Place the raisins in a small bowl and cover with boiling water. Allow to sit for 5 minutes and then drain.
Fit a food processor with the grating blade. Cut the carrots in half and place in the feed tube so they are lying on their sides. Process in batches. Place the grated carrots in a medium bowl, add the lemon juice and toss.
For the dressing, whisk together the sour cream, mayonnaise, sugar and salt. Pour the dressing over the carrots and add the pineapple and raisins. Toss together and serve.