## Induction machine operation, Mechanical Engineering

Assignment Help:

Induction Machine Operation

For operation with rated L-L voltage of 230 V and rated frequency of 60 Hz, the performance of a particular 10 hp machine at its rated speed and power is:

Speed = 1750 rpm I1 = 24.5 A rms Pin = 7.93 Kw T = 40.7 Nm Pout = 7.46 Kw

S = 0.0277 Cos è = 0.811 Pg = 7.67 Kw I2

2R2 = 212w eff = 94.1 %

a) One important parameter change for efficiency improvement is to reduce the value of R2. Determine the new values of the quantities above for a second identical machine except that R2 is 1/2 as large and the machine is operated at 1/2 the slip (so R2/S = constant). This is a "thinking question", the answers can be obtained with only minimal calculation (many are unchanged) by reasoning guided by the equivalent circuit. Don't make it hard or long.

R2new = (1/2) R2

Slip = __0.01385___ Po = ___________ hp

Speed = ______ RPM cos è = _________

I1 = ___________ A Pg = ___________ w

Pin = ___________ w I2R2 = _________ w

T = ___________ Nm eff = ___________ %

b) The equivalent circuit parameters of the above10 hp, 230 V (rms L-L), 60 hz, 4 pole, three phase induction motor are:

r1 = 0.140Ù x1 =0.650Ù xm = 12.0Ù

r2 = 0.157Ù x2 = 0.650Ù Neglect core loss

Use the equivalent circuit to find the input current and developed torque at rated voltage and frequency and a slip of S = 0.01385 (1/2 rated slip). As a first approximation I1 and T were shown to be linear functions of slip. Compare your results with 50% of the rated slip values as listed below.

Equiv Ckt @ S= 0.5 SR 50% of Rated Values

I1 = _________ A I1 = __12.25__ A

T = _________ Nm T = ___20.35__ Nm

Induction Machine Operation

c) Evaluate the motor performance at 15 hz with constant volts/hz and at the same slip frequency as in part a (S = 4 x 0.0277 = 0.1108) neglecting R1). Recall that, without stator resistance, the current, torque and power factor are the same as the rated values given in part a, only the powers vary.

Optional: Include R1 This requires an equivalent circuit calculation.

R1 = 0 (25 points) R1 ≠ 0

I1 = ___________ A I1 = ___________ A

Pin = ___________ w Pin = ___________ w

T = ___________ Nm T = ___________ Nm

Po = ___________ hp Po = ___________ hp

cos è = _________ cos è = _________

Pg = ___________ w Pg = ___________ w

I2R2 = _________ w I2R2 = _________ w

d) Test s show the starting current and torque of a (different than in part a) motor to be

I = 6 x IR A T = 1.5 x TR Nm at rated voltage V = VR

Use this starting performance data to find the voltage ratio (Vo/Vin )of a transformer which when placed between the motor and the source Vin = VR will limit the transformer input side starting current to = 2 x IR A.

What is the torque and motor side current as multiples of rated values of when using this motor starting transformer? Hint: At starting, (S = 1) the motor is simply an impedance. (25 points)

Vo/VR = _________

I1 = ______ x IR

T = ______ x TR

#### Soil conditions for plant layout, Q. Soil conditions for plant layout? ...

Q. Soil conditions for plant layout? Soil conditions affect the foundation requirements, drainage, type of substructure used and may limit the size and shape of the facility. T

#### Classification of force - mechanics, Classification of force: Single f...

Classification of force: Single force is of two types that is, Tensile and compressive. Generally in a body several forces are acting. When a number of forces of different mag

#### What is data unification, What is Data Unification To optimize the UPR ...

What is Data Unification To optimize the UPR data structures, during design we study the semantics of each data type of the supported CAD systems and identify data types that a

#### Elements of cad, Human Factor : The human factor is the key factor in th...

Human Factor : The human factor is the key factor in the success of CAD system. This concerns the training of the designer or the engineer without whom the CAD system become

#### Instantaneous center method, Linear velocity of links using Instantaneous c...

Linear velocity of links using Instantaneous center method

#### Describe about push-pull welds, Q Describe about Push-pull welds? - A ...

Q Describe about Push-pull welds? - A push-pull system employs transformers with an electrically reversed polarity arrangement wherein two transformers complement each o

#### Essay, which topics i should take from mechanical engineering to compare th...

which topics i should take from mechanical engineering to compare them

#### What is two way punching shear, What is Two Way Punching Shear? Two Way...

What is Two Way Punching Shear? Two Way Punching Shear In columns, generally the tendency of the column is to punch through the footing.  This also is to be considered in de

#### Design analysis drafting machine, hello,my name is mustapha from iran I wa...

hello,my name is mustapha from iran I want design piston engine (structure design cranckshaft ,rod,bearing,...)

#### Objectives-object-oriented control architecture , Objectives After stud...

Objectives After studying this section, you should be capable to understand: Cell control and modeling, Context level data flow diagram, A common cell control sy

### Write Your Message!  #### Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd