Magnetek Elevator Quattro DC - Advanced Output Filter; Grounding Considerations

Quattro DC Startup Guide
21
Advanced output filter
In our continued efforts to ensure a successful
modernization project from initial installation
through productive life, we have concentrated
our most recent efforts on developing a new
series of output filters. The objective of this
new technology is to further reduce the
potential risk of motor field or armature winding
failures over time. We chose the targeted goal
of achieving ≤ 500V/µsec change in voltage
with respect to time (a.k.a. dv/dt) as noted in
the 2010 Edition of NEMA MG1 Part 30. This
filter is available factory integrated into the
Quattro at the time of assembly or can be
added to drives in the field. Details on the
available kits for field retrofit are in the spare
parts section.
Grounding considerations
1. Encoder
a. Encoder isolation
2. The encoder must be electrically
isolated from the motor frame and the
motor shaft
a. Encoder cable
3. The cable type should be a PVC
braided shielded type with three 22ga
twisted pairs. A and A/, B and B/,
common and V should be the signals
paired together
4. The encoder shield is not to be
connected at the encoder end. On the
drive side of the cable a portion of
PVC material 1inch [25mm] should be
removed approximately 12inches
[300mm] from the connection to TB36
to expose the shield material.
5. Motor frame
a. The motor frame is required to
be grounded. The bond wire
should be returned to the
common ground point located
in the Quattro enclosure (PE).
6. Three phase power
a. The three phase wires must
be run with a ground
wire. This ground wire, which
is connected back to the utility
ground, is required to be
connected to the Quattro
ground (PE).
7. Control power, 230Vac
a. The neutral side of the control
power is required to be
grounded at the Quattro
ground (PE).
8. Ground the motor shaft
a. To eliminate the current
flowing through bearings, it is
recommended that the shaft of
the motor be grounded. This
can be done with the use of
shaft ground brushes. See the
spare parts list for available
brush kits.