Comparative Test Results of a Brushless DC Starter Generator vs. Traditional Starter Generator with Brushes

This paper provides comparative test results for a brushless starter generator versus a brushed starter generator of equivalent nameplate rating. Key starter generator performance characteristics are measured by test and compared for each type of starter generator. These comparative performance parameters include:

• Generator output voltage versus load current versus drive speed
• Generator maximum output power capability versus drive speed
• Self excitation start-up capability (with no external source of control power)
• Efficiency during generate operation
• Efficiency during start operation
• Performance for high transient load applications
• Power quality, including ripple voltage and noise on the 28VDC bus
• Gear box torque induced stress during engine start
• Short circuit and over-load protection
• System weight
• Overhung moment for starter generator unit