Silicon Productions
The MGB Electric Sports Car
Analysis by Warren Winovich
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As a point of comparison of the acceleration capability of the MGB electric sports car, the calculated value for the quartermile run is given in figure 8 with measured times for several homebuilt and production electric cars. The calculated value for the MGB electricpowered car for the quartermile is
Critique of the analytical methods employed. The application of the general equations of motion to determine the performance is wellfounded by tests in which economy and range between charging are compared to calculated values. Agreement in the range of 10 % descrepancy is deemed acceptable. The degree of agreement depends on the reliability of the values from specifications of designs adopted for the electric car.
For the present study, the greatest uncertainty is the specifications of the induction motor installed in the MGB. The estimate used here is based on a visual examination of the installation  aided by the fact that the motor had a specially wound stator to accommodate higher currents for a 70volt, threephase system. A 15kW, threephiase, fourpole design was assumed based on scant information. Further, it is tacitly assumed that starting torque is limited to three times rated torque. The ratio between starting torque and rated torque for standarddesign induction motors is quoted as 3:1; however, premiumdesign models are available with a ratio as high as 6:1. For the present study, a conservative decision was made to adopt the lower ratio for the installation in the MGB electric sports car. The result is rather low ( but, acceptable for practical driving ) acceleration performance. Note that EV drivers placing high in dragracing competitions have cars with twospeed transmissions, shift at optimum speeds, 'burnout' tires before their runs, and frequently install smaller battery packs to minimize driving weight.
Concluding remarks. An analytical procedure has been used to determine the performance of an MGB electric sports car. The design features incorporated in this conversion represent the modern trend to use induction motors. A unique feature of this conversion is the lowvoltage inverter/control that provides a conventional driving sensation with regenerative braking. Results are summarized below.
economy of energy usage  246 whrs/mi @ 50 mph, highways 
range between charging  20 miles @ 50 mph, 100 % DOD 
12 miles @ 50 mph, 60 % DOD  
acceleration performance  0  30 mph: 
0  50 mph: 

¼  mile 
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