I’ve been working with D&D Motor Systems to upgrade the motor on my CitiCar. I’ve gotten to learn a bit more about my car while I was gathering information to pass along to them.

I heard back from them today. They offered a motor with part number ES-40D-56, and provided an outline of the motor to review. It looked like the motor was 11.45 inches long, and 6.7 inches in diameter. It was much longer than my 9 inch motor. It will just barely fit within the space that I have available.

One thing I noticed is the placement of terminals was different. All of the terminals are the furthest away from the motor control. Given the wires were at the exact length needed, I would need to replace them with longer wires. I’ll need to upgrade my motor controller to use the new motor, so I may just put it in the battery box next to the terminals and use really short wires. After all, I’ve seen 1D10CRACY do the same thing with his controller placement in one of his videos, and it looked like a really efficient way to set things up.

They asked me to make sure that the pilot on the motors mounting a plate along with the four holes used to mount the plate to the trans-axle were the same as my existing motor.

I must admit, I’m a bit confused about this. I’m not sure what an “A Plate” is, and I didn’t see any measurements for the pilot screws Maybe there are measurements, but I am unable to identify them. I was going to print out the outline, but I found that it wasn’t at 1:1 scale to line up with my motor or axle to compare.

The motor can run off of either 48 or 72 volts. This is great since I’ve already purchased some 48 volt lithium batteries. But now I’m wondering if I should look into a 72 volt system. The problem would be that the 48 volt batteries would sit, doing nothing. I found a few things online that have my concerned about the voltage, as well as in the motor outline itself. It seems this may actually be a 36/48 volt motor.

• A forklift repair shop offering to repair it and said it was 36/48 volts
• Golf Cart Catalog was selling it for $735 as 3.2 Non-Peak HP at 2825 RPM 36 Volt Motor, Series wound.

The price for the motor is $635 + freight with a lead time of two weeks. The price motor seems to be around the ballpark figure I was considering. I’ve got so much stuff with a long lead time, that waiting two weeks before they can build the motor isn’t going to be a problem.

If this is the same as the motor on golf cart catalog only rated for 2825 RPM, it would appear this would lower my cars maximum speed from 36 down to 26 mph. At almost half the horsepower, I imagine it wouldn’t have any pep trying to accelerate.

I’m wondering if my math is off, or if I’m just not thinking about electric motors in the proper way. I keep thinking that motors have got to be more efficient today compared to 45 years ago, but in the end, they are still composed of about the same amount of copper. I simply don’t want to buy a new motor if it’s worse than what I have. Maybe it’s the motors controller that makes all of the difference.

I asked for more information

• What are the specifications? RPM/HP/Amps
• What is the type? Series, shunt? Does it support regenerative braking?
• Does it have a heat sensor? How hot is too hot?
• Is it compatible with a speedometer cable? Is there a way to detect how fast it is spinning?
• How far apart are the pilot holes in the outline?
• Are there recommended controllers for this motor?
• How heavy is it?

Now that they have no more need of additional details about my car, I can put the original motor back on until I have everything to replace the drive train. That thing was heavy. Maybe I should wait a few weeks…

Delayed

After a few days, I called over to the front desk. I hadn’t heard back from the engineer and I thought maybe he had sent me a standard part number that sales would have all of the specs for. Perhaps I could just go through sales to get the info I needed and order over the phone. I called in and… they paged him. He seemed friendly and all, but I felt horrible for bothering him. Just my luck, a part used in the motor has been used up, and the lead time is three to four weeks now. He explained that he hadn’t gotten to his email over the past few days to see my questions on the specs and that he’d look over it and get back, if not tomorrow, then after the weekend.

I must admit, the company seems a bit more on a personal level. I feel that most companies are a faceless corporation. With D&D Motor Systems – I’m talking with people. I’m talking with an engineer – directly – one on one. Like – me of all people… no chain of command of twenty or so managers, team leads, salesman, and what not – where details are lost and conversations are difficult to have in real-time.