Installation manual

GEO Direct PWM Amplifiers – Preliminary Documentation
20 System Wiring
The AC connections from the fuse block to the GEO drive are made via a cable that is either purchased as
an option from Delta Tau (CONKIT1 or CONKIT1A) or the terminations to the connector may be made
as shown in Appendix A.
AC Input Connector Pin Out
Pin # Symbol Function Description Notes
1 L3 Input Depending on model 40VAC to 480VAC
2/3 L2 Input Depending on model Depending on type
4 L1 Input Depending on model
Wiring Earth-Ground
Panel wiring requires that a central earth-ground location be installed at one part of the panel. This
electrical ground connection allows for each device within the enclosure to have a separate wire brought
back to the central wire location. The ground connection is usually a copper plate directly bonded to the
back panel or an aluminum strip with multiple screw locations. The GEO drive is brought to the earth-
ground via a wire connected to the M4 stud on the top of the location through a heavy gauge, multi-strand
conductor to the central earth-ground location. The nut on the stud should be tightened to 5 inch-pounds.
Earth Grounding Paths
High-frequency noises from the PWM controlled power stage will find a path back to the drive. It is best
that the path for the high-frequency noises be controlled by careful installation practices. The major
failure in problematic installations is the failure to recognize that wire conductors have impedances at
high frequencies. What reads 0 ohms on a DVM may be hundreds of ohms at 30MHz. Consider the
following during installation planning:
1. Star point all ground connections. Each device wired to earth ground should have its own conductor
brought directly back to the central earth ground plate.
2. Use unpainted back panels. This allows a wide area of contact for all metallic surfaces reducing high
frequency impedances.
3. Conductors made up of many strands of fine conducts outperform solid or conductors with few
strands at high frequencies.
4. Motor cable shields should be bounded to the back panel using 360-degree clamps at the point they
enter or exit the panel.
5. Motor shields are best grounded at both ends of the cable. Again, connectors using 360-degree shield
clamps are superior to connector designs transporting the shield through a single pin. Always use
metal shells.
6. Running motor armature cables with any other cable in a tray or conduit should be avoided. These
cables can radiate high frequency noise and couple into other circuits.
Wiring 24V Logic Control
An external 24Vdc power supply is required to power the logic portion of the GEO drive. This power can
remain on, regardless of the main AC input power, allowing the signal electronics to be active while the
main motor power control is inactive. The 24V is wired into connector J4. The polarity of this connection
is extremely important. Carefully follow the instructions in the wiring diagram. This connection can be
made using 16 AWG wire directly from a protected power supply. In situations where the power supply is
shared with other devices, it may be desirable to insert a filter in this connection.
The power supply providing these 24 volts must be capable of providing an instantaneous current of at
least 1.5 amps to be able to start the DC-to-DC converter in the GEO drive. In the case where multiple
drives are driven from the same 24V supply, it is recommended that each drive be wired back to the
power supply terminals independently. It is also recommended that the power supply be sized to handle
the instantaneous inrush current required to start up the DC-to-DC converter in the GEO drive.