1. Steven Jorgensen Chani Martin

2. Motor Characteristics  Stall torque – Maximum Torque output with 0 rotational speed.  Stall Current – Current drawn at stall torque  Free Speed – Fastest Free spin of the motor with 0 load.  Motor Power- Mechanical power motor has.

3. Motor Curve Demonstration  Look and explain F-P Motor Curve here  Show Graphical Representation  Stall Torque  Stall Current  Free Speed  Maximum Power

4. Designing Around Motor Specifications  Calculate Power Requirement  Select Appropriate Motor  Find the Working Torque and Apply Gear Ratio  Calculate Effective(Actual) Gear Ratio  Calculate Effective (Actual) Power Output

5. FRC Problem  Lift a 5lb Ball 7ft in the Air within 6 seconds

6. Step 1: Power Requirement  Power = Torque * Angular Velocity P = Τω = (69N-m)(0.393rad/s) = 27.117 Watts  Arm Parallel to Ground requires most torque

7. Step 2: Select Appropriate Motor  Maximum Available Power for 2010 Motors  CIM (337 Watts at 2655rpm, 172oz-in)  Fisher Price (185 Watts)  Denso (22 Watts)  Mabuchi Motor (30 Watts)

8. Step 3: Working Torque w/ Gear Ratio  Gear Ratios – Transmit Loads at the Gear’s Teeth  F-P Stall Torque = 63.4 oz-in  Design around 20%-50% of stall torque so that gear ratio reflects a torque load on the motor that is near max power.  45% Stall Torque = 28.98oz-in  630 oz-in / 28.98 oz-in =  21.74:1 Gear Ratio  With this Gear Ratio F-P motor only experiences 28.98oz-in of load

9. Step 4: Effective Gear Ratio  Effective Gear Ratio = Motor Power * Total Component Efficiency  Each Gearing Stage Loses 10% Efficiency  Two Stages (7:1 to 4:1)  7*90% * 4 * 90% = 22.68:1 Effective Gear Ratio

10. Step 5: Effective Power  F-P Motor Experiences 28.98 oz-in  Refer to Motor Curve to find Power Output of F-P motor at this torque input.  Power @ 28.98 oz-in Torque = 180 Watts  Effective Power = Motor Power * Efficiency  E.P = Motor Power * (Gear Ratio Efficiency) * (Motor Efficiency)  E.P. = 180 * (0.9*0.9) * (0.5) = 72.9 Watts  Lifting Ball only requires 27.11 Watts

11. Conclusion  Power Requirement  27.11 Watts  Select Appropriate Motor  F-P motor (190 Watts Available)  Working Torque  28.98 oz-in Working Torque. Needs 21.74 GR  Calculate Effective(Actual) Gear Ratio  22.68 G.R. After Efficiency Loss  Calculate Effective (Actual) Power Output  71.9 Watts Available after Efficiency Loss