Evaluating DC Motors

Determining Motor Stall Torque and

No Load RPM

The Test Bench Set UpRequirements

Securely fasten motor to the Test Bench.

Use #10 AWG or larger, Multi Stranded Wire.

Battery or Batteries similar to those intended for use in the BattleBot.

HD Automotive Starter Switch

Caution: Testing motor torque creates strong electrical and mechanical forces. Wear Eye Protection. Work with Adult supervision.

Build a motor torque arm

Special Equipment

Use 1”x1”x1/16” steel angle

3/8” Shaft Collar

Create the Stall Condition

3 People should perform the test.

Set up and hold the scale

Mark the scale

Energize/de-energize the system.

Wear Eye Protection

Set Up and Hold the ScaleWear Eye Protection

Motor

Torque Arm

Scale with Taped Marking

Torque Arm Retainer

Create the Stall Condition

ProcedureWear Eye Protection

Assume the stations; EnergizerScale holderScale marker

Energize the SystemRaise the Torque Arm with the ScaleMark the Scale DeflectionDe-Energize.

ALWAYS Record, Describe and Date the Data

Determining the Torque Value

ALWAYS Record, Describe and Date the Data

DF

F = Force (lbs.) 3 lbs

D = Length (ft.) .5 ft

Q = Torque (ft.lbs.)

Q = D x F

1.5 ft.lbs. = .5 ft. x 3 lbs.

Measure No Load RPM

ProcedureWear Eye Protection

Mark Armature Shaft with Reflective Tape.

Energize the System

Read the No Load RPM

De-Energize.

ALWAYS Record, Describe and Date the Data

Directly Measuring Motor Stall Torque is a Learning Experience.

Ammeter

VoltmeterSample Motor

NC MO Switch

12V Battery