- •V.S. Martynjuk, I.I. Popovska
- •Study of the electromechanics energy converters design Aim of work
- •Theoretical positions
- •Design of direct current electromechanics converters
- •Design of synchronous electromechanic converters
- •Designs of asynchronous electromechanics converters
- •Order of work performance
- •Contents of a report
- •Control questions
- •Research of single-phase transformer Aim of work
- •Order of work implementation
- •Table of report contents
- •Control questions
- •Research of dc generator of parallel excitation Aim of work
- •Order of work implementation
- •Control questions
- •Research of direct current мотоrs Aim of work
- •Report content
- •Control questions
- •Research of three-phase asynchronous motor with squirrel-cage rotor Aim of work
- •Order of work performance
- •Table of report contents
- •Control questions
- •Calculation of electromagnets of direct-current а. Preliminary calculation of electromagnet. Calculation of key size of core
- •1.1. Electromagnets with external turning armature
- •B) Recursive short-time mode
- •C) Short-time duty
- •1.2. Electromagnets with external forward armature travel
- •B) Recursive short-time mode
- •C) Short-time duty
- •Design of asynchronous machines
- •Features of asynchronous generators operation
- •2. Determination of main sizes and calculation of asynchronous machine
- •Choice of number of stator and rotor slots
- •4. Active and inductive resistances of stator and rotor winding
- •5. Choice of excitation capacitor
- •6. A calculation of magnetic circuit and determination of o.C. Current of asynchronous machine in traction mode
- •7. Calculation and plotting of magnetic characteristic (b-h curve) of asynchronous machine
- •8. Plotting of operating characteristics of asynchronous motor
- •9. Losses of energy and efficiency of asynchronous machine
- •Home work (by discipline “Aviation electric machines and devices”)
Order of work implementation
To familiarize with the design of the investigated transformer and equipment of the laboratory setting. To write down technical data of measuring devices to protocol.
To assemble a plant for research of transformer by a chart, represented on fig. 1.8.
2. To research open circuit mode; it is needed for this purpose
to turn off by the switch S1 a load resistance ZL. Setting by means of autotransformer the least of possible voltages, to plug a transformer in a network. Fluently increasing voltage, to take off the readings of devices at the next values of voltage:
0,25U1nom; 0,5U1nom; 0,75U1nom; U1nom; 1,2U1nom.
Fig. 1.8
To bring the results of measuring and calculation data to the table. 1.1
Table 1. 1
Measuring |
Calculation |
||||||||
U1, V |
I0 А |
U20 V |
P0 W |
cosφ0 |
k |
Zm, Ω |
Xm, Ω |
Rm Ω |
I0/I1nom |
|
|
|
|
|
|
|
|
|
|
3. To research experience of short circuit, for what it is needed at the switched off transformer to include in a chart (fig. 1.8) ammeters with the limit of measuring, which equals to 1,5∙Inom. To change the limit of measuring to the wattmeter to the necessary limits. To short out secondary winding, closing switches S1 and S2. Before powering on the transformer to reduce source voltage up to the zero.
Plugging a transformer in a network, increasing the supply voltage consistently to set the following values of current: 0,1Inom; 0,25Inom; 0,5Inom; 0,75Inom; Inom;1,2Inom.
To bring the results of measuring and calculations to the table. 1.2
4. To research transformer in an operating duty at the active, inductive and capacitive load.
At dead source of feed to connect active load resistance to transformer. For this purpose to close the switch S1 and turn off S2 (fig. 1.8).
Table 1.2
Measuring |
Calculation |
||||||||
U1, V |
I1, А |
P1 W |
I2 А |
kL = I1 / I1nom |
U1 = U1/U1nom |
cosφk |
Rk,Ω |
Zk Ω |
Xk Ω |
|
|
|
|
|
|
|
|
|
|
Before powering on the transformer its voltage must be minimum possible, and load resistance − maximal.
To increase the supply voltage up to the rated value U1 = U1nom. Diminishing resistance of load, consistently to set the next values of current І2 : 0; 0,25I2nom; 0,5I2nom; 0,75I2nom; I2nom;1,2I2nom. Primary voltage here to support nominal U1nom.
Like to research transformer at inductive and capacitive character of load.
To bring the results of measuring and calculations to the table. 1.3.
Table 1.3
Measuring |
Calculation |
|||||||
I1, A |
P1, W |
U2. V |
I2, A |
cosφ2 |
kL = I1 / I1nom |
P2, W |
η, % |
ΔU |
|
|
|
|
|
|
|
|
|