Panasonic is part of a large worldwide groupselling relays and associated switching products under different brand names in different territories.The conditions of use in some territories may differ from those customary in Europe. In particular there are often major differences in regard to national and international specifications, such as UL, CSA, VDE, SEV, EVE, SEMKO, etc. Thus, when considering contact loads as stated in this catalogue (e.g. 10 A, 30 VDC for the SP relay) its hould be understood that these values are not necessarily an absolute maximum but tested ratings. Mostly the stated value has been tested for a certain life expectancy as stated by the manufacturer or the respective test house. Thus, under different conditions, the stated “maximum” may, in practice, be safely exceeded.
indicates the mean
tim period which system,
equipment, part operates normally
between two incidences repair. F
MTTF acronym mean tim to
failure.
4. F
MTBF acronym mean time
between failures.
Mean failure rate defined follows:
Mean failure rate Total failure count/
total operating hours
In general, failure rate refers to
momentary failure rate. For
example, none light bulbs has
failed for 100 hours, the degree of
reliability defined in, 100 hours tim is
10/10 100%. The reliability of
repairable products recognized as
“reliability broad sense the term ”.
3. This represents
the probability which system,
equipment, part, which has continued
normal operation certain point of
time, becomes faulty the subsequent
specified tim period.
For repairable products, their
serviceability aintainability another
problem.
1.
This means that product can continue
normal service infinitely. lia ility
Degree reliability represents
percentage ratio reliability. addition, reliability product
design becoming serious concern for
the manufacturing industry. In
the relay industry, reliability use has a
significance aspects servicing. indicates the mean tim period
until product becomes faulty MTTF
normally applies unrepairable products
such parts and materials.
Product reliability the user's site is
called “reliability use”, which consists
mainly reliability the broad sense.
The JIS Z8115 standard defines the
degree reliability follows:
The probability which system,
equipment, part provides the specified
functions over the intended duration
under the specified conditions.
Failure rate often represented the
unit percent/hours. lia ility lia ility
o e
Reliability “built” into products. short,
reliability has three senses: i.
Availability
3. esign reliability
H factor, redundancy,
fo l-proof, fail-safe
[2] RELIABILITY MEASURES
The following list contains some the
most popular reliability measures:
R eliability measure
Sample
representation
Degree reliability R(T) 99.
22 ds_x61_en_relay_technical_information_091112D
.
MTBF tells how long product can be
used without the need for repair.e.
2 lia ility e
T rm
Every product has finite service lifetime. lia bility (narrow sense), durability
Long life tim TTF, 10, R(T),
L failure rate: Lam (^), MTBF
2. This is
referred intrinsic reliability which
consists mainly reliability the narrow
sense. hen product
has broken down, the user may throw it
Reliability
(broad sense)
away repair it.9%
MTBF 100 hours
MTTF 100 hours
Failure rate fit, /hour
Safe life B10 hours
(b) MTTF
(c) Safe life
1.
Sometimes MTBF used represent
the service lifetime before failure. reliability
of the product itself, serviceability the
product, and reliability product design.
The relay one such objective of
MTTF. aintainability
M TTR
P reven tive aintenance, predicted
m aintenance
3. only three bulbs
remained alive, the degree reliability is
3/10 30%. For parts with low
failure rates, “failure unit (Fit) 10-9 /
hour” often used instead failure rate.
2.
Percent/count normally used for relays.Reliability
RELIABILITY
[1] WHAT RELIABILITY?
1. ilu te
Failure rate includes mean failure rate
and entary failure rate. lia ility e
T rm
In the industrial world, reliability an
index how long particular product
serves without failure. MTBF
only applies repairable products
