To generate engagement on your poll, you may want to encourage users to vote on your poll once every X hours/days.

To configure that your voters can vote more than once in your poll, follow these steps:

1) Open the poll creation form

2) In the "Allow voting again" drop-down, select the time after which the user can vote again (you can select between 1 hour, 6 hours, 24 hours or a week)

3) Click Save

Note that when users vote again in the poll, the previous vote is not removed, so in this way users can contribute multiple votes to the poll over time.