Hello,
I'm experiencing the same thing currently. Did you find a fix? My set up goes from 5 mv solar arrays through glass cable to an MFSU. This then goes directly through a mv transformer block, into glass cables which connect into a row of four advanced machines. Each machine has a redstone torch placed under it, and begins to power for several rpm's etc until about a fifth of its capacity, then begins to power down again.
Any idea what's causing this?