Racking the primary wort will re-oxygenate the liquid, allowing the yeast to get back to work and give you a good secondary fermentation. The original fermentation may have run short due to low oxygen in the wort.
I used to have problems from time to time with abnormally short fermentations, then I learned (after gentle coaxing from far more wise brewers) the value of aerating wort.
Cheers!
I concur 100%.
I finally started using pure oxy with a stainless steel aquarium stone.
What a difference. Who needs a secondary?
Cheers,
knewshound