Objectives:

• Given a simple motor kit, study the model to understand the underlying motor and generator magnetic principles.

Parts List:

• Simple Motor Kit

Introduction

Motors and generators are both considered machines, and both can operate with either ac or dc. This laboratory briefly explores a dc motor. Permanent magnet dc motors (PMDC) are dc motors that have poles consisting of magnets. One primary advantage of these machines is that they do not require a dc field winding, and they have no associated field winding copper losses, as do their dc shunt or induction  motor counterparts. Permanent magnet motors are typically the most efficient motors available. It is only because of the high costs of permanent magnets that more of these motors are not used. The prevailing work horse for generating power to the ac grid is still the ac synchronous generator. A synchronous generator, like its dc counterpart the shunt motor, must have its magnetic field supplied by a separate dc power source.

Prelab.

Build the simple motor kit per the instructions given in the provided link.

Download instructions from http://www.simplemotor.com/kit7.htm.

Procedure A. Simple, Permanent Magnet DC Motor

1. Document any troubleshooting issues you may have encountered in getting the motor to function.

2. Verify that the simple motor rotates, and note how much voltage is needed to turn the motor.

3. Include in your report an oscilloscope screenshot showing the collector to emitter voltage of the BJT.

Make sure to list all supporting details.

What is the applied voltage?

What is the resulting frequency of the waveform?

What is the corresponding rotor shaft speed?

4. Explain in detail how the simple motor works and be sure to include the functions of the reed relay and transistor.

5. Include a photograph in your report of your completed motor.

Questions and Discussion

1. Explain the major differences between a motor and a generator.