41-50 Definitions

Question 1

Field Circuit Breaker, Contactor or Switch

Answer 1

A device which functions to apply and/or remove the machine field excitation

Question 2

Running Circuit Breaker, Contactor or Switch

Answer 2

A device whose principal function is to connect a machine to its source of running voltage

Question 3

Transfer Device

Answer 3

A manually operated device which transfers the control circuits to modify the plan of operation of the switching equipment

Question 4

Unit Sequence Starting Contactor or Relay

Answer 4

Functions to start the next available unit in a multiple-unit equipment on failure of non-availability of normally preceding unit

Question 5

DC Overvoltage Relay

Answer 5

Functions on a given value of DC circuit over-voltage

Question 6

Reverse-Phase, Phase-Balance Current or Power Rectifire Misfire Relay

Answer 6

Functions on polyphase current of reverse-phase sequence, or on polyphase current unbalance, or on failure of one or more of the power rectifier anodes to fire

Question 7

Single or Reverse Phase Voltage Relay

Answer 7

Functions upon a given value of polyphase voltage of the desired phase sequence

Question 8

Incomplete Sequence Relay

Answer 8

One which returns the equipment to the normal, or off position and locks it out if the normal starting, operating or stopping sequence is not properly completed within a predetermined time

Question 9

AC Thermal Relay of Device

Answer 9

Functions when the temperature of the AC machine or apparatus exceeds a given value

Question 10

Short-Circuit Selective Relay or Device

Answer 10

Functions instantaneously on an excessive value of current, or an excessive rate of current rise, indicating a fault in the apparatus of circuit being protected