Est. 1963

Here is a summary of the advantages of AC motors over DC in a golf-utility vehicle:

• Faster acceleration
• More power under a load
   (think 4 passengers, climbing a hill)
• Improved downhill braking
• Higher top speed
• More efficient regeneration
• Less Maintenance Cost
• Less energy used to recharge and to operate

Anyone who has driven the classic 36 and 48 Volt DC powered golf and utility vehicles knows that they slow down going up hills...the steeper the hill, the slower the speed. The same is true for a DC utility vehicle carrying a load...say a 4 passenger. The more the load, the slower the speed. With the new Yamaha AC powered electric vehicles, the acceleration and speed under load an up hills will be the most noticeable difference.

For those who want more details, here is a technical overview:

AC Electric Motors versus DC Motors

Here is how it works: The DC (direct current) power of a 48-volt battery pack is inverted to a 3-phase AC signal to power an 18hp, 3-phase, AC induction motor. The motor bolts right up to the existing transaxle. The Yamaha AC powered vehicles use a controller designed and built by Toyota and is DC to AC inverter/controller combo. It is somewhat similar to the DC electronic speed controllers found in modern golf carts and utility vehicles but it is a tad more complicated. It not only changes the DC to 3-phase AC, and back again for regen, it also controls the motor speed according to pedal position. AC delivers a lot of power under a load, like climbing hills with four passengers aboard, and it provides significant electric motor braking down to ½ mph. In other words, the speed of the car is proportional to the position of the pedal, uphill & down. Features like top speed and regen characteristics are programmable. The performance characteristics of AC are a leap above its DC counterpart, even given the regen features of modern DC motors & controllers. AC has been slow to come to the golf cart market because of the engineering & programming complexity of the inverter/speed controller and because of the cost.

The AC motors start to make sense when more voltage is used and high end speed is desired. The AC motors are capable of higher RPM’s and can easily produce higher speeds, their brushless design means less maintenance cost, the reduced friction increases efficiency, adding to the vehicles range.

An AC motor can give a wider band of power performance generous low end torque along with superior high end speed. In most DC applications, there is a trade off with either low end torque motors or high speed motors, sacrificing one over the other.

The lift truck industry has moved almost exclusively to AC motors for electric forklifts for most of the reasons listed above. Commercial users appreciate the improved range and lower maintenance cost.

A recent independent analysis by utility Southern California Edison (SCE) demonstrated that an AC powered electric vehicle, with an AC Drive, full-time regenerative braking can be as much as 39 percent more energy efficient than traditional DC-powered vehicles.  According to SCE’s results, energy efficiency improved by well over 30 percent with the AC model. The AC motor also enabled the vehicle to maintain higher performance than DC-powered vehicles as batteries lose energy over the course of daily use.   An AC powered utility vehicle requires less energy to charge and operate, minimizing the vehicle’s "carbon footprint" and reducing hazardous waste.