then to a lower force. This occurs because VEX motors have “relax” thermal protection and cut off the current when the motor gets hot. Some motors without thermal protection can be damaged by too much current. The current heats up the motor coils and melts the insulation, coils to each other. Even though VEX motors have overcurrent protection, it is good practice to make this measurement quickly and then turn off the to the motor. It is okay to let the VEX motor cool for ~10 seconds and measure again. d = distance from axis of rotation to point where force is applied = _______ m F┴ = force to stall the motor = ______ N = stall torque = d × F┴ = ______ N·m Record the stall current of the motor. Note that VEX motors will stall at a high current, and then the current will drop, once limited by thermal protection. You want to record the initial, higher value of the current. If a current greater than the range setting of an ammeter passes through the meter, it blows the fuse of the meter and can damage the meter. Always start with ammeter range settings larger than the current could be. VEX motors can draw more than 200 mA, so you are likely to need to use the 10 A setting with the 10 A banana receptacle on the multimeter. Congratulations! You have measured everything you need to measure to characterize your You have all of the most important design parameters that describe the motor’s performance for operation at 3 V. Let’s put them in one place, creating a specification sheet, or spec sheet as it is commonly called. Specification Sheet Motor model: ________ For operation at 3 V: No-load current: ________ Stall current: ________
then “relax” to a lower force. This occurs because VEX motors have thermal protection and cut off the current when the motor gets hot. Some motors without thermal protection can be damaged by too much current. The current heats up the motor coils and melts the insulation, coils to each other. Even though VEX motors have overcurrent protection, it is good practice to make this measurement quickly and then turn off the to the motor. It is okay to let the VEX motor cool for ~10 seconds and measure again. d = distance from axis of rotation to point where force is applied = _______ m F┴ = force to stall the motor = ______ N = stall torque = d × F┴ = ______ N·m Record the stall current of the motor. Note that VEX motors will stall at a high current, and then the current will drop, once limited by thermal protection. You want to record the initial, higher value of the current. If a current greater than the range setting of an ammeter passes through the meter, it blows the fuse of the meter and can damage the meter. Always start with ammeter range settings larger than the current could be. VEX motors can draw more than 200 mA, so you are likely to need to use the 10 A setting with the 10 A banana receptacle on the multimeter. Congratulations! You have measured everything you need to measure to characterize your You have all of the most important design parameters that describe the motor’s performance for operation at 3 V. Let’s put them in one place, creating a specification sheet, or spec sheet as it is commonly called. Specification Sheet Motor model: ________ For operation at 3 V: No-load current: ________ Stall current: ________
1.2.6.A.VEX_MaximizingMotorPower.docx