Fig. 7-12: Safety Transformer According To En 60742; Fig. 7-13: Illustration Of The Limit Values For The 24 Vdc Voltage - Bosch Rexroth VSB 40.1 Project Planning Manual

7-10
PC Box
Danger without protective separation!
⇒ The 24 VDC input voltage must comply with the
requirements of the "Protective separation".
Plug and unplug the connector only in no-voltage
⇒
DANGER
condition!
400V + 5%
400V
400V - 5%
Fig. 7-12: Safety transformer according to EN 60742
Interfering AC voltage components such as resulting from an uncontrolled
3-phase current bridge connection without smoothing with a ripple factor
(see DIN 40110/10.75, section 1.2) of 5 % are permissible.
It follows from the above that as upper voltage limit the greatest absolute
value is 30.2 V and as lower voltage limit the lowest absolute value is
18.5 V.
1.05 x 28.8 V = 30.2 V
Upper limit 28.8 V
0.866 x 30.2 V = 26.1 V
1.5 x 20.4 V = 21.4 V
Lower limit 20.4 V
0.866 x 21.4 V = 18.5 V
Fig. 7-13: Illustration of the limit values for the 24 VDC voltage
L1 L3
L2
0V
30 el
cos (30 ) = 0.866
0
DOK-SUPPL*-VSB*40.1***-PR01-EN-P
VSB 40.1
PE
+ 24V
Sichertrafo.cdr
t
Wechsel.cdr