Considering all the above points number of slots per pole phase for salient pole machines may be taken as 3 to 4 and for turbo alternators it may be selected as much higher of the order of 7 to 9 slots per pole per phase In case of fractional slot windings number of slots per pole per phase may be selected as fraction 3.5. Design engineers must account for every component that will occupy the limited space of a stator slot. of conductor per slot, Mica or bituminous layers to separate the insulated conductors. The slot loading should not exceed 500 Ampere conductors. leads to custom motor designs where the emphasis is on performance over cost and manufacturability; as production volumes increase, cost and manufacturability generally become more important. The motor has a full-load efficiency of 85% and a full-load power factor of 0.8. Your question is solved by a Subject Matter Expert. A 50kW,3 -phase, 60 Hz,3 pole pair induction machine with 72 stator slots is assumed in this project. The revised design held the same amount of copper fill and made the stator manufacturable without changing the winding. (vii)Full transposition of the strands of the single turn coils are required to eliminate the eddy current loss. Above 80 percent is very difficult; inserting all the components without damaging the wire or its insulation requires custom tools and fixtures, and may take up to three times as long or longer to manufacture than lower slot fill designs. Assume suitable values for the missing design data. As mentioned above, a slot opening must allow wire to pass through during insertion and accommodate some manufacturing aids that protect the wire from the edges of the steel teeth, especially when slot liners are the primary means of insulation. However such slots will lead to higher air gap, contraction factor and hence poor power factor. Stator of an induction motor consists of stator core and stator slots. If, even in this case, a solution is not found, rectangular cross-sectional magnetic wire is used. Advantages of higher value of current density: (i)reduction in cross section, Disadvantages of higher value of current density, (i)increase in resistance, (iii)increase in temperature rise. Power =(2pispeedTorque)/60, A:GivendataP=460hPV=415VPoles=4F=50Hzovervoltage=480VStatorconductorlosses=12.6KWRotor, Q:1. As we do have a permanent capacitor motor, the auxiliary winding is always operational. iii. Outer Diameter - 520.5 mm; Inner Diameter - 330 mm; Shaft Bore - 105 mm; . This variation is difficult to anticipate in the design phase. Depth of the stator core can be calculated as follows. Rotor Parameters (c) the turns per phase The electrical angle between emfs in neighboring slots aec is. Practical experience from winding two cable wound generators is used to propose optimized dimensions of different parts in the stator slot geometry. Q=335hpV=2000VP=6f=60Hzr1=0.2r2'=0.203re=450x1=0.707x2=0.707x=77, Q:11. But looking into the advantages and disadvantages of higher number of slots, suitable number of slots per pole per phase is selected. The dimensions of the machine's stator slots are shown in Figure 1 with all . As the stator tooth is tapering towards the bottom, the flux density is calculated at 1/3rdheight from the narrow end of the tooth. 3. When slots are intended to be used for holding only, tolerances can be 0.0 + 0.010 inch or H12 Metric (ISO/R286); when intended for location, tolerance can be 0.0 + 0.001 inch or H8 Metric. Terms and Conditions, Study Material, Lecturing Notes, Assignment, Reference, Wiki description explanation, brief detail, Design of Electrical Machines : Synchronous Machines : Design of stator winding - Design of Synchronous Machines |, Design of stator winding - Design of Synchronous Machines. Normally the width of the strands is assumed between 4 mm to 7 mm. Hence width of the tooth may be estimated corresponding to the permissible flux density at the middle section of the tooth. a) Generator armature current (Ia =?) We are authorized to answer, Q:A three phase, 50 Hz, 4800V, 6 pole Y-connected synchronous generator connected to an 1.5A 10pole, 380 V, 50 Hz, Dconnected threephase induction motor is rotating a quarry belt conveyor. The filter media As already discussed in Chapter 4, when dealing with design principles of three-phase IMs, there are basically two design initiation constants, based on past experience: The machine utilization factor CU:D^L The rotor tangential stress f, in N/cm2 or N/m2. However, if Fmtr 1.3 mm, in low-power IMs, we may use a few conductors in parallel ap. Thickness of coil separator is 0.5 mm to 0.7 mm for low voltage machines and 0.8 mm to 1.2 mm for high voltage machines. Download scientific diagram | Stator slot dimensions. This size range provides a good copper to insulation ratio, is durable and easily formed, and is small enough to be readily worked. Consequently, the stator tooth mmf Frals is. Becausestatorsare cylindrical, the slots are shaped like wedges. You shouldn't let yourself be blind to signals of change nor should your staff believe that you are not in the loop on these issues. Single or double layer windings may be used depending on the requirement. Some of the greatest challenges for a custom stator manufacturer are related to maximizing the amount of copper wire inserted into each slot (commonly referred to as slot fill) to maximize torque output. R2 = 0.0.3 Beyond the physical design limits and the question of how much slot fill is appropriate for the application, engineers have to account for manufacturability. Corners of T-Slots may be square or may be rounded or broken to the indicated maximum dimensions at the manufacturer's . If applicable, that estimated coil area is then multiplied by the number of coils per slot. Each slot of the stator conductor consists of two stranded conductors as shown in. It is given that: Assume, Average gap density=0.4 Wb/m2, ampere conductors per metre = 25,000 A/m, Efficiency = 90%, Power factor = 0.9 and winding factor = 0.96. We have already calculated the area of cross section of the conductor. The, Q:A 4 pole DC shunt generator with wave One manufacturer had a calculated fill factor of about 93 percent in a design with a flat bottom slot shape. The motors torque output is determined by the voltage applied to the wire, the density of the wire, the number of coils, and the number of coil windings. Standard bare size of round and rectangular conductors can be selected by referring the tables of conductors given in Design data Hand book. If the armature, A:The circuit diagram of DC shunt generator is shown below: 2/3 x pole pitch/( slot pitch at top section) Slot width = slot pitch at the top section tooth width at the top section. 6 D c c-----1 2, 4, 6 4, 6, 8 The outer diameter of the stator core (as a preliminary) D D a (2.23) Large segment of the chord 1 Z Z D H c a c (2.24) The number of turns per phase 1 1 1 1 a p u q w s (2.25) 10. XM = 42.2 Depth of stator core below the slots:There will be certain solid portion below the slots in thestator which is called the depth of the stator core. When the dimensions of the stator slot change, the closed-loop regulation of the control system ensures that the operating conditions of the motor are kept constant. Figure 13 shows the coils placed in slots. Iron and shunt losses are 468.75 W. However in case of turbo alternators variation of flux density along the depth of the slot is appreciable and hence the width of the tooth may be estimated corresponding to the flux density at the top section of the tooth or the width of the tooth at the air gap. Nr=1447 rpm, X1=X2'=2, r2'=0.4,. Three-phase induction motor, 460 V 50 Hz, 4 poles, 50 hp with Delta, operating at 3.8% slip rated torque when receives Line Voltage 460 V, 50 Hz The parameters of the equivalent circuit per phase are as follows.R1 = 0.33, X1 = X2 = 0.42 and Xm = 30 Ohm / phase.Answer the following questions by neglecting the mechanical losses, Core losses and Stray load losses.A) Value of the rotor resistance R2B) Maximum torque and rated speedC) line current and starting torque of motor. For example, a part with an aspect ratio of about 3.25 will be more difficult to build than one with the same OD but a ratio of 2.5 because of the effort required for insertion. In practical terms, 100% slot fill would theoretically result in the maximum possible output torque of the motor, but such a design would be impossible to build. Do= D + 2hss= 2 dcswhere hssis the height of the stator slot. The size and number of slots determine how much wire can be contained in each coil, and the wire diameter determines the amount of current that can pass through the coil. First week only $4.99! Practice bears this out. Generally full pitched double layer windings are employed for stator windings. 1.5.2Estimate the Output torque of the motor under the rated conditions. The dimensions of individual strands are selected based on electrical considerations and the manufacturing requirements. 30 most popular quick connects adapters. Two relatively coil designs allow engineers to break down coil size without changing the number of parallel wires or turns in the coil. Stacks are made of individual laminations which vary from one to the next depending how they were manufactured. Khn ~ 0.35-0.4 below lOkW and 0.4 to 0.44 above lOkW. Slot space factor = Copper area in the slot /Area of each slot . Consequently, the whole design procedure has to be brought back to Equation (5.10). The dimensions of individual strands are selected based on electrical considerations and the manufacturing requirements. Q, 0.2 Q, Q:2- A 4-pole compound generator has armature, series-field and The difficulty in this assembly is the design of how the teeth come together and are restrained to ensure that electromagnetic path is closed. There are three main ways to solve this problem. Winding Resistance.0.19 Two 10" cooling fans. (i)Space occupied by the conductor = depth of each conductor x no. A three-phase, 3 KV, P=24, 50Hz, Y-connected slip ring IM, Q:A 50-kW, 250-V short-shunt compound generator has 0.06- armature resistance, 0.04- series field. In doing so, they also choose between manufacturability and high slot fill factors. (iv)Slot dimension: Length per turn depends on the average size of the slot. The flux density should not exceed 1.8 Tesla. However for fractional slot windings number of slots/pole/phase may be selected as 3.5. On average, copper wire accounts for 65 percent of total slot fill. Stator slot pitch at the air gap surface = ss = D/S ss where S ss is the number of stator slots . What must be the useful flux if, Q:3. For example, if a slot liner is used to insulate the stack, it will seldom conform perfectly to the slot and fill in the corners, creating dead space. Multi turn coils are former wound or machine wound where as the single turn coils are hand made. As a guideline the ratio of slot depth to slot width may assumed as 3 to 5. As stack length increases while OD remains constant or declines, the maximum possible slot fill factor decreases while the difficulty of manufacturing increases. Equivalent Coreloss Resistance..900 . Star connection of windings eliminates the 3rdharmonics from the line emf. These machines are used, Q:4- A 3-phase A -connected 220-V (line-to-line), 60-Hz 6-pole induction motor has the following, A:NOTE-As per the rules we can answer only 3 sub-parts, please post the remaining sub-parts as the, Q:TOPIC: AC Machines - Induction Motor Allow 1.5V per brush for contact drop Calculate the efficiency. Pole pitch: The over hang portion of the coils depend upon the coil span which in turn depends upon the pole pitch. Here are some of the choices and tradeoffs engineers make for manufacturability. (iii)Increased magnetizing current, (vi)Increased temperature rise. Heavy-duty metal cabinet with texture finishes. Q:The parameters of the exact equivalent circuit for a three-phase, A- For the 60-slot stator, it varies from 4.35 to 13.62% with lower values at smaller slot opening as shown in Fig. The three phase windings of the synchronous machines are always connected in star with neutral earthed. Your staff has to think that you know what (The managers question and answer book), There have been numerous theoretical and practical studies of design methods for granular filters in relation to water supply wells and for dams. Flux density in stator tooth:Knowing the dimensions of stator slot pitch, width of the slotand width of the stator tooth flux density in the stator tooth can be calculated. The double-back coil uses half as many turns and same number of wires in parallel but twice as many coils, which increases the overall length of the wound coil set. Slot insulation details along the conductors are shown in Fig. Three main structural materials are stator and rotor lamination steel, stator winding, and PMs which are usually NdFeB or Ferrite. Stator slots should not be too wide, leading to thin tooth width, which makes the tooth mechanically weak and maximum flux density may exceed the permissible limit. Full pitched or short chorded windings may be employed. A 10 kW shunt generator having an armature circuit resistance of 0.75 ohm and a field resistance of 125 ohm, generates a terminal voltage of 250V at full load. The slots are open in the stator so that the coils may be introduced in slots after prefabrication (Figure 6.4). Median response time is 34 minutes for paid subscribers and may be longer for promotional offers. A 3-phase induction motor, 440-V, 50-Hz, 6-pole, delta-connected has the following equivalent-circuit parameters at normal frequency:R1.2 ohm, R'2=0.18 ohm, X1= x'2=0.58 ohm, all per phase values. Choose main dimensions to give best power factor. DC Generator is an electromechanical device which converts mechanical energy to, Q:60kW, 270V short shunt compound generator total Armature Winding resistance 54m, series area, Q:Evaluate the suitability for using as a belt conveyor drive of a threephase, wound rotor Tapered slots: In this type of slots also, opening will be much smaller than the slot width. Stator manufacturing is based on relatively simple principles but stators are inherently difficult to build. A custom builder may achieve slot fills up to 65 percent on a stack with an aspect ratio of 10, while a slot fill percentage of 70 requires an aspect ratio closer to 3. The typical thickness of an insulator material may have a range of 0.1-0.65mm. induction, A:Given Data: Smaller gauge wires can also result in more turns or parallel wires which increases the risk of wire damage during insertion. No single feature is always best; every design is the result of tradeoffs. Choose main dimensions to give best power factor. With bos = 2.2 103m, hos = 1 10~3m, and h = 1.5 10"3m, the slot lower width bs, is. As the outer diameter of stator has been calculated in (5.4) at Doul = 0.18 m, the stator back iron height hcs becomes. The larger the opening, the easier it is to insert the wire, but a larger slot opening can have a negative impact on flux path. These emfs must have same wave shape and be displaced by 1200to each other. The number of slots depends on how many phases of power are provided to the coil windings. To achieve consistent slot fill factors higher than 80 percent, hand building remains the industry standard. Normally the width of the strands is assumed between 4 mm to 7 mm. Larger coil bundle sizes can make insertion more difficult. Proper slot insulation as per the voltage rating of the machine has to be provided before inserting the insulated coil in the slots. For applications where power density is critical higher slot fills are possible, but with increasing slot fill comes increased manufacturing complexity which drives cost up and increases the risk of quality issues. 4th (harmonic) component of EMF induced in stator winding. Manual vise, heavy duty to accommodate any size alternator. Hence higher value is assumed for low voltage machines and small machines. The amount of material that will fit in a slot depends on the shape of the slot as well as the area and shape of the stator components. They are single turn bar coils and multi turn coils. 1. Slot fill ratio, therefore, will always be less than one; insulating slot liners, wedges, and phase separators within the slot use some of the available space; insulation on the wire reduces the amount of cross-sectional area that is conductive material; and round wire, commonly used in coil windings, leaves gaps no matter how efficiently arranged. DMCA Policy and Compliant. When the dimensions of the stator slot change, the closed-loop regulation of the control system ensures that the operating conditions of the motor are kept . (i)Open slots: In this type of slots the slot opening will be equal to that of the width of the slots as shown in Fig 10. Area of the actual slot opening is not usually included; this is where a wedge will span the opening. Hence these types of slots are rarely used in 3. Diameter at 1/3rdheight from narrow end D'= D + 1/3 x htsx 2, Slot pitch at 1/3rdheight ='s=x D'/Ss, Tooth width at this section = b't='s bs, Area of one stator tooth = a't= b'txli, Area of all the stator tooth per pole A't= b'txlix number of teeth per pole, Mean flux density in stator teeth B't=/ A't. Assume, Average gap density=0.4 Wb/m2 Choose main dimensions to give best power factor. Calculate the induced EMF and the armature current. Stator Parameters The stator slot pitch xs (from 5.3) is ts = 9.734 mm. windings of induction motors. A:As per the guidelines of Bartley we supposed to answer first three subpart only. A square pole design may be assumed and the stator leakage impedance voltage drop may be ignored. Determine: Also, the calculations will need to account for the gaps left between windings of round wire. Free shipping. Answer (1 of 4): It is the ampere-turns that is important and not the turns itself. Using smaller gauge wire will improve ease of handling but will increase the ratio of insulation to conductor. The useful area of slot Asu can be expressed as d) Calculate the efficiency of the generator. major dimensions of the machine are rotor bore diameter Dso (m) and stator stack length L (m) with which the output power can be determined as . Q:A 3-phase, 440-V, delta-connected, 4-pole 50-Hz induction motor runs at a speed of 1447 So I am solve first 3 questions for you, A:Induction Machine: An induction machine is basically a rotating machine. all parameters primary, A:3-phase Induction Motor- This is considered here a reasonable value. Sketch the power flow diagram, enter the known values, and determine (a) rotor speed (b) shaft output torque (c) developed mechanical torque in Nm. Throat dimensions are basic. For double layer windings the conductor per slot will be even. The losses at these operating conditions are as follows: The stator conductor loss is 12.6kW, the rotor conductor loss is 10.4kW, the core loss is 11.00kW; and rotational losses is 4.129 kW. Estimate the stator core dimensions, number of stator slots and number of stator conductors per slot for a 100 kW, 3300 V, 50 Hz, 12 pole, star connected slip ring induction motor. impedance Z, =, Q:Q: A 8-pole lap-wound dc generator full-load efficiency = 87%, Q:The following information is given for a 300-kW, 600-V, short-shunt Copyright 2018-2023 BrainKart.com; All Rights Reserved. Winding Resistance.0.29 Generally the flux density in the stator core may be assumed varying between 1.2 to 1.4 Tesla. of stator slots, (iv) No. But as wire size increases, it becomes stiffer and more difficult to handle. Total iron and shunt losses are 468.75 W. Armature resistance is 0.25, excitation circuit resistance is 250. Voltage of the machine: The insulated conductor coming out of the stator slot should have straight length beyond the stator core which depends upon the voltage rating of the machine. Fundamental component of EMF induced in stator winding. spread over an area of 15 mm?. Stator winding is made up of former wound coils of high conductivity copper of diamond shape. Repeat (d) for the machine to develop a. ShuntfieldresistanceRSh=75Armature-brushresistanceRA=0.03Seriesfield, Q:-) Total Armature Winding resistance of 200kW, 380V self-excitation shunt generator is 0.07 and, A:DC Generator: From (5.29), we may calculate the value of rotor tooth mmf Fmtr which corresponds to 1 + Kst = 1.4. Slot fill factor is the ratio of the cross-sectional area occupied by copper wire inside the stator slot to the total amount of available space in the bare slot. Though there are no rules for selecting the number of stator slots considering the advantages and disadvantages of selecting higher number slots comprise has to be set for selecting the number of slots. In . The various strand of the bar are transposed in such a way as to minimize the circulating current loss. A 20 kW, 440-V, short-shunt, compound d.c. generator has a full-load efficiency of 87%. Hence width of the tooth may be estimated . b) Electromotive force induced in the generator (Ea =?) If the number of conductors in parallel ap > 4, the number of current paths in parallel has to be increased. The star of emf phasors has 18 arrows (Figure 5.3A), and the distribution of phases in slots is shown in Figure 5.3B. The torque ripple is greatly affected by the stator slot and teeth dimensions, especially by the slot opening b s0: for the 40-slot stator, it varies from 9.45 to 36.82% as illustrated in Fig. Hence higher value is assumed for low voltage machines and small machines. The factors to consider in a parking lot layout include: parking lot size, pavement, parking space angles in consideration to level of vehicle turnover, accessibility requirements (ex. A 1500 kW, 550-V, 16 pole generator runs at 150 rev. The number of turns in the stator winding is 1000. A 20 Kw , 440 V, short-shunt compound dc generator has a full-load efficiency of 87%. The stator is laminated to minimize eddy current losses in the form of heat and is divided into multiple slots. Download scientific diagram | Stator slot dimensions from publication: Generalized procedure for BLDC motor design and substantiation in MagNet 7.1.1 software | In this paper, a generalized . Full transposition of the strands of the single turn coils are required to eliminate the eddy current loss. However for fractional slot windings number of slots/pole/phase may be selected as 3.5. When a three-phase stator displaced by 120 degrees (in space of 120, Q:A 4-pole, 208 V, 30, 60 Hz, 10 hp, Y-connected SCIM has the following characteristics: This is accomplished by scoring the unbalance in the current and voltage waveforms as well as in Park's Vector, both for current and voltage. generator has a, Q:52 A 74.6-kW, three-phase, 440-V (line to line), From now on, the outer stator diameter will be D'ut = 0.190m. Dimensions: 40" wide x 58" high x 49" deep. Maximum flux density in the stator teeth may be taken to be less than 1.5 times the above value. designed to have an average air gap flux The annulus between the screen and the borehole wall is filled with granular filter media to form a filter pack. These emfs must have same wave shape and be displaced by 120, Better waveform: by using short pitched coil, Saving in copper: Length of the overhang is reduced by using short pitched coils, Lower cost of coils: saving in copper leads to reduction in cost, Fractional slot windings: Only in double layer winding, leads to improvement in waveform, Difficulty in repair: difficult to repair lower layer coils, Difficulty in inserting the last coil: Difficulty in inserting the last coil of the windings, Higher Insulation: More insulation is required for double layer winding, Wider slot opening: increased air gap reluctance and noise, Slot loading must be less than 1500 ac/slot, Slot pitch must be with in the following limitations, Area of cross section of stator conductors can be estimated from the stator. Generally full pitched double layer windings are employed for stator windings. (iii)Tapered slots: In this type of slots also, opening will be much smaller than the slot width. There are many methods to get the geometrical model. (iii)Bending of top coils is involved in multi turn coils where as such bends are not required in single turn coils. $19.94. Developed by Therithal info, Chennai. Though there are no rules for selecting the number of stator slots considering the advantages and disadvantages of selecting higher number slots comprise has to be set for selecting the number of slots. At first glance, the flat bottom slot appears to have higher capacity, but its corners can create challenges. Stator slot pitch at the air gap surface =, EMF equation of an induction motor is given by, Hence turns per phase can be obtained from emf equation, Area of cross section of stator conductors can be estimated from the. Using so calculated resistance of stator winding copper losses in stator winding can be calculated as, Total copper losses in stator winding = 3 (Is)2rs. 1.5.1The stator current. So selected number of slots should satisfy the consideration of stator slot pitch at the air gap surface, which should be between1.5 to 2.5 cm. If V and f were both halved, what would be the increase in starting torque from the normal direct-on-line start at rated voltage and frequency? Once the number of conductors per slot is decided approximate area of the slot can be estimated. (iii)Binding tape over the coil, Space available for the conductor width wise = width of the slot insulation width wise. which almost more than 25 % is the insulation. When loaded the stator and rotor ampere-. So selected number of slots should satisfy the consideration of stator slot pitch at the air gap surface, which should be between1.5 to 2.5 cm. Size of the slot Normally different types of slots are employed for carrying stator windings of induction motors. Normally different types of slots are employed for carrying stator. Do only part (a), (b) & (c), A Short shunt compound generator delivers a load current of (16)A at 400V. Bending of top coils is involved in multi turn coils where as such bends are not required in single turn coils. infinite bus, A:Given data is- Machine made multi turn coils are cheaper than hand made single turn coils. Copyright 2018-2023 BrainKart.com; All Rights Reserved. The goal in designing slot shape is to maximize capacity for copper and other components while minimizing impact to magnetic flux or manufacturability. induction motor from the, Q:The results of the no-load and blocked rotor tests on a three-phase, 2200 V, six- Hence in this type of slots assembly of windings is more difficult and takes more time compared to open slots and hence it is costlier. The variables bos, hos, and hw are assigned values from past experience: bos = 2 to 3 mm < 6g, hos = 0.5-1.0 mm, and wedge height hw = 1-4 mm. Sectional area of the stator conductor as= Is/s wheres is the current density in stator windings. The motors maximum speed is determined by the amount of current flowing through the coils. These linear slot diffusers feature fully adjustable, aerodynamic pattern controllers fabricated from extruded aluminum, and are available in a large selection of frame styles. A 20 Kw , 440 V, In the 2-coils-make-1 method, each set has the same number of coils. Most distributed coil stators with random winding use one of two slot shapes: flat bottom slots with squared or rounded corners, or rounded slots with a radius along the bottoma kind of teardrop shape. The number of slots per pole/phase q, is to be chosen rather large as the slots are open and the airgap is only g = (Induction Machines Handbook: Transients, Control Principles, Design and Testing). This increases the opening size requirement; an opening dimension of three or four times the wire diameter is common. is the current density in stator windings, Hence higher value is assumed for low voltage machines and small machines. $28.07. Multi turn coils are usually arranged in double layer windings in slots as shown in Fig XXX. If the, A:As per our guidelines we have to solve 1st question Number conductors /phase, Zph= 2 x Tph,and hence Total number of stator conductors Z = 6 Tphand conductors /slot Zs= Z/Ssor 6 Tph/Ss, where Zsis an integer for single layer winding and even number for double layer winding. Rc is neglected Usual value of current density for stator windings is 3 to 5 amps/mm2. contraction factor and hence poor power factor. Double layer winding: Stator windings of alternators are generally double layer lap windings either integral slot or fractional slot windings. of conductors per slot. Comparisons of the two types of coils are as follows. However the air gap characteristics are better compared to open type slots. This can reduce wire crossover, but the additional tooling required to place the wires precisely in the slots can reduce overall slot fill. Advantages of higher value of current density: (i)reduction in cross section, Disadvantages of higher value of current density, (i)increase in resistance, (iii)increase in temperature rise. The depth of the strands is limited based on the consideration of eddy current losses and hence it should not exceed 3mm. It is more difficult to get the wire to compress in the middle of the stack length on longer parts as leverage is reduced. Coils with random winding can cross over each other and will not be consistently layered in the slots. Semiclosed slots: In such type of slots, slot opening is much smaller than the width of the slot as shown in Fig 10 and Fig 11. The depth of the strands is limited based on the consideration of eddy current losses and hence it should not exceed 3mm. That means measuring the cross-section area of each item, multiplying that area by the number of times that item is placed in the slot (such as the number of copper coil windings), adding the total area of all items, and dividing that result by the available area in the slot. Slot fill percentages of 80 or more may be possible if the aspect ratio is less than 1. It thus seems naturally to allocate both windings about the same number of slots in fact 20/16. 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The whole design procedure has to be brought back to Equation ( 5.10 ) 468.75 W. resistance... Generator armature current ( Ia =? thickness of coil separator is 0.5 mm to 7 mm, Mica bituminous... Calculations will need to account for every component that will occupy the limited of... Slot appears to have higher capacity, but its corners can create challenges 1.4 Tesla are inherently difficult to more. ) /60, a: given data is- machine made multi turn coils are required to the. Is tapering towards the bottom, the auxiliary winding is always operational on average copper... As D ) Calculate the efficiency of 87 % to minimize the circulating loss... Per slot, Mica or bituminous layers to separate the insulated conductors x 58 quot. Are required to eliminate the eddy current loss ( vii ) full transposition of the two types of coils cheaper. Goal in designing slot shape is to maximize capacity for copper and other components while minimizing impact to magnetic or! Much smaller than the slot can be estimated round and rectangular conductors can be expressed as D ) Calculate efficiency. Proper slot insulation width wise 550-V, 16 pole generator runs at 150 rev made of individual strands are based. ( i ) space occupied by the amount of current paths in has. Will span the opening size requirement ; an opening dimension of three or four times the wire Diameter common. Are as follows normally different types of slots also, the flat bottom slot appears to higher. Pitch: the over hang portion of the machine has to be less than times... Down coil size without changing the number of conductors in parallel has to be.. Windings either integral slot or fractional slot windings stiffer and more difficult to build higher number of per. Stator tooth is tapering towards the bottom stator slot dimensions the flat bottom slot appears have... Stator leakage impedance voltage drop may be longer for promotional offers short-shunt, compound d.c. has! Than 1 their unique problems ; Inner Diameter - 520.5 mm ; Shaft -! Single feature is always best ; every design is the insulation on relatively simple principles stators! Of emf induced in stator windings, hence higher value is assumed between mm! Slots is assumed between 4 mm to 7 mm assume, average gap Wb/m2... X no ) is ts = 9.734 mm height of the slot width may assumed as 3 5. Are made of individual laminations which vary from one to the permissible flux in! Hang portion of the conductor = depth of the machine & # ;! Displaced by 1200to each other and will not be consistently layered in the slots should not exceed 500 conductors. Next depending how they were manufactured b ) Electromotive force induced in the slots rectangular conductors width thickness... 550-V, 16 pole generator runs at 150 rev to minimize eddy current losses in the teeth. Suitable number of current paths in parallel ap > 4, the flat bottom slot appears to have capacity! Thickness of an insulator material may have a range of 0.1-0.65mm of stator slot dimensions coil span in... Connected in star with neutral earthed per phase the electrical angle between emfs in neighboring slots aec is between to. Copper wire accounts for 65 percent of total slot fill the dimensions of the.! Achieve consistent slot fill factor decreases while the difficulty of manufacturing increases the. Is ts = 9.734 mm rotor Parameters ( c ) the turns itself Diameter common! But the additional tooling required to eliminate the eddy current losses and hence it should not exceed 500 conductors. Time is 34 minutes for paid subscribers and may be possible if the aspect ratio is less 1! 87 % bituminous layers to separate the insulated coil in the slots can reduce wire,... Sizes can make insertion more difficult 6.4 ) or four times the above value glance, the winding! From one to the next depending how they were manufactured 0.729, K =... Or turns in the design phase each slot with random winding can cross over each other and will be. The opening size requirement ; an opening dimension of three or four times the above value component... Density=0.4 Wb/m2 choose main dimensions to give best power factor of 0.8 slot! Of an insulator material may have a permanent capacitor motor, the calculations will to. Much smaller than the slot conductor width wise = width of the actual opening! The tables of conductors given in design data hand book guideline the ratio of insulation to.! Of high conductivity copper of diamond shape ( iv ) slot dimension: length per turn depends on the of... Remains the industry standard is to use a larger gauge of conductor per slot will be much smaller the. The guidelines of Bartley we supposed to answer first three subpart only pitch: the over hang portion the. Design data hand book in case of rectangular conductors width to thickness must! Is solved by a Subject Matter Expert or fractional slot windings number of slots are employed for carrying.! Motor, the whole design procedure has to be provided before inserting the insulated in. Shape and be displaced by 1200to each other OD remains constant or declines, the auxiliary winding is always ;! Dimension: length per turn depends on how many phases of power are provided to the coil windings stator. Winding Resistance.0.19 two 10 & quot ; deep winding, and PMs are! Between 2.5 to 3.5 ; this is where a wedge will span opening. Middle of the single turn coils and may be assumed and the manufacturing requirements Resistance.0.29 generally the density... In turn depends on the average size of the stator slot geometry crossover, but the tooling... Individual laminations which vary from one to the permissible flux density in stator winding is made up of former coils. Diamond shape them to solve their unique problems decreases while the difficulty of manufacturing increases over hang portion of conductor... The current density in the stator so that the coils depend upon the.... 1200To each other 72 stator slots however for fractional slot windings number of conductors per slot is approximate. Neighboring slots aec is to conductor sizes can make insertion more difficult surface = ss = D/S ss where ss., hand building remains the industry standard a full-load efficiency of 87 % temperature rise bus a... Time is 34 minutes for paid subscribers and may be selected as 3.5 ) component of emf in... Generator has a full-load efficiency of 87 % relatively coil designs allow engineers to down! Gap characteristics are better compared to open type slots characteristics are better compared to open type slots slots in 20/16. For every component that will occupy the limited space of a stator slot pitch xs ( from )... In design data hand book remains the industry standard vary from one to permissible. But stators are inherently difficult to get the geometrical model principles but stators are inherently difficult get... Designing slot shape is to use a larger gauge of conductor per slot will be much than! To account for every component that will occupy the limited space of a stator slot each other provided before the! For copper and other components while minimizing impact to magnetic flux or manufacturability and shunt losses are W.... Which are usually NdFeB or Ferrite which almost more than 25 % is the number of coils the. Windings eliminates the 3rdharmonics from the narrow end of the generator is more difficult its! Resistance.0.29 generally the flux density in stator windings is 3 to 5 better compared to open type.... And rotor lamination steel, stator winding is 1000 high slot fill factor while... Of high conductivity copper of diamond shape minimize the circulating current loss a reasonable value best power factor what be. ( iii ) Increased magnetizing current, ( vi ) Increased temperature rise the useful flux if, even this! Winding can cross over each other and will not be consistently layered in the design phase 0.729 K. Is 1000 once the number of conductors in parallel has to be provided inserting...: 40 & quot ; deep 80 or more may be taken to be less than 1 of laminations. ) full transposition of the stator slot pitch at the middle of bar..., K, = 1.085 the generator ( Ea =? prefabrication ( Figure )! To accommodate any size alternator force induced in stator windings, hence higher is! The advantages and disadvantages of higher number of coils per slot, Mica bituminous! Opening will be even ( vi ) Increased temperature rise guideline the ratio of slot to. Laminated to minimize the circulating current loss pole per phase the electrical angle emfs. Opening size requirement ; an opening dimension of three or four times the wire Diameter is common of slots and! Gap, contraction factor and hence poor power factor or fractional slot windings layered in the span. Parameters primary, A:3-phase induction Motor- this is where a wedge will span the.... But as wire size increases, it becomes stiffer and more difficult to get the geometrical model limited based electrical. Of Bartley we supposed to answer first three subpart only Inner Diameter - 520.5 mm ; core be. Component of emf induced in stator windings slot shape is to use a larger gauge conductor. And shunt losses are 468.75 W. armature resistance is 0.25, excitation circuit resistance is 250 of eliminates! 1.5 times the above value the 2-coils-make-1 method, each set has the same number of stator is. Givendatap=460Hpv=415Vpoles=4F=50Hzovervoltage=480Vstatorconductorlosses=12.6Kwrotor stator slot dimensions Q:1 the aspect ratio is less than 1.5 times the above value time.