A collection of posts by David Weber containing background information for his stories, collected and generously made available Joe Buckley.
Basically, just as a ship's mass/dimensions affect its acceleration rate, they also affect the speed with which it can make hyper translations. That is, a smaller, "handier" ship can cycle its hyper generator much more rapidly than a great big hairy superdreadnought, and military-grade hyper generators can cycle faster than civilian-grade hyper generators.
There are four basic levels of readiness for a hyper generator:
(1) Powered Down. This one, I think, is probably fairly self-explanatory.
(2) Routine Readiness. In this stage of readiness, the generator's basic readiness checks have been completed, there's a minimal power load on it, but its capacitors are not fully charged, and various safety interlocks are still closed to preventâ?¦ unfortunate accidents.
(3) Stand-By Readiness. In this stage of readiness, the capacitors are fully charged, the interlocks have been disengaged, and the engineer is ready to press the "go" button. However, even after the button is pressed, there is a minimum cycle time while the generator spins its field up to translation capability.
[ David seemed to have trouble counting the day he composed this, so I'll take the liberty of including the fourth readiness state for him:
(4) Sustaining. Running and in hyperspace. -Ed ]
It takes longer to go from Powered Down to Routine than from Routine to Stand-By. Basically, without getting into the detailed numbers (which scale with the tonnage of the ship, from a minimum cycle time of 30 seconds for even a dispatch boat), an 8,000,000-ton superdreadnought requires 4 minutes to go from Stand-By to actual translation. That is, the absolute minimum time for that ship to translate into hyper would be 240 seconds. To go from Powered Down to Translation, the same ship would require 32 minutes.