motor calculations

Pataasin ang iyong marka sa homework at exams ngayon gamit ang Quizwiz!

If the total resistance of two motor windings connected in parallel is 24Ω and 240V is applied to the circuit is energized

10A

if the total resistance of two motor windings connected in parallel is 20v and 280v is applied to the circuit how much current will flow?

14A

If 480V three phase motor control center feeds a 50Hp motor (65a) a 40hp motor (52a) and a 10hp motor (14a) the minimum feeder ampacity is

161.25A

Synchronous speed of a 60Hz induction motor with four stator poles

1800 rpm

what is the maximum value for a short circuit protection for multi- motor branch circuits

250% of the smallest motor

The synchronous speed of a 60Hz motor with 2 poles is

3,600 rpm

For ordinary motors, the short-circuit/ground-fault protection for noontime-delayed fuses are sized at what percentage of the motor full current?

300%

the maximum recommended size of a dual element,time delay fuse for a 50hp,460v three phase motor rated at 65 fla is

80a

in addition to short circuit protection, MSCPs also serve as a

Disconnecting means

which of the following describes MSCPs?

Fuse-like devices designed for use only in a special type of fusible-switch combinations motor starter

Installation of capacitors on induction motors will

Improve voltage stability

When used for short circuit protection of motor branch circuits, which of the following must be adjustable and used in conjunction with combination motor starters?

Instantaneous trip circuit breakers

Which of the following list full load currents for three phase motors with a known winding type, horsepower, and voltage

Nec 430.250

the requirements for sizing multi-motor branch circuits can be found in

Nec 430.53

The requirements for torque motors shaded-pole motors and AC adjustable-voltage motors can be found in

Nec 430.6

One of the three factors that will cause a three-phase motors magnetic field to rotate is that the

Stator windings around the inside of the motor are arranged in a specific manner to induce rotation

Which of the following is true concerning the starting current of an induction motor at the moment the circuit is energized?

The current rises rapidly

Good electrical protection for a motor includes both proper overload protection and

current-limiting short-circuit protection

In certain motor circuits, one switch can serve as both the controller and the

disconnecting means

the rotating speed of an induction motor is determined by the number of stator poles and the

frequency of the AC line in hertz

To calculate the maximum safe load that a motor may be expected to carry continuously at its rated voltage and frequency, the service factor is multiplied by the

horsepower rating

which of the following is considered to be one of the Nec requires categories of motor protection

overload protection

If a motor has a current draw of 20A at 240V, what will the amperage be if 480V is applied?

10A

Most effective method of power factor correction in the installation of

Capacitors

All motor circuits contain

over current protection


Kaugnay na mga set ng pag-aaral

Micro Economics Practice Final Exam

View Set

Ch 5 Cisco Routing and Switching Essentials

View Set

SCHM Exam 3 - Chapters 9, 6, 11, 14

View Set