it might be that the shield regenerating takes up all the power.
the biggest possible shield isn t always the best... - for example:
when you mount a 100k shield on a zoner whale - and you also happen to have a heavy CM, NPCs can shoot CDs at you - and fire at your shield.
the powerplant will try to replenish the shield ( taking up power ) while the CM will try to intercept the CDs ( taking power, too )
resutling in the whale having NO power and even needing more power to replenish the shield than it generates. - then the ship even stops moving at all ( no impulse, no steering )
as long as the shield is attempting to regen, the ship will be totally immobile. - at that point, any gun that does more damage than the shield regen can keep the transport mezmerized. - a way to fix it is to mount a shield with less powerneeds.