Delta Tau Geo MACRO, Руководство пользователя и справочное руководство

Страница: 43 / 205

Geo MACRO Drive User and Reference Manual
Connections 31
Input Power Filtering
Caution:
To avoid electric shock, do not touch filters for at least 10 seconds after removing
the power supply.
The Geo Drive electronic system components require EMI filtering in the input power leads to meet the
conducted emission requirements for the industrial environment. This filtering blocks conducted-type
emissions from exiting onto the power lines and provides a barrier for power line EMI.
Adequately size the system. The type of filter must be based on the voltage and current rating of the
system and whether the incoming line is single or three-phase. One input line filter may be used for
multi-axis control applications. These filters should be mounted as close to the incoming power as
possible so noise is not capacitively coupled into other signal leads and cables. Implement the EMI filter
according to the following guidelines:
•
Mount the filter as close as possible to the incoming cabinet power.
•
When mounting the filter to the panel, remove any paint or material covering. Use an unpainted
metallic back panel.
•
Filters are provided with a ground connection. All ground connections should be tied to ground.
•
Filters can produce high leakage currents; they must be grounded before connecting the supply.
•
Do not touch filters for a period of ten seconds after removing the power supply.
Motor Line Filtering
Motor filtering may not be necessary for CE compliance of Geo Drives. However, this additional
filtering increases the reliability of the system. Poor non-metallic enclosure surfaces and lengthy,
unbonded (or unshielded) motor cables that couple noise line-to-line (differential) are some of the factors
that may lead to the necessity of motor lead filtering.
Motor lead noise is either common-mode or differential. The common-mode conducted currents occur
between each motor lead and ground (line-to-neutral). Differential radiated currents exist from one motor
lead to another (line-to-line). The filtering of the lines feeding the motor provides additional attenuation
of noise currents that may enter surrounding cables and equipment I/O ports in close proximity.
Differential mode currents commonly occur with lengthy motor cables. As the cable length increases, so
does its capacitance and ability to couple noise from line-to-line. While every final system is different
and every application of the product causes a slightly different emission profile, it may become necessary
to use differential mode chokes to provide additional noise attenuation to minimize the radiated
emissions. The use of a ferrite core placed at the Geo Drive end on each motor lead attenuates differential
mode noise and lowers frequency (30 to 60 MHz) broadband emissions to within specifications. Delta
Tau recommends a Fair-Rite P/N 263665702 (or equivalent) ferrite core.
Common mode currents occur from noise spikes created by the PWM switching frequency of the Geo
Drive. The use of a ferrite or iron-powder core toroid places common mode impedance in the line
between the motor and the Geo Drive. The use of a common mode choke on the motor leads may
increase signal integrity of encoder outputs and associated I/O signals.
I/O Filtering
I/O filtering may be desired, depending on system installation, application, and integration with other
equipment. It may be necessary to place ferrite cores on I/O lines to avoid unwanted signals entering and
disturbing the Geo.