What were the effects of the slave revolts?
Slave revolts occurred throughout the New World in the eighteenth and nineteenth centuries. Because your question is very general, I would draw your attention to the important differences between the results of revolts in Brazil and the Caribbean and those which occurred in the United States. There is also a difference between revolts which occurred on ships, which tended to be more effective, and those which occurred on land, which were more likely to be put down by those in power.
Well-known revolts in South America and the Caribbean include the Bahia revolt in Brazil, the Morant Bay Rebellion in Jamaica, and the most successful revolt of all, the uprising in Haiti led by Toussaint L'Ouverture. With the exception of the Haiti uprising, which resulted in independence, these revolts were generally put down swiftly and violently.
Governor Edward John Eyre's response to the Morant Bay Rebellion resulted in the deaths of 439 black people, 600 floggings, and around 1,000 homes being burned to the ground. There was controversy in England over Eyre's actions, with intellectual figures such as Charles Darwin and Thomas Huxley condemning him, while Thomas Carlyle and Charles Dickens defended Eyre's need to restore order.
In the United States, there was also violent retribution against blacks after slave revolts, though legislation was also enacted to deal with the threat of insurrection. However, most American revolts were foiled before they could be carried out. Gabriel Prosser's intended revolt in Richmond, Virginia in 1803 was spoiled by a black cook who informed on him and other participants. Denmark Vesey's intended revolt in Charleston, South Carolina was also foiled. However, in 1831, Nat Turner did carry out a revolt in Southampton County Virginia which resulted the deaths of 65 whites, including children.
Before Turner's rebellion there had been talk among legislators of possible abolition of slavery. After the rebellion fear of blacks was palpable, resulting in more severe actions to control black people. The Fugitive Slave Act of 1850 was partially in response to fear of, not only of slaves, but also of free or escaped blacks. Slaves who were found to be off of plantations without written permission from their owners could be severely punished. Prior to Turner's revolt, slaves had more freedom to roam. Also, groups of blacks found to be congregating were deemed suspect and were often broken up and sent back to their respective plantations. Prior to Turner's revolt, blacks were allowed to congregate, particularly for religious services.
Generally, with the exception of Haiti, revolts led to violent retribution against blacks -- both free and enslaved -- and legislation intended to circumscribe their lives (e.g., ability to congregate, leave plantations, learn to read) even further.