Racal Instruments 1260-112, User Manual, Page: 14 / 60

1260-112 User Manual
Specifications 1-4 EADS North America Defense
Test and Services, Inc. © 2002
About MTBF
The 1260-112 MTBF is >100,000 hours, calculated in accordance
with MIL-HDBK-217E, with the exception of the electromechanical
relays. Relays are excluded from this calculation because relay life
is strongly dependent upon operating conditions. Factors affecting
relay life expectancy are:
1. Switched voltage
2. Switched current
3. Switched power
4. Maximum switching capacity
5. Maximum rated carrying current
6. Load type (resistive, inductive, capacitive)
7. Switching repetition rate
8. Ambient temperature
The most important factor is the maximum switching capacity,
which is an interrelationship of maximum switching power,
maximum switching voltage and maximum switching current.
When a relay operates at a lower percentage of its maximum
switching capacity, its life expectancy is longer. The maximum
switching capacity specification is based on a resistive load, and
must be further de-rated for inductive and capacitive loads.
For more details about the above life expectancy factors, refer to
the data sheet for the switch plug-in module.
The relay used on the 1260-112 plug-in is EADS part no.
310256-001. The relay manufacturer’s specifications for this relay
are:
Life Expectancy:
Mechanical
100,000 operations
Electrical 100,000 operations at full rated load
(resistive)
For additional relay specifications, refer to the relay manufacturer’s
data sheet.