Siemens 420 manual 126

3 Functions Issue 07/04

WARNING

For compound braking, regenerative braking is superimposed on the DC braking (braking along a ramp). This means that components of the kinetic energy of the motor and driven load are converted into thermal energy in the motor. If this power loss is too high or if the braking operation takes too long, then this can cause the drive to overheat !

When using compound braking it must be expected that there is a higher level of noise above the compound braking switch-in threshold.

NOTE

Compound braking is de-activated, if

-flying restart is active, and

-DC braking is active is selected.

The compound switch-in threshold VDC-Compis dependent on P1254

VDC-Comp(P1254 = 0) ≠ VDC-Comp(P1254 ≠ 0)

a)Auto-detect circuit enabled (P1254 = 1):

-VDC-Comp(P1254 = 1) is automatically calculated when the drive inverter runs-up - i.e. after the line supply voltage has been connected

-Using the auto-detect function, the VDC-Compthreshold automatically adapts itself to the line supply voltage at the particular installation location.

b)Auto-detect function disabled (P1254 = 0):

-VDC, Comp = 1.13 ⋅ 2 ⋅ P0210

-The VDC-Compthreshold is immediately re-calculated after entering P0210

-P0210 must be adapted to the particular installation location

MICROMASTER 420	Operating Instructions
126	6SE6400-5AA00-0BP0