Parameters
116 M-Max Series Adjustable Frequency Drive MN04020003E—October 2013 www.eaton.com
Braking, continued
PNU ID
Access
RUN Value/Range Description
Factory Setting
(P1.3)
P12.5 504 X — Brake chopper 0
0 Brake-chopper deactivated
1 Automatic activation in operation (RUN)
2 Automatic activation in operation (RUN) and upon stop (STOP)
P12.6 1447 X — Brake chopper, DC bus switching threshold 765
0–870V This function is only active with the three-phase frequency
inverters MMX34…3D3_ (3.3A) to MMX34…014_ (14A)
The switching threshold for the brake transistor should always
be above the maximum DC link voltage
For example, allowing for the maximum permissible input
voltage peak of 10%:
U
LN
= 400 Vac
U
LN
+10% = 400 Vac = 440 Vac
U
DC
= 1.35 x U
LNmax
= 1.35 x 440V = 594 Vdc (maximum
permissible DC link voltage in motor operation)
Allowing for an energy absorption from the DC link of around
30% during braking, the on threshold here for the braking
transistor should be set to around 780V
Note: Lower values for the on threshold will switch on the
braking resistor earlier so that it is subject to a greater load
The DC link voltage is shown at M1.8. In practice, the value of
the DC link voltage is around 565V at U
LN
= 400V
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