Fig. 7-13: Safety Transformer According To En 60742; Fig. 7-14: Illustration Of The Limit Values For The 24 Vdc Voltage - Bosch Rexroth IndraControl VPP 21.1 Series Project Planning Manual

7-10
VPP 21 Box
400V + 5%
400V
400V - 5%
Fig. 7-13: 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
1,05 x 20,4 V = 21,4 V
Lower limit
20,4 V
0,866 x 21,4 V = 18,5 V

Fig. 7-14: Illustration of the limit values for the 24 VDC voltage

L1 L3
L2
0V
30 el
cos (30 ) = 0.866
0
DOK-SUPPL*-VPP*21.1***-PR02-EN-P
VPP 21.1
PE
+ 24V
sichertrafo.cdr9
t
wechsel.cdr9