the range
connection is allowed.
Realistically we probably shouldn't include voltages in the system
definitions at all any more. Before the circuit objects existed, the system
definitions were used to control connectivity between different voltages.
For example, you didn't want to connect a 120V lighting fixture to a 277V
wiring run, so system definitions were used to "control" this connection.
Now that there are voltage rules, we could probably do away with the voltage
based system definitions completely.
hth
jason martin
Autodesk
"Mike Abernethy" wrote in message
news:E9DDF4AD694A0D75E7F72CAEDBA91716@in.WebX.maYIadrTaRb...
> When I set up my electrical drawing, I used Aecb Electrical
> Model(Imperial-ctb)4.dwt as the template, I selected 277volt lighting, 277
> volt power, 480volt power, 120volt lighting, 120volt power, 208volt
lighting
> and 208volt power as my electrical systems.
> I inserted light fixtures with a 277 volt systems definition. Then I
> inserted a panel with 277volt lighting as the system definition and the
> voltage as 277/480 volts 3 phase 4wire. Upon circuting groups of fixtures
to
> the new panel, I found the circuit shedule showed the circuits and loads
> correctly. However, the total amps were added as single phase amps and not
> distributed across all three pases as they should be for a 277/480 volt 3
> phase 4wire system.
>
> I deleted all of the circuiting, deleted the panel, purged the drawing. I
> then inserted a 480 volt three pahse 4 wire panel and tried to recircuit
the
> fixtures to the new panel.
> The fixtures would not allow me to select the new panel even though it
> showed as a possible selection in the properties. It constantly defaulted
to
> (Unassigned).
>
> The tutorials are no help in that they deal with modifying and
manipulating
> drawings with established setting and systems.
> How does the software handle a 277 volt system? Does it apply the loads as
> single phase or three phase?
>
> Is there any literature that step-by-step instructs you in the setup of an
> electrical drawing and selection of systems?
>
> What could I be doing wrong in the selection of the electrical systems?
>
> Why are the systems not established as 120/240 volt single phase three
wire,
> 120/240 volt three phase 4 wire, 120/208 volt three phase 4 wire, 277/480
> volt three phase 4 wire and 480 volt three phase three wire like the
> industry standard systems rather than as 120 volt lighting, 277 volt
> lighting, etc...?
>
> Mike Abernethy
> ZMM, Inc. Electrical Engr.
>
>
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