Efficient Networks Siemens Sinamics S120 - Manual (Page 193)

Basic functions
6.8 Armature short-circuit brake, internal voltage protection, DC brake
Drive Functions
Function Manual, (FH1), 07/2007 Edition, 6SL3097-2AB00-0BP4
193
This eliminates the necessity for using a VPM (Voltage Protection Module), for 1FE motors
e.g. VPM 120 or VPM 200.
When the Motor Module supports the internal voltage protection (r0192.10=1), the Motor
Module automatically decides on the basis of the DC link voltage whether the internal
armature short-circuit is applied. In this case, the voltage protection is also valid if the
DriveCliQ connection between the Control Unit and the Motor Module is interrupted.
A CSM (Control Supply Module) generates a 24 V supply from the DC link for the Motor
Module and other components of the drive group. To ensure a stable power supply, the DC
link voltage must be maintained within safe limits.
The DC link voltage is monitored in the Motor Module.
If the DC link voltage exceeds 800 V, the internal armature short-circuit is activated. This
prevents switch-off of the Motor Module due to internal hardware error detection.
If the DC link voltage drops below 450 V, the internal armature short-circuit is deactivated
again. This ensures that the necessary input voltage for the Control Supply Module is
maintained.
Note
With the internal voltage protection active, the motor must not be powered by an external
source for an extended period of time (e.g. by pulling loads or another coupled motor).
Prerequisites for the use of the internal voltage protection are:
● A Motor Module booksize is being used.
● The power unit current (r0289) must be at least 1.8 times the motor current (p0331).
● One of the following motor types was parameterized:
– Rotating permanent-magnet synchronous motor (p0300 = 2xx)
– Linear permanent-magnet synchronous motor (p0300 = 4xx)
Note
An activated internal voltage protection extends the speed range by raising the speed
limits (p1082, ..) also for EMF values > 800 V. The original settings are not buffered.
CAUTION
With the internal voltage protection is active (p1231 = 3), after the pulses have been
canceled, all of the motor terminals are at half of the DC link potential (without
internal voltage protection the motor terminals have a no voltage condition)!
DANGER
The voltage protection is not switched-out. Kinetic energy is converted into heat
(power loss) in the drive converter and motor. If the power loss is too high or if this
operation takes too long, then this can result in thermal overload of the drive.
Note
Deactivation of the voltage protection can always be initiated but will only become
effective after POWER ON.