This is a 1980 vintage resistor coil drive system. To read about how this early type of speed control works read here >
http://www.cartsunlimited.net/why-co...-drive---.html
The very first 48 volt drive system appeared in 1995. This cart is 36v. To run 48v for more speed and torque the cart will need to be converted to modern solid state speed control here >
http://www.cartsunlimited.net/conversion-kits.html