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2 years ago

A 60-Hz 3-phase induction motor is required to drive a load at approximately 850 rpm. How many poles should the motor have

Engineering

1 answer:

Anastaziya [24]2 years ago

7 0

Answer:

8 poles

Explanation:

Given

$Frequency, f = 60Hz$

$Speed, n_s = 850rpm$

Required

Calculate the number of poles the motor should have?

To solve this question, we make use of synchronous angular velocity formula

$n_s = \frac{120f}{P}$

Where

$P = Number\ of\ Poles$

Substitute values for $n_s$ and f in $n_s = \frac{120f}{P}$

$850 = \frac{120 * 60}{P}$

$850 = \frac{7200}{P}$

Multiply both sides by P

$P * 850 = \frac{7200}{P} * P$

$P * 850 = 7200$

Divide both sides by 850

$\frac{P * 850}{850} = \frac{7200}{850}$

$P = \frac{7200}{850}$

$P = 8.47058823529$

However, the number of poles must be an integer.

So:

$P = 8$

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An approach to a signalized intersection has a saturation flow rate of 1800 veh/h. At the beginning of an effective red, there a

Tcecarenko [31]

Answer: The total vehicle delay is

39sec/veh

Explanation: we shall define only the values that are important to this question, so that the solution will be very clear for your understanding.

Effective red time (r) = 25sec

Arrival rate (A) = 900veh/h = 0.25veh/sec

Departure rate (D) = 1800veh/h = 0.5veh/sec

STEP1: FIND THE TRAFFIC INTENSITY (p)

p = A ÷ D

p = 0.25 ÷ 0.5 = 0.5

STEP 2: FIND THE TOTAL VEHICLE DELAY AFTER ONE CYCLE

The total vehicle delay is how long it will take a vehicle to wait on the queue, before passing.

Dt = (A × r^2) ÷ 2(1 - p)

Dt = (0.25 × 25^2) ÷ 2(1 - 0.5)

Dt = 156.25 ÷ 4 = 39.0625

Therefore the total vehicle delay after one cycle is;

Dt = 39

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3 years ago

All brake lights are dimmer than normal. Technician A says that bad bulbs could be the cause. Technician B says that high resist

yarga [219]

Answer:

All Brake lights are dimmer than normal because high resistance in the brake switch could be the cause according to Technician B.

Explanation:

According to Technician A

When the bulb is faulty then no current will flow through bulb and it will be open circuit.So no light will produce in bulb .

According to Technician B

When a high resistance inserted in series circuit the voltage across each resistance is reduced and this cause the light glow dimly.

Formula of resistance in series circuit

Rt=r1+r2+r3......

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3 years ago

Lagest organs of the human body

aliya0001 [1]

Answer:

skin is the largest organ

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2 years ago

Read 2 more answers

Two particles have a mass of 7.8 kg and 11.4 kg , respectively. A. If they are 800 mm apart, determine the force of gravity acti

aleksley [76]

Answer:

A) About $9.273 \times 10^{-9}$ newtons

B) 76.518 newtons

C) 111.834 newtons

Explanation:

A) $F_g=\dfrac{GM_1M_2}{r^2}$ , where G is the universal gravitational constant, M 1 and 2 are the masses of both objects in kilograms, and r is the radius in meters. Plugging in the given numbers, you get:

$F_g=\dfrac{(6.67408 \times 10^{-11})(7.8)(11.4)}{(0.8)^2}\approx 9.273 \times 10^{-9}$

B) You can find the weight of each object on Earth because you know the approximate acceleration due to gravity is 9.81m/s^2. Multiplying this by the mass of each object, you get a weight for the first particle of 76.518 newtons.

C) You can do a similar thing to the previous particle and find that its weight is 11.4*9.81=111.834 newtons.

Hope this helps!

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3 years ago

cThe Mars Rover Spirit got stuck in the Martian sand. The wheels kept slipping. Attempts to free it were futile. Discuss the typ

IgorC [24]

Answer:

Improved/ advanced types of Actuators include servo systems, create a large range of actuator motion in response to the changing needs of the operational environment or process.

Actuators are local or automated suppliers of working motion.

Hydraulic and air cylinders can be classified as single-acting cylinders, meaning that the energy source result in movement in one direction and a spring is used for the other direction.

Explanation:

An actuator control system is referred to as any electronic, electrical, or electromechanical system often used to activate an actuator, control the direction as well as extent and duration of its output. Actuator control systems could take the form of extremely simple, manually-operated, start-and-stop stations, either sophisticated or programmable computer systems. The more improved/ advanced types include servo systems that produce a large range of actuator motion in response to the changing needs of the operational environment or process. This type of actuator control system uses an interface arrangement that assimilates feedback from the process or mechanism and adjusts the actuator in the right way. Most actuator systems will include at least a set of travel limits that prevent the actuator destroying itself or the secondary mechanism.

Actuators are local or automated suppliers of working motion. They are used to changes, adjust, or move a secondary mechanism, where a physical operator cannot intervene directly. They are denoted by a large range of varying types using electrical and electromagnetic, hydraulic, or pneumatic power sources to create linear or rotary outputs. One element they all have in common is the actuator control system used to start, stop, and adjust the range, speed, and duration of the working motion.

Actuators can produce a linear motion, rotary motion or oscillatory motion which means they can create motion in one direction, in a circular motion or in opposite directions at regular intervals. Hydraulic and air cylinders can be classified as single-acting cylinders, meaning that the energy source result in movement in one direction and a spring is used for the other direction.

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3 years ago