Converter Operation; Supply Line Configuration; Reducing Bearing Currents - Siemens 1LA8 Operating Instructions Manual

4.13

Converter operation

The following chapter is relevant only to machines of series 1PQ8 or if the machine was ordered
for operation on the rectifier.
Note
The order number shows whether the machine was ordered for operation with converter: the
9th digit of the order number features the letter "P" or "Q".
4.13.1

Supply line configuration

NOTICE
Asymmetric voltage load during operation on a TN system in delta connection
An asymmetric voltage load of the machine winding can occur during operation on a TN
system in delta connection with a grounded line conductor. Winding damage can result.
● Do not operate the machine on a TN system with a grounded line conductor.
NOTICE
Ground fault during operation on an IT system
If a ground fault occurs when connected to an IT supply system, the insulation is excessively
stressed. Winding damage can result.
● If possible, complete the process within two hours.
● Rectify the fault cause.
● Deploy a ground fault monitoring.
4.13.2

Reducing bearing currents

Taking the following actions will reduce the bearing currents:
● Ensure that the contacts are established over a large area. Solid copper cables are not
Equipotential bonding conductors:
Use equipotential bonding conductors:
● Between motor and driven machine
● Between motor and converter
● Between the terminal box and the RF grounding point at the motor enclosure.
SIMOTICS TN Series N-compact 1LA8
Operating Instructions 05/2016
suitable for high frequency grounding because of the skin effect.
Preparations for use
4.13 Converter operation
37