Download Siemens TPS3 15 Specifications

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Power Supply Systems
Panelboards receive power from a variety of sources. For
example, a downstream panelboard typically receives power
from an upstream panelboard or switchboard. However,
power for the distribution system originates from a utility
power company. Power from the power company is stepped
down through a transformer for distribution to a residential,
commercial, or industrial facility.
There are a number of ways that the transformer secondary
windings providing service may be configured. In order to
properly select a panelboard, you need to understand which
voltage and system will be connected. The following examples
show a few of the more common systems, but other systems
and voltages are also common.
1Ø3W Power System
The following diagram illustrates a common single-phase, threewire (1Ø3W) distribution system. As this diagram shows, the
voltage between the neutral connection (N) of the transformer
secondary and either side of the secondary is 120 V and the
voltage across the entire secondary winding is 240 V.
Transformer
Secondary
A
120 Volts
Neutral
Primary
240 Volts
120 Volts
B
Ground
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