i have many accounts like this, have you tried the yellow smoothie wheels? they help a little, but one stick and its all over.
try taking some shims out of the caster wheels allowing more pressure on the drive tire in hope to not get stuck.
the fuses would be more likely to blow when the motor is stalled
assuming your talking about the blade fuse right on the traction amp. are your batteries changed out when dead, or charged in the jack? the reason i ask is i am positive your blown fuses are not a normal occurrence, and am also sure there is some other not so obvious cause here.. i know its hard to keep triple jacks up and running due to the major weight and work load involved, in my opinion they should only be trusted to the best operators due to the small room for error involved. if the operator are a slam n go type they should be on a single!
with a good slow cautious driver the triple will still run circles around the other options. i have one customer that has crowns, and raymonds. both with the same problems. it really boils down to how its used.