All-Encompassing EV Conversion Supersite Diary (Entry 173)

Monday November 29, 2005 - Etek Motor Placement

Update:

Today, I started the task of mounting the Etek electric motor securely into the mortorcycle frame. The end goal is to mount the new motor securely, safely, and in correct alignment for the operation of the final drive chain, while leaving as much room as possible for mounting the four large and heavy traction pack batteries. This step involves stepping back and really thinking about the possible ways of accomplishing the desired results.

The first order of business is to properly place the Etek electric motor within the frame of the motorcycle such that the drive sprockets are in alignment and the smallest amount of frame space is taken up. Any remaining volume within the frame tubes of the motorcycle will be required for the (4) 12 volt Optima lead-acid traction batteries needed to power your ECycle.

Everything proceeds slowly at first, and then somewhow it just starts to come together. Remember that room must be left to mount things such as contactors, throttle pot boxes, and the main motor controller. Most of these parts do not like water and so must be placed where they can be easily protected from the elements, but still have access to the airflow required to cool them.

Spacers between the frame and mounting plate are used to position the electric motor within the frame of the motor cycle. The mounting plate "pivots" on the original (long) engine bolt that passes through both sides of the original frame. because this bolt's mounting holes were installed at the factory we are sure that this bolt is exactly 90 degrees to the face of the mounted sprockets. Moving our new engine assembly along the shaft of this bolt and maintaining the position using tubular spacers will ensure exact left<-->right alignment within the motorcycle frame. Temporary links are used to lock the new motor mount into position and to prevent movement when torque is applied.

Getting the correct alignment of the chain sprockets is critical to the success of your ECycle project.

The original bolt from the lower motor mount is used to align the new Etek electric motor with the rear sprockets. An aluminium plate (1/2" 60601-T6 Alloy) is used to bolt the motor to. A hole drilled into the tab on this plate lets the long engine mounting bolt pass through, and acts as a pivot point that defines the radius starting point for the "swing" of the mounting plate. We are trying to place the center of the electric motor's output shaft in a line defined by the intersection of the rear sprocket center point and the swing arm bolt. This will keep the drive chain in alignment during use as the swing arm moves up and down with road shocks. Another plate for the commutator end of the motor will be setup in the same manner on the engine bolt. Finally, these two plates will be aligned and bolted together to form a small, rigid "cage" to house the electric motor. To seperate the two plates I will use equal length steel pipe of about 6" in length to keep the two plates parallel. Inside these pipes will be 1/2" plated bolts to bring the unit all together. The completed assembly will be strong, light, and will not allow the drive unit to twist in the frame when torque is applied. Pivot the assembly to the alignment point for the chain and and then with small links attached to the frame of the motorcycle, lockeverything in place. If through use I find that the chain is not aligned correctly, I can simply add spacers along the length of the main mounting bolt to shift the drive unit left or right. Different length attachment links will allow the motor to pivot along the other plane, and when I finally find a suitable position, I simply add more attachment points to prevent movement. each motorycle will be different but the idea is the same. get the chain and sprockets into alignment and the front drive sprocket positionned where its is within the arc of movement when the swing arm is in use. All chain driven motorcycles have the same problem of geometry to overcome...

Various viewpoints of the motor mount mockup to this point. If you make a mistake here it can affect your whole project later. Don't be afraid to tear something down and start over until you get it right.

Look at your work from various angles and imagine the chain in place etc. Is your setup readily adjustable and secure. Solidly mounted components can greatly add to the final safety of the finished vehicle.

This is what the mockup of the ECycle looks llike to this point. Time to run out to the scrap metal dealer to look for some aluminum plate!

Battery placement is a comprimise between available space and safety. Safety should be your priority. The placement of your ECycle's components can affect the weight and balance of your finished motorcycle. Try to position the center of gravity as low as possible, and look for symmetry when placing heavy objects such as batteries. If I had the money I would opt for the more advanced Lithium batteries rather than the laed-acid batteries that were left over from my last project.

I found another section of aluminum plate at the scrap dealer's lot this morning, and have made the rest of the motor mount from it. Using 3/4" square steel tubing as spacer material, I fashioned "cage" to surround the electric motor and to provide the structual rigidity required to properly mount it to the motorcycle frame. The completed assembly is strong and light.

The whole assembly can slide along the main motor mount bolt shaft to provide the correct alignment required by the drive sprockets. When the correct position is determined, steel spacers on either side of this motor mount will be used to prevent any lateral movement of the unit. The completed motor mount "pivots" on the main engine mount bolt. This allows me to raise or lower the center of the motor shaft in relationship to the swing arm pivot point to ensure that the correct chain geometry is set. Again, once the correct position is found, steel links will secure the unit to the rear frame down tubes.

The newly fabricated motor mount will provide physical protection for the electric motor as well. When the final carbon fibre bodywork is constructed it will be designed with several air scoops that will channel a stream of air between these two plates to cool the motor and control electronics.

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Note:
This ECycle conversion project continues on the next few pages. By the Spring of 2006, this solar-powered battery-electric motorcycle will be on the road! Bookmark this web site, and follow along as we create our next EV.