<p>This paper visualizes overvoltage regions using voltage vector diagrams in motor drive systems. The reflected voltage caused by an impedance mismatch in the motor drive system results in overvoltage. The double-pulsing effect occurs when the oscillation of the overvoltage does not decay before the next pulse arrives. This induces a higher overvoltage than that with a single pulse, causing electrical stress that leads to insulation breakdown. The relationship between the overvoltage in the inverter and the motor is analyzed through the reflected voltage in this paper. The overvoltage caused by the double-pulsing effect is calculated using various factors. Then it is normalized using a voltage vector diagram and graph according to modulation schemes. The vector diagram and graph of the double pulsing effect are verified through simulation and experimental results.</p>