KEB COMBIVERT G6, Safety Manual

Page: 11 / 24

GB - 11
Safety Function STO
Jerks in error
case
In case of double malfunction it can lead to unwanted jerk, the
rotation angle is depending on the number of poles of the se-
lected drive and the gear ratio.
Calculation of the jerk:
Rotation angle of the jerk W
R
[°] =
180°
–––––––––––––––––––––––––––––––––
Pole-pair number p • gear reduction ratio g
The probability of the jerk is < 1.84 *10
-15
1/h.
This behaviour can occur by a short circuit of the IGBTs. The error should be regarded as
critical, if the drive remains in STO status.
2.2 Classification of STO according IEC 61508
PFH 8.1 *10^-11 1/h
PFD 7.1 * 10^-6 on demand
Proof-Test-Interval 20 years
For SIL classification in connection with the applications consider the failure rates of the ex -
ternal switch devices for final evaluation.
2.3 Classification of STO according EN ISO 13849
Control category 3
MTTF
D
>2500 years
DC medium
For the classification within a performance level in connection with the applications consider
the failure rates of the external switch devices for final evaluation.