Nikola Tesla was the quintessential mad scientist, an unparalleled and unrestrained mad genius, fortunately for humanity he was not an evil or immoral one. His madness and inability to conform to the norms of the scientific community rendered him somewhat of an outcast and recluse. Perhaps it was his intellectual prowess and inability to conform, that led to his keen ability to think outside the box and devise or inspire the development of much of civilizations modern miracles.
Tesla claimed that contact with the electromagnetic charge put him outside his time-frame. He claimed that was able to see the immediate past, present and future simultaneously, but unable to act as he was paralyzed within the electrical field.  A few days later Teslas Lab burnt down, uninsured and with very little resources he was in effect ruined - temporarily at least.
His assistant, by switching off the electrical current cut off his journey in space-time and also saved his life. Detractors speculate that like the rays of light from his pigeons eyes, this phenomena was something only Tesla himself would see, while others believe that it was duplicated years later in the Philadelphia Experiment with hideous results.
Merchant seaman Carlos Miguel Allende  , claimed to have witnessed a similar experiment, also in 1943, of a ship being made invisible using strong electromagnetic force fields as described in the Philadelphia incident.
Whether or not Tesla continued research into space-time or time travel is not certain, he did however issue a statement at the age of 82 that hints he may have.
'I have worked out a dynamic theory of [a] gravity in all details and hope to give this to the world very soon. It explains the causes of this force and the motions of heavenly bodies under its influence so satisfactorily that it will put an end to idle speculations and false conceptions, as that of curved space. According to the [b] relativists, space has a tendency to curvature owing to an inherent property or presence of celestial bodies.... 
Einsteins theory of relativity is what Tesla is referring to when he states - [b] relativists - Einstein delved into 4 dimensional physics when he determined that massive objects cause a distortion in space-time, which we experience as [a] gravity. He basically added a new dimension to the definition of gravity as well as time and space.
1. Interview with Nikola Tesla from 1899
2. The Lost Journals of Nikola Tesla Page 124
3. Tesla and the Aliens
4. The Case for the UFO Page 9
5. Skeptoid Questions the credibility of Carlos Miguel Allende,
6. OCCULT ETHER PHYSICS Page 95
Modern Mechanix Magazine in a 1933 article tells of a 1920 gathering attended by Edison and his associates where Edison demonstrated a photo-electric cell that revealed spirits in a beam of light. The American Magazine in 1920 interviewed Edison and he stated 'I have been at work for some time building an apparatus to see if it is possible for personalities which have left this earth to communicate with us.'