Rockwell Automation 2090 Ultra3000 Installation Manual - Manual (Page 32)

Publication 2098-IN003E-EN-P — April 2004
1-8 Installing Your Ultra3000
Sizing an Enclosure
As an additional aid in sizing an enclosure, with no active method of
heat dissipation, either of the following approximate equations can be
used:
Transformer Sizing
The Ultra3000 does not require isolation transformers. However, a
transformer may be required to match the voltage requirements of the
controller to the available service. To size a transformer for the main
AC power inputs, the power output (KVA) of each axis must be
known. This can be derived by calculating the horsepower for each
axis and converting that horsepower into units of watts. If you are
supplying power to more than one motor and an Ultra3000, simply
add the kW ratings together from each calculation to get a system kW
total.
Definitions:
kW = power or real power
KVA = apparent power
Transformer KVA rating = (Sum of average output power of each axis)
x 2.0.
Metric Standard English
Where T is temperature difference between
inside air and outside ambient (°C), Q is heat
generated in enclosure (Watts), and A is
enclosure surface area (m
2 ). The exterior surface
of all six sides of an enclosure is calculated as
Where T is temperature difference between
inside air and outside ambient (°F), Q is heat
generated in enclosure (Watts), and A is
enclosure surface area (ft²). The exterior surface
of all six sides of an enclosure is calculated as
A = 2dw + 2dh + 2wh A = (2dw + 2dh + 2wh) / 144
Where d (depth), w (width), and h (height) are in
meters. Where d (depth), w (width), and h (height) are in
inches.
IMPORTANT
If using an autotransformer, ensure that the phase to
neutral/ground voltages do not exceed the input
voltage ratings of the drive.
A
0.38Q
1.8T 1.1 –
------------------------ = A
4.08Q
T 1.1 –
---------------- =