There are 2 basic types of electric motors, Alternating Current (AC) and Direct Current (DC). Both have been around since early 1800’s. AC motors are the most widely used but the DC motors are the ones most commonly in golf cars.

An electric motor consists of a group of 'field windings' of electric wire that surround a conductive center, the armature. The field windings constructed in such a manner that it can rotate freely. Electric current is passed through the field windings and the armature causing a field of electromagnetic flux. This flux field exerts force on the armature causing it to rotate. This rotation is the motion that drives the electric motor.

DC Series Electric Motors

The distinguishing design of a Series Wound DC motor is that the field windings and the armature are electrically connected in series. Torque and speed control are achieved by a ‘throttle’ that varies the intensity of current flowing through the fields and the armature. Series wound motors offer very high starting torques and good torque output per ampere, but have generally poor speed regulation. DC motors have high torque at low speeds and decreasing torque as the speed increases.

The field windings of series wound golf cars have only 6 turns or so of copper wire as big as your little finger. This large gauge wire and can handle about 300 amps. There are 4 sets of these field windings in these DC motors. A large field force turns armature and drives the golf car and everything with it. The speed of a golf car is controlled by varying the current in the field and armature.

This is how the golf cars were designed for many years. But there are some problems with this design. The largest problem was the ‘Free Wheeling’ nature of this system when the golf car goes down hill. The only thing to keep the golf car from going dangerously fast (if the hill is steep enough) is to use the Car’s brakes. As accidents and incidents piled up, golf car Manufacturing companies became increasingly concerned about creating an electric golf car that has built in safety features. Enter separately excited field DC Motors.

Separately excited field DC Motors

The separately excited field DC Motors are different from Series Wound DC Motors primarily in the way the field is wound. Series motors create the electromagnetic field using very large wire and a high amperage.

It so happens, however, that you can get the very same flux field with much smaller wire and much less current flow by making many more turns. A field of flux, then, is a function of “Ampere (current)-Turns”.

The difference is very significant! A series wound field has a current of, say, 300 amps. The same separately excited field has a current of only 20 amps. It has been known for a long while that a computer programmed controller could be built to control a 300 amp field, but the components and size would be unacceptable if only from a cost standpoint. The 20 amp current of a separately excited field motor is a different story. A computerized program controller can be designed to provide a wide variety of control over the fields to result in a wide variety of performances. And the most important thing is that it could be built within an acceptable manufacturing cost.

So if a controller can be built to manipulate the electric fields of a DC motor, then we can Control the motor to make it do the things that we want it to do. And from this possibility came all these new innovations to modern day Electric golf cars. Rollaway Protection, downhill Regenerative Braking and Torque/Speed Controls for a wide variety of conditions are now available. The constant implication, of course, is that Safety features can now be created.