*22291814_0715*Drive Technology \ Drive Automation \ System Integration \ Services

Data Sheet

Functional SafetyCharacteristic Safety Values for BE.. Brakes

Edition 07/2015 22291814/EN

SEW-EURODRIVE—Driving the world

Table of contents

Data Sheet – Characteristic Safety Values for BE.. Brakes 3

Table of contents1 Datenblatt ................................................................................................................................... 4

1.1 Notes .............................................................................................................................. 41.2 Safety characteristics ..................................................................................................... 41.3 Characteristic safety values ........................................................................................... 51.4 Sample calculations ....................................................................................................... 5

2229

1814

/EN

– 0

7/20

15

1 DatenblattNotes

Data Sheet – Characteristic Safety Values for BE.. Brakes4

1 Datenblatt

INFORMATIONPlease observe the data specified in this publication. This document does not replacethe detailed operating instructions "DR..71 – 315, DRN80 – 315 AC Motors".

Observe the following other applicable documentation:

• "DR..71 – 315, DRN80 – 315 AC Motors" operating instructions

• "DR.. Series AC Motors" catalog

• "DRN.. Series AC Motors" catalog

1.1 Notes

Definition of the value "MTTFd":MTTFd is a statistical value. It is defined in the standard EN ISO 13849-1 as "expectedvalue of the mean time to dangerous failure".Statistical value means that it is a value that has been determined empirically. The val-ue does not imply a "guaranteed service life" or a "failure-free time".For the BE.. brake, the value MTTFd refers to its capability of performing the mechani-cal switching operation, that is to move the pressure plate. Wear of the brake lining,which is caused by the conversion of kinetic energy during the braking process, doesnot affect this value.The values differ for every application because the value MTTFd depends on the meannumber of actuations per year.

INFORMATIONObserve the technical data for the brake in the "DR..71 – 315, DRN80 – 315 AC Mo-tors" operating instructions, in particular the maximum permitted work done by thebrake.

INFORMATIONUsage in safety-related applications:The system/machine manufacturer is responsible for compliance of the system/machine with applicable safety regulations.

1.2 Safety characteristics

Definition of the safety architecture (category):The safety architecture (category) classifies safety-related components regarding theirresistance to errors and their response in the event of an error based on the reliabilityand/or the structural arrangement of the parts. A higher resistance to errors means ahigher potential to reduce risk.

2229

1814

/EN

– 0

7/20

15

1DatenblattCharacteristic safety values

Data Sheet – Characteristic Safety Values for BE.. Brakes 5

1.2.1 BE.. brake

Characteristic Characteristic to EN ISO 13849-1

Classification Category B

1.3 Characteristic safety values1.3.1 BE.. brake

Definition of the characteristic safety value B10d:The value B10d specifies the number of switching cycles at which 10% of componentshave failed dangerously (definition according to standard EN ISO 13849-1). Faileddangerously means in this context that the brake does not realize at least one of thesafety functions when required. This means the brake does not deliver the necessarybraking torque.

Size B10d

Switching cycles

BE05 16 000 000

BE1 12 000 000

BE2 8 000 000

BE5 6 000 000

BE11 3 000 000

BE20 2 000 000

BE30 1 500 000

BE32 1 500 000

BE60 1 000 000

BE62 1 000 000

BE120 250 000

BE122 250 000

1.4 Sample calculationsBelow some examples of how to use the value B10d to calculate the mean time to dan-gerous failure (MTTFd).In the examples, the values MTTFd are calculated for size BE11 based on 2 differentswitching frequencies. The equations used are described in standard EN ISO13849-1.The following sample calculations are based on two selected applications. Adjust thecalculation for other applications. Also, other parameters might influence the calcula-tion. If you have any questions on calculating the values, please contactSEW‑EURODRIVE.

2229

1814

/EN

– 0

7/20

15

1 DatenblattSample calculations

Data Sheet – Characteristic Safety Values for BE.. Brakes6

1.4.1 Example 1Input data for the BE11 brake:

• B10d = 3 000 000

• Operating days per year: dop = 300 d/a

• Operating period per day: hop = 24 h/d• Cycle time: tcycle = 87 s• Starting frequency: 41.4 1/h

MTTFB

nd

d

op

=

×

10

0 1.

nd h

s

ht

op

op op

cycle

=

× × 3600

n

d

a

h

d

s

hs a

op =

× ×

=

300 24 3 600

87297 931

1

MTTF a ad =

×

=3 000 000

0 1 297 931100 7

,,

MTTFd = 100 yearsThe result is assigned to "High" according to standard EN ISO 13849-1 as shown inthe following table.

Designation Range

Low 3 years ≤ MTTFd < 10 years

Medium 10 years ≤ MTTFd < 30 years

High 30 years ≤ MTTFd ≤ 100 years

1.4.2 Example 2Input data for the BE11 brake:

• Same values as in example 1 but with reduced cycle time• Cycle time: tcycle = 25 s• Starting frequency: 144 1/hPerform the calculation as shown in example 1.

MTTFd = 29 yearsThe result is assigned to "Medium" according to standard EN ISO 13849-1.

Input data:

Calculation:

Inserting the val-ues:

Result:

Input data:

Calculation:

Result:

2229

1814

/EN

– 0

7/20

15

SEW-EURODRIVE—Driving the world

SEW-EURODRIVE GmbH & Co KGP.O. Box 302376642 BRUCHSALGERMANYPhone +49 7251 75-0Fax +49 7251 75-1970sew@sew-eurodrive.com

www.sew-eurodrive.com