Electric Vehicle Conversion - AC Project
Upon completion of our conversion of the Chevy S10 pickup with a DC motor, we started thinking about a new conversion using a higher efficiency AC motor.
In addition to the higher efficiency, AC motors require less maintenance because they do not have brushes. We spoke to a Baldor representative we were acquainted with about the possibility of making an AC motor to our specs. Baldor had previously been unwilling to build a motor for an electrical vehicle conversion but they saw the way we mated our DC motor to a fully functioning manual transmission in our Chevy S10 conversion and they decided to build an AC motor to our specifications. We made a conscious decision to build a larger motor that would work in a full size pickup truck. Our goal was to build a truck that could function as an “every day “ commuter but also work as a delivery truck in our business.
We purchased a 2003 Chevy ½ ton extended cab Silverado pickup truck. The motor Baldor built for us is a 3 phase induction motor. It is rated 72 volts AC at 60 cycles, 50 hp, 150 ft lbs torque and 362 amps continuous rating. The motor has large 6312 bearings. Large bearings carry more load and have lower internal ball bearing speed due to the larger circumference of the bearings. Lower ball bearing speed results in longer bearing life. The motor is also totally sealed which eliminates the chance of dirt and debris entering the motor. The motor is mated to the original 4L60E automatic transmission with an OptiShift controller from Baumann Electronic Controls.
The transmission will shift at our predetermined rpm points for maximum power and power efficiency. We are using a Wicom BMS and a TC charger. The charger will charge at 30 amps on 230 volts AC. We are using 64 Hipower LiFePO4 200 amp hour cells.
The battery configuration is 2P32S for a nominal voltage of 102 volts DC at 400 amp hours. The battery boxes are mounted underneath the cab and bed between the frame rails with clear plastic covers for protection and visibility into the boxes. There are no batteries in the bed of the truck which allows for more room for hauling cargo. We are using a 1238R-7601 Curtis controller.
Vacuum brakes are powered by a 12 volt DC Gast pump. The heating system is from Electric Car Company in Midvale, UT. The truck has power steering, air conditioning and a 12 volt DC alternator that charges the existing 12 volt system. The controller allows the motor to idle at 400 rpm to maintain the torque converter and to keep the system pressurized. While idling, the amp draw is 9 to 17 amps depending on transmission oil and power steering fluid temperature which affects viscosity. As a result of the 400 rpm idling, there is no lag when starting to accelerate. It also allows the power steering to operate even when standing still.
We have had the truck on the highway at 70 mph although the optimal speed is 55mph or lower. When the truck is running at around 45 mph, it uses only 5 amp hours per mile. The truck weighs 5945 lbs.
Here are some of the specifications of the Baldor motor:
- Manufactured in the USA
- 1 year manufacturer’s warranty
- Double shaft design with both shafts measuring 1.625 inches
- 6312 sealed bearings on both ends
- 94.5 % efficiency rating
- 72 VAC at 60 cycles, 50 hp and 150 ft lbs torque at 362 VAC continuous rated
- Totally Enclosed Non Ventilated Air Over (TENVAO) design
- IP54 with some IP55 features
- Less maintenance with the large bearings and no brushes
- Quaduature encoder 2 channel
- Weight = 490 lbs
- NOT RECOMMENDED FOR VEHICLE WITH NO TRANSMISSION/DIRECT DRIVE APPLICATION
Click on the image below to start the video.
Click here for additional technical specs (downloadable Zip file. Unzip to access PDF files)