Bypass Function - Siemens SINAMICS G150 Operating Instructions Manual

Functions, monitoring, and protective functions
9.3 Extended functions
9.3.2

Bypass function

The bypass function uses digital drive outputs to activate two contactors and uses digital
inputs to evaluate the contactor's feedback (e.g., via TM31). This circuit allows the motor to
be operated using the converter or directly on the supply line. The contactors are activated
by the converter. The feedback signals for the contactor positions have to be returned to the
converter.
The bypass circuit can be implemented in two ways:
● without synchronizing the motor to the line supply
● with synchronizing the motor to the supply.
The following applies to all bypass versions:
● The bypass switch is also always shut down if one of the "OFF2" or "OFF3" control word
signals is canceled (motor coasts down). The motor remains connected if OFF1 is
canceled.
● Exception:
If necessary, the bypass switch can be interlocked by a higher-level controller such that
the drive can be shut down completely (i.e. including the controller electronics) while the
motor is operated on the supply.
The protective interlocking must be implemented on the system side.
● When the converter is started up again after POWER OFF, the status of the bypass
contactors is evaluated. After powering up, the converter can thereby change straight into
"Ready to start and bypass" status. This is only possible if the bypass is activated via a
control signal, the control signal (p1266) is still present once the system has been
ramped up, and the "automatic restart" function is active (p1210 = 4).
The bypass function is automatically restarted by the restart process. To accelerate the
motor to the setpoint speed or to synchronize it to the network, the pulse enable may
takes place with the motor rotating. In this case, it is recommended that you activate the
"Flying restart" function (p1200 = 1) to prevent high current peaks.
● Changing the converter into "Ready to start and bypass" status after powering up, is of a
higher priority than switching back on automatically.
● Monitoring of the motor temperatures using temperature sensors is active while the
converter is in one of two statuses "Ready to start and bypass" or "Ready for operation
and bypass".
● The two motor contactors must be designed for switching under load.
Note
Information on the examples
The examples contained in the following descriptions are only basic circuits designed to
explain the basic function. The dimensions of specific circuit configurations (contactors,
protective equipment) must be calculated for specific systems.
552
Converter cabinet units
Operating Instructions, 07/2016, A5E03347396A