Before testing insulation with a meg ohmmeter, the windings of large machines should be grounded for about 15 minutes just prior to test, because the
A reverse current relay prevents dc generator motorization automatically by option
The electrician reports to you that he has obtained low (but above 1 megohm) megger readings on the windings of a deck winch motor. Upon checking the records of that motor, you find the readings have consistently been at the same level the last six years. You should, therefore, recommend that the
Di electric constant of 3.6
The most common source of excitation for synchronous motors is a/an _____________.
On an engine throttle control system, the aux control circuits are provided with devices to prevent excessive over travel of the pilot valve by the synchronous motor these devices are called.
How is natural cooling of transformer done?
In testing a three-phase delta winding for an open circuit using a meg ohmmeter, you must
The direction of rotation of an induction motor is
The function of the compensating windings used in a DC generator is to
Most conductive materials such as copper, aluminum, iron, nickel
The purpose of a main switchboard circuit breaker's revers-power trip is to
The purpose of a motor under voltage protection device is to
To satisfy amplification, transistor amplifier must satisfy?
How with the help of pressure electrical signal is converted? i. Transducer ii. Tuctile sensor iii. Reactor iv. Don’t remember
Regarding an induction motor, the power developed by the rotor automatically adjusts itself to
In a DC series circuit, all the conductors have the same
A grounded switch or cable will be indicated by a meg ohmmeter reading of
Capacitors are used on the output of the power supply in today's consoles to
Across-the-line starters are used with AC motors to provide
Electric and electro-hydraulic steering gear motors are required by Coast Guard Regulations (46 CFR) to be _________.
For half wave rectifier ripple factor is? (for full wave- 0.482)
To prevent the race of DC series, motor what arrangement should make?
The speed of the squirrel cage induction motor is determined by
Which statement is not true in relation to AUTO TRANSFORMER? (mcq)
Most three-phase induction motors used for driving engine room auxiliaries are started by
What happens to the strength of electromagnetic field when current passing through an inductor is halfed?
The main difference between an electron tube and a transistor is the
If thyristor is used in place of starter (mcq)
mercury filled thermometers should never be used to determine the temperature of the battery electrolyte because accidental breakage of the thermometer can cause
When electrical cables penetrate watertight bulkheads
Pure inductive power is called
Class B AMPLIFIER advantage?
For a turbo electric propulsion generator which can be fitted?
When charging lead-acid batteries, the charging rate should be reduced as the battery nears its full charge to
If in an electromagnetic coil current is ½ then its energy stored will be?
RMS value of a sine wave current is expressed as
For incoming generator which of the statements are true?
The method used to produce electron emission in most vacuum tubes is known as
A three-phase induction-type motor experiences an open in one phase. Which of the listed automatic protective devices will prevent the machine from being damaged?
The purpose of a magnetic relay is to
A semiconductor is a material with a
Line losses in a distribution circuit are kept to a minimum by
Which of the following statements comparing transistors and vacuum tubes is correct?
Regarding battery charging rooms, ventilation should be provided
The winding resistance of a coil can be increased by _______ the number of turns or using a ______ wire.
Adding resistance in series with the field winding of a DC shunt motor without a load, will cause the motor speed to
Which of the following devices will prevent a DC generator from becoming motorized?