Appendix D: Optional equipment
76 SC9000 EP medium voltage drives IB020001EN—February 2016 www.eaton.com
The brushless type synchronous motor has distinct 
advantages over the brush-type. Maintenance of the 
brushless type is considerably simpler. The brushless type 
does not require cleaning the slip ring collector, repairing 
damaged or corroded slip rings, inspecting and replacing 
worn brushes, etc. In addition, brush particles abraded from 
the brushes and loose in the motor frame can deposit on the 
motor windings, affecting insulation life.
In addition, the brushless type is more suitable for use in 
adverse environmental conditions. Maintaining slip rings and 
brushes under conditions like those found in chemical plants, 
where steam, oil or corrosive gases are present, is very 
difficult. Brushless motors designs for pressurized or 
explosion-proof requirements are much simpler than with 
slip rings and brushes.
The SC9000 EP drive system can include control and 
excitation for brushless synchronous motors.
SC9000 EP synchronous motor control
The SC9000 EP Synchronous Motor control system provides 
both stator and rotor control and power. The SC9000 EP 
Adjustable Frequency Drive powers and protects the 
synchronous motor’s stator windings, while the separate 
power and protection system provides the rotor windings 
excitation. Figure 81 shows the SC9000 EP functional block 
diagram for brushless synchronous motors.
The SC9000 EP directs the field exciter, based upon 
configuration and settings parameters established in the 
drive application software. For more information about the 
application parameters, see Chapter 5, Parameter Group 
G1.15, which includes parameters for enabling or disabling 
the control, choosing control modes, setting control loop 
constants, and so on.
Brush-type synchronous motor control
Although the SC9000 EP Synchronous Motor Control system
is designed for brushless synchronous motors, Eaton also 
offers control systems for brush-type motors, powered by 
Ampgard Medium Voltage Starters. For more information 
about these systems, refer to Eaton IB 48045, Instructions 
for Mark VI Solid-State, Brush-Type, Synchronous Motor 
Controllers.
O&M technical references
For detailed information on your Synchronous Motor control 
system, refer to the O&M manual, publications:
IB48045 Instructions For Ampgard
®
 Mark 5.5 Solid-State,
Brush-Type, Synchronous Motor Controllers
Figure 81. SC9000 EP brushless synchronous motor control