Power Supply Voltage/ballast resistor

I have some Vexta PK266-01a-C23 steppers that I will be driving with
Allegro 5804's. The Vexta's are rated 7.4 volts 1A 7.4 ohm. I
assume that the power supply voltage - 7.4V (Vexta rating) would be
the voltage drop of the ballast resistor. To further that would be
the resisance of the ballast resistor would be the voltage drop
acroos the ballst resistor/1A (Vexta Rating) . SO for a 12VDC power
supply there would be a 4.6 volt drop across the ballast resistor at
1 A would be 4.6 ohms ? 5 Watts?