In Helena's words, the time machine is essentially a "temporal consciousness transfer engine". It has a rather psychometric effect, allowing the user to inhabit the body of someone in the past, specifically for 22 hours and 19 minutes.
In "Endless Terror", Paracelsus repaired the time machine and powered it with the Tesla Targetting Coil. He then combined it with Pierre-Simon Laplace's Telescope, Theodsius of Bithynia's Sun Dial, and Karl Schwarzschild's Pocket Watch to physcialy send himself back in time. He had the time machine set for June 10th, 1541. Later in the same episode, Claudia re-created Paracelsus' time machine except had Steve use Jack Lalanne's Stationary Bike as a power source for it in place of the Tesla Targetting Coil.
When H.G. completed the machine, she used it to travel to Paris, 1899 on the day her daughter, Christina was killed. That year, she chose to leave her daughter in the care of her cousins. However, Christina came down with a fever one day so Sofie, the house keeper, told Christina to stay in bed. That same day, men broke into the house expecting it to be empty; Sofie tried to fight them off, but Christina was killed in the fight. When one of the killers was finally caught, he described the fighting style Sofie used as being Kenpo style martial arts, a fighting style H.G. favors, but Sofie had no memory of any of this. After hearing this, H.G. knew that some time in the future she must've found a way to go back in time and actually become Sofie. That was when she began work on her time machine and when it was finished she attempted to use it to save her daughter's life, but despite all of her work she couldn't and Christina was killed.
H.G. Wells' Time Machine is not, as in her novel, a physical transport device carrying the user(s) back (or forwards) in time, rather it is based on Gestalt psychology principles, and employs the "web" of the collective unconscious to allow the user to target and inhabit a known individual at a specific time in the past. The maximum duration of the trip through time is 22 hours and 19 minutes; as soon as this time is over the user(s) return to their own bodies in their own time period. However, if the time machine is damaged while in use the user(s) consciousnesses will be lost forever as soon as time runs out.
The maximum duration of the trip through time, prior to it being damaged, is 22 hours and 19 minutes. This totals 1339 minutes, which is perfectly divisible by 13.
When HG created this artifact she never intended for duration of its effect to only last 22 hours and 19 minutes, but she never could figure out how or why her time machine only lasted that long.
HG's inspiration for this artifact was the idea of people living past lives, e.g. a woman who claimed that she was Scottish farmer 100 years ago and she could even point out the exact place she lived.