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AD&P; > June 2013 > FEATURE > GM Building Motors in Baltimore > Gary S. Vasilash > gsv@autofeldguide.com u The stack of laminations for the rotors. Magnets are inserted into the slots on the top. Note just right of center how there is a discernible vertical line that is not straight. That is deliberate. It is designed to help shape the magnetic feld created. Larry Nitz, who heads up global electrifcation engineering for GM, says of their approach to motors, "We will build, we will buy, and we will partner where we see ft as part of our portfolio for electric vehicles." He also points out that since 2003 the company has been creating an extensive capability when it comes to designing, developing, processing, and validating electric motors and batteries. A key reason why they're building the Spark EV motor at GMBO is because they want to have the necessary understanding of what it takes to build a motor: When they go out to the supply base, they're speaking from a position of frst-hand understanding. As Savagian puts it, "There are subtleties we can only learn by doing." Speaking of frst: GM is the frst U.S. automaker to be producing motors for EVs. While the number of motors that can be produced in the GMBO eMotor building is something that GM isn't revealing because the number of Spark EVs is also being kept inside, 24 the factory is setup with a sufcient amount of fexible automation supplemented by manual operations such that it seems that it would be fairly easy to ramp up to higher volumes. This is not a low-volume arrangement by any stretch of the imagination. For example, the bending of the square copper wires that are used in the stator (128 wires) is performed in robot-based cells; there are nine diferent shapes produced (two of those shapes are welded together so that there are eight part numbers). The wires are manually inserted into stator stack. The ends of the wires are automatically welded. Varnish is robotically applied. The stator is manually bolted into the housing. The rare-earth magnets in the 10 silicon-iron laminate sections that are stacked to create the rotor core (400 magnets are used per motor) are manually positioned (as are the stacks, which are slightly ofset for purposes of controlling what's called "torque ripple": Nitz explains that to minimize vibrations in the electric motor, the magnetic feld has to be specifcally tailored, so the stacks are built up such that they create a herringbone pattern on the OD and there are precise features stamped out of the laminates to control the fow of the magnetic feld). In mid-April 2013, when Governor Martin O'Malley comes to the plant for the ofcial start of production ceremony for the motor (in full campaign mode he tells the assembled, "The only way to strengthen the red, white and blue for the future is green!"), the capacity of the plant is evident. "We're early in the launch process," plant manager Bill Tiger says. One gets the sense that they're ready to go full-bore into the production process. Should the volumes of the Spark EV be high, the people at White Marsh are prepared. The drive unit for the Spark EV. The planetary gear set to the right of the motor is actually a part used for GM six-speed transmissions. This is one way that they're able to keep costs down for the unit.