Engineering Basic calcs in excel for dc lap wound motor

[el_diablo549]

Homework Statement

My group and I have to design a lap wound dc motor. Maximum of 12 volts and 5 amps. Must have no more than two poles. The aim is to achieve maximum efficiency. I've created this excel spread sheet to calculate the gauge of wire we need and the type of magnets. Also how many turns per a coil we need and What voltage and amperage to set it to to achieve maximum efficiency. I understand the amperage is based of a load but the motor will be connected to a mini type of dyno to apply a set load.

Homework Equations

Too many to list I've tried to write the equation next to each cell or explain it how ever some have been changed and I've lost track of them. Also I understand that our efficiency is based off no load speed and full load torque which is two very different scenarios but we are just using it as a basis for our calcs.

The Attempt at a Solution

I realize there is so much more to calculating the properties of a dc motor however This is a mechanical engineering course so we are just concentrating on the biggest factors so to speak. The current selection for wire gauge and magnet type is what my group has opted for we just want to make sure we are in the ball park figure for achieving a decent efficiency for our settings as we have a financial interest in this.

 

[el_diablo549]

Also we have noticed a lot of commercial motors are wrapped on angles, were not sure what or how to work out the angle required I assume it helps the motor initially turn which is one of our criteria that the motor turns without assistance at the start. Sorry if I've missed anything we are just really flustered at the last minute and want to make sure were not on totally wrong path and wasting our time. Thanks in advance