Delta CT2000 Series User Manual page 619

Chapter 19 EMC Standard Installation GuideCT2000 Series
3. Common-mode noise is coupled via the power cable to other power systems then the cable of such a power
system is coupled to the transmission system, as shown in Figure 3.
4. The common-mode noise of an unshielded power cable is transmitted to the ground via the stray capacitance.
Since both shielded wire and unshielded wire are connected to a common ground, other systems can be
interfered with by the common-mode noise that is transmitted from the ground back to the system via the shield.
See Figure 4.
5. When excessive pulse modulated currents pass through an un-grounded AC drive cable, it acts as an antenna
and creates radiated interference.
Unshielded cable
Noise
Cstray
Power
Cable
supply
Unshielded cable
Noise
Send
Noise
Send
19-6
System
Ground
Cstray
Receive
Ground
Unshielded cable
Cstray
Cstray
Ground
Load
Receive
Load