1260-21 User Manual
Installation Instructions 2-8
Racal Instruments
©
2005
More About
Maximum Current
Ratings
The front panel connector and pins are rated for 10 A per pin,
with all channels conducting full-rated current. The relays are
rated at 10 A. This keeps the temperature rise within 10
°
C. It
should be noted that with all electromechanical relays, the higher
the switched power (voltage times current), the shorter the useful
life of the relays.
Definitions:
•
Max current carrying capacity
The maximum current that the relay can conduct if the relay is
not switched while voltage is applied. The maximum current
carrying capacity is affected by the size of the conducting
section of the contact at its smallest area. The listed values are
obtained from several tests in laboratories under room-
temperature conditions (21
°
C). The contact is considered to be
in free air. The maximum current carrying for the 1260-21 is
10 A.
•
Max
o
perating current
The current the contacts can switch while conducting, without
deteriorating. This depends on working conditions, such as
dissipated heat, cooling provisions, ambient temperature,
insulation material, etc. The maximum operating current for the
1260-21 is 10 A.
•
Recommended continuous current
The maximum current recommended for indefinitely-long time
periods. The primary concern here is the heat generated in the
relay. This specification can be applied for normal working
conditions. The specification includes a safety margin. However,
there are restrictions in the application of the given values. The
most important restriction is the cross-sectional area of the
connecting wire, insulation temperature range, and wire bundling.
The recommended continuous current for the 1260-21 is 10 A.
Installation
To install the 1260-21 Switching Module into a VXI mainframe
chassis, engage the printed circuit board into the grooves of the
desired chassis slot. Slide the 1260-21 into the chassis until its
connector mates with the connector on the chassis backplane.
Push firmly to fully seat the connector. Tighten the two retaining
screws at the top and bottom of the 1260-21 module.
