Brushed DC Motor Fundamentals

The equivalent electrical circuit of a dc motor is shown in figure 5.2. It can be represented by a voltage source (Va) across the coil of the armature. The electrical equivalent of the armature coil can be described by an inductance (La) in series with a resistance (Ra) in series with an induced voltage (Vc) which

Brushless motors are a bit similar to normal DC motors in the way that coils and magnets are used to drive the shaft. Though the brushless motors do not have a brush on the shaft which takes care of switching the power direction in the coils, and this is why they are called brushless. Instead the brushless motors have three coils on the inner (center) of the motor, which is fixed to the mounting. On the outer side it contains a number of magnets mounted to a cylinder that is attached to the rotating shaft. So the coils are fixed which means wires can go directly to them and therefor there is no need for a brush. The reason why QuadCopters use brushless motors instead of normal DC motors is the much higher speeds and less power usage for the same speed. The brushless motors are more efficient as there is no power lost as there is in the brush-transition on the DC motors. Usually rated with a KV rating (revolutions per volt). This is not equivalent to torque, but lower KV motors are usually used for larger

The electric motors work by electricity and magnets working together. Once the electricity gets going, the magnets take over. The magnets keep the motor going because the magnets used in motors have both positive and negative magnets on both sides. Surrounding the magnetic ends, are one positive and one negative magnet. This means that at any

“The discovery of a relationship between electricity and magnetism made possible the invention of the electric motor” (Electric Motors, 2008). Without one or more fixed magnets combined with a movable current-carrying coil, electric motors will not run. Pinball machines, paintball markers, dot matrix printers and fuel injectors in vehicles all use magnets by means of electromechanical solenoids. A solenoid is “a tightly wound helix of current-carrying wire (which) acts like a hollow bar magnet” (Electricity and Magnetism,

Two types of shaft bearings: The aft-most tunnel bearing and all others. The former type of bearing has 2 bearing shells, one on the top and the other on the bottom because it must act against the propeller mass and take an upward thrust at the forward end of the tail-shaft. Whereas as the other type of shaft bearings resist only the shaft weight and thus require only bottom bearing shells. The usual journal bush is replaced by pivoting pads, because the tilting pad can carry high overloads and retain a thick oil lubrication film.

Electric motors rely on the force of an electromagnet, as does every electric motor. An electromagnet is created when a current flows through the copper wire. The electromagnet forms a magnetic field around the coil. A magnetic field is the area around a magnet where its force can be detected. This magnetic field causes another force which is called polarity. Polarity describes two areas (north and south poles) of the magnet were the force of the magnet is the strongest.

Minnesota Micromotors, Inc. (MM), based in Minneapolis, was a manufacturer of brushless, direct current (BLDC)1 motors used in orthopedic medical devices. Devices utilizing MM’s motors were typically used by orthopedic surgeons in large bone surgery, reconstructive surgery, trauma surgery, and sports medicine procedures. MM sold approximately 97,000 motors a year and had a 9% share of the $137 million U.S. medical motor market for orthopedic and neurosurgery devices. (See Exhibit 1A.) MM was a division of privately held Fractional Motors Limited, which had revenues of $350 million (just over $12 million, or 3%, generated by MM) and

1) Explain briefly how the circular motion of a rotor with permanent magnets generates an induced EMF in a stator winding and how it generates voltage during rotation

Brushless direct current (BLDC) motors are preferred as small horsepower control motors because their efficiency is very high, the operation is in a silent mode, has a compact form, contains high precision, low maintenance, Its structure is simple, and has a large torque, etc. Hence, it is extensively used in national defense, aerospace, robotics, industrial process control, precision machine tools, automotive electronics, household appliances and office automation [1].

Electrical machines have gained a distinctive interest by experts because their advantages are indisputable because of their ability to adapt to any environment and their efficient efficiency, thus exceeding other non-electric actuators. The induction machine (IM) is currently the most widely used electrical machine in both domestic and industrial applications. Its main advantage lies in its simplicity of mechanical and electrical design (absence of rotor winding (cage machine) and collector, simple structure, robust and easy to build .....). However, these advantages are accompanied by a high degree of physical complexity, linked to the electromagnetic coupling between the magnitudes of the stator and those of the rotor. This is why, for a long time, IM was only used in constant speed drives.(El-kharashi and El-dessouki, 2014).

This project aim name shows that the speed of lift by dc motor which controlled by armature voltage control method. These project help in our daily life as well as transport residents to different floors, hospital emergency etc. In these project the conversion of electric energy into mechanical energy by the dc motor and these mechanical energy used in the lift. The speed of lift varies by the armature voltage of dc motor. The DC motor which is excited by dc supply using inverter. The dc motor start rotating. The shaft is connected from dc motor to the pulley. so the mechanical energy supply to the pulley and pulley start rotating. So the lift move from upward and downward with help of rotating pulley. Reverse and forward speed of dc motor which is change by the change over switch. the speed increase and decrease or control according to loaded lift by the field regulator. There are some condition we have to maintain as well as rated capacity in weight, maximum load etc.

Brushless direct current (BLDC) motors are preferred as small horsepower control motors because their efficiency is very high, the operation is in a silent mode, has a compact form, contains high precision, low maintenance, its structure is simple, and has a large torque, etc. Hence, it is extensively used in national defense, aerospace, robotics, industrial process control, precision machine tools, automotive electronics, household appliances and office automation [1].

currents) from stationary reference frame to torque and flux producing currents components in rotating reference frame. The vector control of the PM synchronous motor is derived from its dq dynamic model. Considering the currents as inputs, the three currents are:

The electrical power is alternating current but DC motors needs a rectifier to convert that into direct current.

❖ In DC generator, the armature winding is mechanically rotated through the stationary magnetic fields created by the electromagnets or permanent magnets.