The Ground Conditions Of The Power Supply Network - REXROTH EcoDrive Cs Project Planning Manual

Rexroth EcoDrive Cs Drives
6.7

The Ground Conditions of the Power Supply Network

Grounded three-phase current
networks
Ungrounded three-phase
networks
Overvoltage
DOK-ECODR3-DKC**.3-CS*-PR02-EN-P
Drive controllers of the Rexroth EcoDrive Cs family can be operated on
three-phase current networks with grounded star point or external
conductors without potential isolation.
Ungrounded networks (IT networks) present the increased danger of
unallowable phase to ground overvoltages occurring. Drive controllers of
the Rexroth EcoDrive Cs family can be protected against overvoltages
• By connecting them via an isolating transformer (the star point of the
output side and the PE connection of the power supply unit are linked
on a shared ground rail)
- or -
• If the facility is protected via an overvoltage suppressor.
Note : Connecting Rexroth EcoDrive Cs drive controllers via an
isolating transformer offers the best protection against
overvoltage as well as the greatest operating safety.
The periodic overvoltage of Rexroth EcoDrive Cs drive controllers
between phase (L1, L2, L3) and ground may not exceed 1000 V
(threshold value).
Transient overvoltage (< 50 µs) may, as per EN61800-3/1996, equal a
max value of 1000 V phase to phase and 2000 V phase to ground.
Note: If higher overvoltages occur, then they must be limited with the
use of overvoltage suppressors in the cabinet or building.
Note: Mains voltages exceeding the specified range require the use
of a step-down transformer.
Mains and Supply Voltage Connection
6-17