Rockwell Automation MDF-SB1304F Kinetix 6000M Integrated Drive-Motor System User Manual
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132
Rockwell Automation Publication 2094-UM003A-EN-P - May 2012
Appendix D
Kinetix 6000M System Sizing
Step 3: Confirm that all IDM units connected to each IPIM module
will have sufficient control power voltage.
This is a complicated calculation to do accurately for the same reasons stated in
step 2. The purpose of this step is to confirm that the last IDM unit in the daisy
chain has sufficient voltage to operate. An estimate of the applied voltage
assuming all the IDM units are at the end of the total cable length can be
calculated as shown below. This calculation results in a very conservative
estimate. It is conservative because it assumes the load current for all IDM units is
carried by the total cable length, which overestimates the voltage drop on the
cable significantly.
Where:
V
N
= voltage at the last (
Nth) IDM unit (actually at all IDM units in the
simplified system)
I
L
= load current calculated in step 2
L
t
= total hybrid cable length out to IDM unit
N in meters
R
C
= resistance of the hybrid cable control power conductors in ohms/
meter (0.0274275)
A better result may be obtained if step 2 and step 3 are repeated iteratively. The
voltage determined for step 3 should be equal to the voltage value used in step 2.
This gives the most accurate value for the simplified system.
IMPORTANT
Confirm that V
N
is greater than the minimum voltage specification for the IDM
(32V DC). See the Kinetix Rotary Motion Specifications Technical Data,
publication
.
V
N
= 42 - I
L
* L
t
* R
C