Do You Need A Pulse Width Modulator
A HHO PWM is a device that will limit the amount of current going to your generator. Not all generators need these. There are quite a few generators that you are best off installing this device on though. If you have a high amperage generator then this can prevent you from overloading the circuit and blowing fuses.
HHO generators will pull different amounts of amps depending on the design and the amount of amperage draw will increase with the temperature of the generator. If your setup is blowing the fuse after you have been driving for a while then you may want to consider installing a pulse width modulator to limit the current available to your generator.