In the kit, you get the new brush motor, speed controller, and associated hardware to make the conversion.
I bought this unit in Dec 2011. It worked like a dream for 6 mos. Had good linear speed control. Then, during a project I was turning for my sister's birthday this weekend, the unit died.
The controller has failed. This was just with occasional use. The motor brushes are fine, the fuse is fine, reset switch is fine etc. I design custom controls for a living, so I knew my way around this controller. The warranty was 30 days. I'm out $100.
I hate to disparage any tool or company because no company nor product is perfect, but I'd feel bad if anyone here bought this kit and experienced the same thing I did.
I put the original single speed induction motor back in the lathe to finish the project. I don't care for moving the belt from pulled to pulley, so I believe I'll pick up a name brand variable speed lathe down the road.
This isn't the first time I've had an issue with a PennState product. I believe I may shop elsewhere from now on.

http://www.pennstateind.com/store/TCLVSKIT.html
I would think it the speed controller broke, you could very successfully replace it with any of those off-the-shelf router speed controls.
either of these (15- and 20-amp models) would work considering Penn State says the motor is a 1/2 HP motor (about 3.5 Amps max):
http://www.mlcswoodworking.com/shops...d_control.html
Just add an AC plug to the leads from the motor and plug into the controller.
P.S. one of the reviewers on the Penn state web site said that he has several of those and dust in the power switch is a recurring problem, apparently the switch is not sealed. Try blowing out the switch with compressed air or if you know your way around electronics, bypass the switch. Or use an ohm-meter to check the switch.
your profile says you do custom controls but I'm not really sure exactly what that means. could be electronic controls but it might not have anything to do with electronics.
I design custom electrical control panels and have a degree in engineering electronics. The unit had no dust, I'd kept up on that and kept it protected. The switch was fine, I tested it.
Yes, I can replace the controller, but my point for others was to beware of this unit in that it's weak.
What was really weak to me was the motor itself. Itb does fine for pens but when I put a 12 inch bowl blank on mine, it did not have the power to work it except for tender touch-n-go type of cutting.