In terms of speed control, how does a four-terminal starter differ from a three-terminal starter?

What will be an ideal response?


A four-terminal starter provides for variable speed control using a field rheostat. As the arm is raised to the first position, the shunt field receives full voltage, yet there is still resistance in the armature circuit. As the arm is moved to the right, resistance is added to the shunt field circuit but removed from the armature circuit. Because adding resistance to the shunt field circuit reduces the current to the field, the holding electromagnet is not in series with the shunt field but is connected across the line, hence the fourth terminal.

Trades & Technology

You might also like to view...

Which of the following fuel sub-system components is NOT under suction in a V-MAC III EUP fuel system?

A. fuel tank B. primary filter C. ECU D. secondary filter

Trades & Technology

? Identify and state the historical significance of the Branch Davidians.

What will be an ideal response?

Trades & Technology

Identify the primary standard published by the American Society of Mechanical Engineers (ASME) that establishes uniform practices for stating and interpreting dimensioning, tolerancing, and related requirements for use on engineering drawings and related documents.

What will be an ideal response?

Trades & Technology

When charging a machine's battery this is the best advice:

a. high and hard b. long and low c. soft and low d. fast and short

Trades & Technology