Efficient Networks Siemens Sinamics S120 - Manual (Page 160)

Vector control
4.20 Bypass
Drive Functions
160
Function Manual, (FH1), 07/2007 Edition, 6SL3097-2AB00-0BP4
● Synchronizing the motor to the line supply.
For all bypass versions, the following applies:
● The bypass is always switched-out when one of the control word signals "OFF2" or
"OFF3" is withdrawn.
● Exception:
When required, the bypass switch can be interlocked by a higher-level control so that the
drive converter can be completely powered-down (i.e. including the control electronics)
while the motor is operated from the line supply. The contactor interlocking should be
implemented on the plant/system side.
● When the drive converter restarts after POWER OFF, the state 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 (p1200 = 4) is active.
● 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 to operate and
bypass".
● The two motor contactors must be designed for switching under load.
Note
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.
Prerequisite
The bypass function is only possible for sensorless closed-loop speed control (p1300 = 20)
or V/f control (p1300 = 0...19) and when an induction motor is used.
Commissioning the bypass function
The bypass function is part of the function module "technology controller" that can be
activated when using the commissioning Wizard. Parameter r0108.16 indicates whether it
has been activated.
4.20.1 Bypass with synchronization with overlap (p1260 = 1)
Description
When "bypass with synchronization with overlap (p1260 = 1)" is activated, then motor is
transferred, synchronized to the line supply and is also retrieved again. During the
changeover, the two contactors K1 and K2 are simultaneously closed for a time (phase lock
synchronization).