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Old 10-09-2012, 10:31 PM   #18 (permalink)
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A revision to the scope

Originally Posted by TeamWIKISPEED View Post
A couple of small decisions:
- the DC version will start with 5 batteries, the largest of the deep cycle cells that weigh about 70 lbs each
- the batteries will be bolted to a ladder frame, and the frame will be bolted into the motor module
- the batteries are one level high, taking up only 10 inches of the 18 inches of available height
- the DC controller, the battery charger, and a junction box containing the fuses, contactor, shunt and a disconnect will be mounted above the motor and transmission. This will take up the room above the motor and transmission and make the controller, junction box, and charger accessible while the module is in the car.
- the controller, charger and junction box are mounted on a ladder frame, which is bolted to the motor module as a separate sub-module

- the AC version will start with 8 sets of 5 batteries each. These are recycled surplus 7 A-h UPS batteries (gel-cells). They will be connected in 4 series, 2 parallel (20 cells in series, 2 strings in parallel)
- the battery packs are stacked 2 wide, 2 deep and connect to a central rack that uses the connectors built into the cases
- the AC controller, the battery charger, and the junction box described above will be mounted above the motor and transmission.
- the controller, charger and junction box are mounted on a ladder frame, which is bolted to the motor module as a separate sub-module
There has been very little progress in the past few weeks. This scope change is an attempt to get around some of the blocks.

A couple of iterations have been done on the preliminary design. It
should allow for more modular changes. I tried putting the excel
'sketch' inline and it does not show well so it is attached.

The sketch shows a top view, an end view and a side view of the
module. The end view shows the back of the module as it sits in the
car. Batteries take up the 'front' half - this is a change from above.
The motor and transmission
take up the 'back' half on the bottom. Above the motor and
transmission are the Charger, Big Junction Box, and Controller (Left
to Right). My labeling is OK once you know where things are. No
interfaces are shown (mechanical linkages, physical wiring, etc)

Based on this modular design, the Battery Charger, the Battery Packs,
the Electric Motor and the Motor controller are all supplied by the
builder of the car - the user. The unit that ties all of these parts
together and makes it into an Electric Motor Module is a Big Junction
Box, or BJB. This is where present design time is being spent.

The idea is that each of these parts - motor, battery pack, charger -
is connected to the BJB in the middle. All wires go through the BJB.
That's the basis of the modularity - each component has only 1
interface to deal with so it can be iterated or replaced with a
functional equivalent with no changes to the rest of the design. To
do that, the interface between each component and the junction box
needs to be detailed. Some room will be reserved for optional
interfaces to be added (the junction box will not be full) - like an
analog brake signal for regenerative braking, not required but there
will be terminal blocks and pins reserved in the connectors.

The BJB contains an assortment of electrical parts that tie the
components together. This includes contactors, fuses, test points,
terminal blocks, switches, a shunt, and a lot of insulated covers.
More details will be posted as they are worked out, including a connector
to the 'rest' of the car.
Attached Files
File Type: pdf WIKISPEED Electric Motor Module.pdf (19.2 KB, 61 views)
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