4-6
VLT is a registered Danfoss trademark
EMI Propagation
Drive generated EMI is both conducted to the AC line and
radiated to nearby conductors. See Figures 4-2 and 4-3
for illustrations.
VLT
AC Line
Motor cable
Ground
Potential 1
Potential 2
Potential 3
VFD
Motor
Stray capacitance
Stray capacitance
Figure 4-2. Ground Currents
Stray capacitance between the motor conductors, equipment ground,
and other nearby conductors results in induced high frequency currents.
High ground circuit impedance at high frequencies results
in an instantaneous voltage at points reputed to be at
“ground potential.” This voltage can appear throughout a
system as a common mode signal that can interfere with
control signals.
Theoretically, these currents will return to the drive’s DC
bus via the ground circuit and a High Frequency (HF) bypass
network within the drive itself. However, imperfections in
the drive grounding or the equipment ground system can
cause some of the currents to travel out to the power
network.
VLT
AC Line
Motor cable
VFD
Motor
Stray capacitance
Signal wiring
to BMS
Figure 4-3. Signal Conductor Currents
Unprotected or poorly routed signal conductors located close to or in
parallel to motor and AC line conductors are susceptible to EMI
.
Содержание VLT series
Страница 1: ...MOTION CONTROLS Service Manual VLT 4152 4652 VLT 5122 5602 VLT 6152 6652 VLT 8152 8652...
Страница 8: ......
Страница 20: ......
Страница 32: ......
Страница 41: ...2 9 VLT is a registered Danfoss trademark Figure 2 7 Inverter Section...
Страница 58: ......
Страница 96: ......
Страница 152: ......