Chapter 2
Installation and Configuration
©
National Instruments Corporation
2-7
NI PS-16 Power Supply User Manual
Before operating the NI PS-16 in this configuration, consider the following:
•
A phase-to-phase connection is allowed as long as the supplying
voltage is below 240 V +10%.
•
Use a fuse or a circuit breaker to protect the N (Neutral) input. The
N input is not protected internally and in two-phase configuration
would be connected to a hot wire.
Appropriate fuses and circuit breakers are specified in the
External Input
Protection
section.
External Input Protection
The NI PS-16 power supply is tested and approved for branch circuits up
to 20 A. External protection is only required if the supplying branch has an
ampacity greater than 20 A. In some countries local regulations might
apply, so check local codes and local requirements.
If an external fuse is utilized, a minimum value is required to avoid
undesired tripping of the fuse, shown in Table 2-2.
Operation in a Sealed Enclosure
When the power supply is installed in a tightly sealed enclosure, the
temperature inside the enclosure will be higher than outside. The inside
temperature defines the ambient temperature for the power supply.
The following is the result of such an installation, where the NI PS-16
power supply was placed in the middle of a sealed enclosure, and no other
heat producer was present:
Enclosure:
Rittal Type IP66 Box PK 9519 100,
plastic, 180 mm × 180 mm × 165 mm
Load:
24 V, 8 A; (= 80%) load is placed outside
the box
Input:
230 V
AC
Table 2-2.
Maximum and Minimum Ampacities for External Fuses
Ampacity
B-Characteristic
C-Characteristic
Minimum
10 A
6 A
Maximum
20 A
20 A
