Eaton CMD(24VDC), Руководство пользователя

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2 Engineering
2.5 Mean time to dangerous failure MTTFD
CMD(24VDC), CMDTD 08/23 MN121001ZU-DE/EN Eaton.com
27
For channel 2 the DC
avg
for the CMD was calculated at DC
avg
= 90 %.
The undervoltage release can be estimated a DC
avg
= 60 % provided that
regular inspections are carried out.
The generally recognized inspection frequency is a hundred times more
often than the MTTF
D
. The test interval can be determined from:
2.5 Mean time to dangerous failure MTTF
D
The MTTF
D
time for the components is based on
with B
10D
: Lifespan up to a dangerous failure ( ￫ table 1 and ￫ table 2)
n
op
: Average number of annual switch operations
The MTTF
D
time for the CMD(24VDC) contactor monitoring device was
calculated at MTTF
D
= 125 years. This value is based on a maximum
operating frequency of 350, 400 operations/year (1 operation per minute,
16 hours per day, 365 days a year).
The MTTF
D
time of the contactors depends on the application.
The utilization category in accordance with IEC/EN 60947-4-1 and the
operating frequency are an important factor here. Depending on the
utilization category, the following values (
￫ table 1) can be applied to B
10D
.
￫
The function of the undervoltage release must be tested
manually at regular intervals.
T
Test
=
MTTF
D
(formula 1)
100
￫
It is recommended that the test is carried out under no-load
conditions.
MTTF
D
=
B
10D
(formula 2)
0.1 x n
op