Operation
Theory of Operation
242 MagneMotion
Rockwell Automation Publication MMI-UM007F-EN-P - September 2020
Block Level Power Management
When the internal propulsion bus reaches +805V DC, current begins to ramp in the coils of
blocks that are available to allow the motor to absorb and dissipate unused power due to
regeneration within itself or coming from other motors that are connected to a commonly
shared +458–747V DC power supply. A coil block is defined as available and is used to dissi-
pate power within a motor if its neighboring blocks (upstream and downstream) do not have
any part of a magnet array over them. A neighboring block can be within another motor as
would be the case for the first and last blocks within a given motor.
The current in these available blocks ramps linearly to 15 A over a 20 volt range from +805V
DC to +825V DC. The coil current remains constant at 15 A for voltages above +805V DC
and drops to zero for voltages above +830V DC since all inverters are turned off. This behav-
ior is shown in Figure 6-10.
Figure 6-10: Individual Block Current vs. Internal Propulsion Bus Voltage
With a nominal block coil resistance of 4.5 Ohms, the dissipated power is 1 kW per block
when the 15 A current level is reached and remains at this level up to +830V DC. The dissi-
pated power vs. the internal propulsion bus voltage is shown in Figure 6-9.
Figure 6-11: Power Dissipation Per Block vs. Internal Propulsion Bus Voltage
0
2
4
6
8
10
12
14
16
800 805 810 815 820 825 830 835 840
Current (A)
Internal Bus Voltage (VDC)
0
200
400
600
800
1000
1200
800 805 810 815 820 825 830 835 840
)W(kcolBrepdetapissiDrewoP
Internal Bus Voltage (VDC)
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