UNH ECE 791 Senior Project I Design Proposal Presentation

Team Members: Advisor: Luke Vartuli Stephen Doran Doug MacMillan Dr. Gordon Kraft

Problem Statement Problem: Solution: Noise Emissions Cost of operation Electric snowmobile

Project Overview Starting point => Polaris Snowmobile Breakdown of snowmobile Electric motor Motor Theory Motor Control Pulse Width Modulation PWM circuit Power MOSFET’s Mounting bezels Battery type Battery mounting Timeline Budget Contributions

Donor Sled: 1996 Polaris Indy XLT Starting Point Donor Sled: 1996 Polaris Indy XLT

Breakdown of Snowmobile Components Removed: Engine Exhaust Fuel tank Oil tank Starting battery Cooling system

Electric Motor Specifications: Mfg: General Electric Model: 2CM6501 Nameplate Ratings: Voltage: 120VDC Armature Current: 167 A Field Current: 10 A Place of Origin: WWII Era B-29 Aircraft

Armature Main component of the DCMG Uses multiple Armature windings for conduction Undergoes Dynamo effect

Shunt DCMG Armature and Inter-poles are in parallel to the Main poles. As load changes only a fraction of the field will change. Safer, but has bad torque characteristics

Shunt Diagram

Windings

Commutator “Assembly line for current transfer” As the commutator spins, current conducts from the brush (-) to the commutator bars the Load back to the Brush’s(+).

Inter-poles Maintains a neutral field flux over the commutator as the load changes. By having a neutral field flux over the commutator, this limits “sparking” on the commutator which then leads to pitting and damage. This will disrupt proper commutation.

Inter-poles at work!

Motor Control How the motor will be controlled: Vary armature current, fixed field Pulse Width Modulation (PWM) Power MOSFET’s

Pulse Width Modulation (PWM) Use PWM to control armature, fixed field PWM controls power MOSFET’s As duty-cycle increases, switches on longer, motor spins faster

PWM circuit

Power MOSFET’s Pros: High current Fast switching Low resistance Cons: No protection from fly back voltage Get hot

Mounting Bezels Key Components: Bed plate Motor Motor bezel Bearing Bezel Clutch assembly Orig. Motor Mounts

Battery Type Flooded Lead Acid, Why? Availability Low cost Ease of configuration Ease of mounting Ease of connection Source: www.carbasics.co.uk/inside_car_battery.gif

Battery Mounting Configuration: Series Nom. Voltage: 120VDC Mounting: Battery rack with top straps

Timeline

Budget Snowmobile: Donated Electric Motor: Donated Wire and misc. supplies: Donated Mounting Bezel: $200 Batteries: $1000 Pulse Width Modulator: $150

Contributions Donations: Support and Guidance: Snowmobile donated by Vincent Pelliccia DC Motor donated by Kevin White Wire and misc. electrical materials donated by Vartuli Electric, LLC Support and Guidance: Prof. Kraft Prof. Hludik Prof. Clark Prof. Smith Adam Perkins Matt Borowski

Thank you for your time

DC MOTOR THEORY Same concept as AC Motor/Generators Utilizes carbon brushes for DC characteristics

Flemings right Hand rule

Armature Physics

Commutation Diagram

Compound DCMG Utilizes both series and shunt characteristics More common DCMG

Compund Diagram

Series DCMG Poles, Inter-poles, and Armature all in series. Change in load is directly proportional to change in speed. Reduction in load can cause a “run-away” motor which will then lead to mechanical failure. High torque applications.

Series DCMG diagram