SERVICE TIP

Grounding Your Drive

To ground your 1336 IMPACT drive, you need to:

1. Connect the drive to the system ground at the power ground (PE) terminal provided on the power terminal block (TB1).
2. Define the paths through which the high frequency ground currents flow.
3. Connect the ground conductor of the motor cable (drive end) directly to the drive ground terminal, not to the enclosure bus bar.
4. Ground the encoder connections (if you are using an encoder).
5. Ground the control and signal wiring.
6. Connect the TE terminal block (if used).
7. Connect the ground bus to adjacent building steel or a floor ground loop.
8. Solidly ground the RFI filter, if you need to use one.
9. These steps are explained in greater detail in the following sections.

Wire one PE terminal to the ground bar in the control panel.  The other PE terminal shall be wired directly to the motor - ungrounded except right at the motor.

Grounding the Discrete Control and Signal Wiring

To ground the control and signal wiring, you need to:

1. Ground the 0V or ground terminal at the equipment (source) end, not the drive end. You must ground all control and signal wiring at a single point in the system, remote from the drive.
2. Ground the shield if you are using shielded control and signal wires.

Connecting the TE Terminal Block
(found on larger frame sizes only)

The TE terminal block is used for all control signal shields within the drive. Refer to the frame specific chapters for the TE terminal block location.

The TE terminal block accepts wire with the following specifications:

Grounding the Safety Ground (PE)

Most codes require a safety ground. You can connect the ground bus to adjacent building steel (such as a girder or joist) or a floor ground loop, provided that the grounding points comply with your national (such as NEC), regional, or local regulations.

Connecting the Drive to the System Ground

Connect the drive to the system ground at the power ground (PE) terminal provided on the power terminal block (TB1). Ground impedance must conform to the requirements of national and local industrial safety regulations (such as NEC, VDE 0160, and BSI). You should inspect and test the ground impedance at appropriate and regular intervals.

Even if you have a floating secondary, the building must have a safety (earth) ground.

In any cabinet, you should use a single, low-impedance ground point or ground bus bar. You should:

• Ground all circuits independently and directly to this ground point or bus bar.
• Directly connect the AC supply ground conductor to this ground point or bus bar.

Defining the High Frequency Ground Current Paths

You need to define the paths through which the high frequency ground currents flow. Defining these paths helps to assure that noise-sensitive circuits do not share a path with high-frequency ground currents and to minimize the area enclosed by these paths. You must separate current carrying ground conductors. Control and signal ground conductors should not run near or parallel to a power ground conductor.

Connecting the Ground Conductor of the Motor Cable

Connect the ground conductor of the motor cable (drive end) directly to the drive ground terminal, not to the enclosure bus bar. Grounding directly to the drive (and filter, if installed) provides a direct route for high-frequency current returning from the motor frame and ground conductor. At the motor end, you should also connect the ground conductor to the motor case ground.

If you use shielded or armored cables, connect the shield to the drive chassis and the motor frame.

Posted 4 December 2000