Associated Equipment
Page
6-16
890CS Common Bus Supply - Frames B & D; 890CD Common Bus Drive and 890SD Standalone Drive - Frames B, C & D
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9
10
11
A
B
C
D
1
2
3
4
5
6
7
E
Circuit Breakers
We do not recommend the use of circuit breakers (e.g. RCD, ELCB, GFCI), but where their use is
mandatory, they should:
•
Operate correctly with dc and ac protective earth currents (i.e. type B RCDs as in Amendment 2 of
IEC755).
•
Have adjustable trip amplitude and time characteristics to prevent nuisance tripping on switch-on.
When the ac supply is switched on, a pulse of current flows to earth to charge the internal/external ac
supply EMC filter’s internal capacitors which are connected between phase and earth. This has been
minimised in Parker SSD Drives’ filters, but may still trip out any circuit breaker in the earth system. In
addition, high frequency and dc components of earth leakage currents will flow under normal operating
conditions. Under certain fault conditions larger dc protective earth currents may flow. The protective
function of some circuit breakers cannot be guaranteed under such operating conditions.
WARNING
Circuit breakers used with VSDs and other similar equipment are not suitable for personnel protection.
Use another means to provide personal safety. Refer to EN50178 (1997) / VDE0160 (1994) / EN60204-1
(1994)
