In some instances it is advantageous to immediately repeat the same weld sequence on a spot weld. This is usually done in an attempt to grow the nugget larger or to permit a brief cooling of the part. Immediately at the end of the weld sequence one or two cycles of cool or current off are introduced with full force maintained then the original weld sequence is repeated.
The number of weld sequences can be repeated as desired with a brief cool in between each. When done the weld sequence ends with the normal hold and off to cool down the weld under pressure and end the process. This process can be called impulse or pulsation depending on the control you work with.