Newbie is right. The Grado hum problems are well-documented.
I run a Grado Sonata on my Rega Planar 3. I was told that it would be hit or miss with each individual Grado as to whether there would be hum if used on Planar 3's. I have a tiny bit of hum as the cartridge gets near the end of the LP, but nothing so bad as to warrant a cartridge swap. Some people with Planar 3's report significant hum.
I am virtually positive that there is a "hum eliminator kit" for the Planar 3's that is made precisely for the purpose of addressing the Grado hum problem, but I do not know who makes it (or whether it is still available).
I also have a VPI Aries. I ran the Sontata on the Aries for awhile and never had hum. Given that the motor on the Aries is outboard and exposed, I don't know what could be done to shield the motor from the cartridge. There is a plastic motor cover that comes with the table which sits over the motor and plinth, but I do not know whether it would help (and it looks ridiculously out of place on what is otherwise a beautiful turntable).
Hope this helps.