Surge Testing of Motor, Time for application of surge

[Naumaan]

Hi,
We want to use a PJ high frequency surge tester for surge testing of motors, which can give 50 surges per second upto 40 KV.
We use the voltage levels for surge testing which are given in IEEE-522.
The way to apply voltage is that it has to be started from 0V upto the highest voltage of surge testing. (Am I Right?)
But what is the rate of increasing the voltage and for how much time the peak surge voltage is to be kept across winding?

Thanks in advance...