For A 5kw Dc Motor The Number Of Slots Per Pole Should Be

1. For A 5kw Dc Motor The Number Of Slots Per Pole Should Bet
2. For A 5kw Dc Motor The Number Of Slots Per Pole Should Be Paid
3. For A 5kw Dc Motor The Number Of Slots Per Pole Should Be Replaced
4. For A 5kw Dc Motor The Number Of Slots Per Pole Should Be Lowered

Number of armature slots in DC machine

For A 5kw Dc Motor The Number Of Slots Per Pole Should Bet

Brushless DC Motors or BLDC Motors have become a significant contributor of the modern drive technology. Their rapid gain in popularity has seen an increasing range of applications in the fields of Consumer Appliances, Automotive Industry, Industrial Automation, Chemical and Medical, Aerospace and Instrumentation. (ii)number of poles per pole arc should be an integer (+ 5 6;. (c) Lap Winding: In case of lap winding the number of slots should be (i)a multiple of pair of poles and (ii)slots per pole arc is an integer (+ 5 6. Number of Coils and Turns per Coil: The minimum number coils is given by C k g l L:EP/15. A dc motor develops a torque of 50Nm while rotating at 600rpm power developed by it is a four pole lap wound DC machine ha 48 slots on the armature with 8 conductors per slot the machine is driven at 1000 revolutions per minute and the useful flux per pole is 30mWb. DC Motor: motor that runs on direct current (DC) electricity. Principle of operation of DC Motor: When current carrying conductor is placed in a magnetic field it experience a force. Construction of DC Motor: 4. Construction of DC Motor: 5. Function of each part of DC Motor: Yoke:. It is outer cover of dc motor also called as frame.

In order to decide what number of slots (more or less) is to be used, the following merits and demerits are considered.

1. As the number of slots increases, cost of punching the slot increases, number of coils increases and hence the cost of the machine increases.

2. As the number of slots increases, slot pitch λ_s = (slot width b_s tooth width b_t) = πD/ number of slots S

decreases and hence the tooth width reduces. This makes the tooth mechanically weak, increases the flux density in the tooth and the core loss in the tooth. Therefore efficiency of the machine decreases.

If the slots are less in number, then the cost of punching & number of coils decreases, slot pitch increases, tooth becomes mechanically strong and efficiency increases, quantity of insulation in the slot increases, heat dissipation reduces, temperature increases and hence the efficiency decreases.

It is clear that not much advantage is gained by the use of either too a less or more number of slots.

As a preliminary value, the number of slots can be selected by considering the slot pitch. The slot pitch can assumed to be between (2.5 and 3.5) cm. (This range is applicable to only to medium capacity machines and it can be more or less for other capacity machines).

For A 5kw Dc Motor The Number Of Slots Per Pole Should Be Paid

The selection of the number of slots must also be based on the type of winding used, quality of commutation, flux pulsation etc.

When the number of slot per pole is a whole number, the number slots embraced by each pole will be the same for all positions of armature. However, the number teeth per pole will not be same.

In order to decide what number of slots (more or less) is to be used, the following merits and demerits are considered.

1. As the number of slots increases, cost of punching the slot increases, number of coils increases and hence the cost of the machine increases.

2. As the number of slots increases, slot pitch λ_s = (slot width b_s tooth width b_t) = πD/ number of slots S

decreases and hence the tooth width reduces. This makes the tooth mechanically weak, increases the flux density in the tooth and the core loss in the tooth. Therefore efficiency of the machine decreases.

If the slots are less in number, then the cost of punching & number of coils decreases, slot pitch increases, tooth becomes mechanically strong and efficiency increases, quantity of insulation in the slot increases, heat dissipation reduces, temperature increases and hence the efficiency decreases.

It is clear that not much advantage is gained by the use of either too a less or more number of slots.

As a preliminary value, the number of slots can be selected by considering the slot pitch. The slot pitch can assumed to be between (2.5 and 3.5) cm. (This range is applicable to only to medium capacity machines and it can be more or less for other capacity machines).

For A 5kw Dc Motor The Number Of Slots Per Pole Should Be Paid

The selection of the number of slots must also be based on the type of winding used, quality of commutation, flux pulsation etc.

When the number of slot per pole is a whole number, the number slots embraced by each pole will be the same for all positions of armature. However, the number teeth per pole will not be same.

This causes a variation in reluctance of the air gap and the flux in the air gap will pulsate. Pulsations of the flux in the air gap produce iron losses in the pole shoe and give rise to magnetic noises. On the other hand, when the slots per pole is equal to a whole number plus half the reluctance of the flux path per pole pair remains constant for all positions of the armature, and there will be no pulsations or oscillations of the flux in the air gap.

To avoid pulsations and oscillations of the flux in the air gap, the number of slots per pole should be a whole number plus half. When this is not possible or advisable for other reasons, the number of slots per pole arc should an integer.

Number of teeth/pole shoe = 5 and flux passes through 5 teeth.

For A 5kw Dc Motor The Number Of Slots Per Pole Should Be Replaced

The reluctance of the air gap is inversely proportional to the area corresponding to 5 teeth.

For A 5kw Dc Motor The Number Of Slots Per Pole Should Be Lowered

This paper presents the design and analysis of a high power radial flux Brushless DC motor for electro-mechanical actuation system. The motor is used for driving an electro-mechanical actuator of 20 ton capacity. Surface mounted, radially magnetized permanent magnet design is mostly preferred due to its ease of control, high efficiency and low maintenance. The motor under consideration is having four set of windings and four set of sensors for redundancy. The motor is rated for a maximum torque of 133Nm (@95A) per winding and a total torque of 532 Nm (@380 A) when all the windings are excited. The speed of the motor is 1850 rpm at a nominal voltage of 270V. The performance evaluation of radially magnetized permanent magnet motors for a three phase, 108 slots, 24 pole BLDC motor was carried out in finite element analysis software COMSOL Multiphysics® software. The number of poles has been chosen such that the motor mechanical envelop has been met and has high efficiency.

Since the motor is used for position control applications, the motor should have minimal cogging torque .In order to achieve this; fractional slot configuration has been chosen. Certain pole slot combinations are preferred. Here 108 slots have been chosen. COMSOL Multiphysics® software (finite element software) is used for computing electromagnetic torque, cogging torque, back EMF, magnetic flux density etc. Inductance calculation by analytical method is difficult and there is no direct relationship also. Moreover the material under consideration is non- linear in nature. So we have done it using Finite element simulation neglecting the end turn leakage inductance.

Inductance is found using energy method and virtual work method, as lower inductance may lead to high torque ripple which is undesirable in servo applications. Sound effects slot machines. The specification was achieved during design.

The motor is modeled using COMSOL Multiphysics® software and torque value was found out using Maxwell's stress tensor method. The air gap flux density is also plotted. There is slight amount of saturation seen in stator core at higher currents in the torque profile, which is expected also. The non linear B-H curve of silicon steel was modeled in finite element software in order to study the saturation effect at high currents. Further reduction in saturation is possible by changing the material to iron cobalt for stator. Due to the presence of the slots, the air gap flux density waveform is having the ripples.

One of the issues faced during the assembly, was the insertion of rotor inside the stator body. The radial force between the stator and rotor handling was difficult. The magnetic pull due to rotor eccentricity was studied and evaluated using finite element method. A fixture is being designed, taking into consideration of radial force.

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