Lenze 9400 Manual - Manual (Page 330)

DC-bus operation
Basic dimensioning
Motor efficiency
8

330 EDS94SPP101 EN 7.1
8.5.3 Motor efficiency
For determining the power requirements, you have to consider the shaft power P
shaft
and
the motor efficiency. The motor efficiency can be found under the motor data.
8.5.4 Power loss of devices
When determining the power requirements, the power loss of the devices must be
considered ( Tab. 8-5).
8.5.5 Determining the power requirements
For determining the power requirements of the drive system you need to know the rated
power of the motors and their efficiency as well as the power losses of the controllers. The
power requirements are calculated with the following formula:
P
DCtotal
=
 n
i=1
⎨⎧⎩

P
shaft

i
η
i
+ (P
loss
)
i
⎬⎫⎭
P
DCtotal
Total power required by the drive system
P
shaft
Rated power of a connected motor
P
loss
Power loss of a controller
η Motor efficiency
I Index variable for device identification
n Number of devices in the drive system
The supply unit must be able to supply the calculated power requirements.
For application examples, please see 8.7 .
8.5.6 Determining the regenerative power requirements
Power regeneration into the AC mains is presently not yet possible with the 9400 servo
drives series. Use the regenerative power for the dimensioning of the brake chopper(s) and
the brake resistor.