Section 2: Dv/Dt Filter; Figure 55. Typical Dv/Dt Filter - Eaton SC9000 EP Installation Manual

Appendix D: Optional equipment

Section 2: dV/dt filter

The SC9000 EP dV/dt filter is a combination of reactors,
capacitors and resistors that reduces the sharp change in
voltages due to IGBT switching. Smoothing the voltage
spikes reduces the high frequency ringing, lowers the
voltage added to the drive output and reduces the effects
on motor insulation and bearings when cable lengths
are excessive.
The dV/dt filter reduces high frequency ringing on the SC9000
EP output. It does not reduce drive output Total Harmonic
Distortion. The SC9000 EP Sine Filter serves that purpose.
When to use a dV/dt filter
For motors used with SC9000 EP drives, the decision to
apply a dV/dt filter depends upon the motor used and the
connecting cable lengths between the SC9000 EP and
the motor.
Longer cable runs are possible with a dV/dt filter present.
Permissible lengths depend upon the type of motor used.
dV/dt use on a standard motor
If a standard (non-inverter rated) motor is used,
Apply a dV/dt filter to a 2400 V motor whenever the
●
connecting cable lengths are greater than 60 feet
Apply a dV/dt filter to a 4160 V motor whenever the
●
connecting cable lengths are greater than 120 feet
Apply only a sine filter (see Chapter 3) whenever the cable
●
length is greater than 1250 feet
62 SC9000 EP medium voltage drives IB020001EN—February 2016 www.eaton.com
dV/dt use on an inverter duty motor
Apply a dV/dt filter to a 2400 V motor whenever the
●
connecting cable lengths are greater than 150 feet
Apply a dV/dt filter to a 4160 V motor whenever the
●
connecting cable lengths are greater than 300 feet
Apply only a sine filter (see Chapter 3) whenever the cable
●
length is greater than 1250 feet
Contact Eaton if the motor cable length is greater than what
is recommended above and the optional output filter has not
been supplied.
Figure 55 shows a representative dV/dt elementary diagram.

Figure 55. Typical dV/dt filter