Current (DC) motors.

DOE-STD-1170-2003

Describe the differences in construction between a shunt-wound and a

series-wound direct current generator with respect to the relationship between the

field and the armature.

Describe the relationship between the shunt and series fields for

cumulatively-compounded and differentially-compounded direct current

generators.

Describe the voltage-versus-current characteristics for a flat-compounded, over-

compounded, and under-compounded direct current generator.

Electrical systems personnel shall have a working level knowledge of direct

current (DC) motors.

Supporting Knowledge and/or Skills

Describe the basic construction and operation of the following four types of direct

current motors:

Shunt

Separately excited

Compound-wound

Series

State the function of torque in a direct current motor and how it is developed.

Describe the function of counter-electromotive force (CEMF) and how it is

developed in a direct current motor.

Describe the relationship between field current and magnetic field size in a direct

current motor.

Describe how to adjust the speed of a direct current motor.

Describe the relationship between armature current and torque produced in a

direct current motor.

Describe the torque-versus-speed characteristics for a shunt-wound and a

series-wound direct current motor.

Explain why starting resistors may be necessary for large direct current motors.

Electrical systems personnel shall demonstrate a working level knowledge of

battery construction, voltage production, and hazards.

Supporting Knowledge and/or Skills

Using a cutaway drawing of a simple multi-cell storage battery, identify the

following components and discuss their function:

Positive terminal

Negative terminal