What type electric drive is used in cranes?

Conventional AC operated crane drives use slip ring induction motor whose rotor windings are connected to power resistance in 4 to 5 steps by power contactors. Reversing is done by changing the phase sequence of the stator supply through line contactors. Braking is achieved by plugging.

Why is DC series motor used in crane?

DC series motor is best suited for DC traction, cranes as it provides high starting torque and easy speed control which is primary requirement of DC traction.

What are the types of electric drive?

There are three general categories of electric drives: DC motor drives, eddy current drives and AC motor drives. Each of these general types can be further divided into numerous variations. Electric drives generally include both an electric motor and a speed control unit or system.

What are the types of electric drives used in industry?

Types of Electrical Drives

• AC Motor drives. ...
• DC Motor drives. ...
• Individual. ...
• Multi Motor. ...
• Group Drive. ...
• Constant Speed drive. ...
• Variable Speed drive. ...
• Vector Control Drive.

Which drive are widely used?

DC drives have been widely used in industrial drive applications in order to offer very precise control.

What is the difference between AC and DC drives?

The “AC” stands for alternating current. AC-type drives are also known as adjustable speed drives, adjustable frequency drives, and variable speed drives. In contrast, DC drives are used to convert alternating current into direct current (The “DC” in DC drives is an acronym for direct current).

What is the disadvantage of DC drive?

The disadvantage of D.C. drives is the presence of a mechanical commutator which limits the maximum power rating and the speed. ... The variable speed applications are dominated by D.C. drives because of lower cost, reliability ad simple control.

What is group electric drive?

when one prime mover or motor is used for the number of machine tools on common shaft then the drive is called as group drive . it is also sometimes called as line shaft drive. Cost of group drive is less for given capacity of load.

What drives an electrical load?

An electrical load is an electrical component or portion of a circuit that consumes (active) electric power, such as electrical appliances and lights inside the home. The term may also refer to the power consumed by a circuit. This is opposed to a power source, such as a battery or generator, which produces power.

Which DC motor is preferred for crane and hoist?

Which DC motor is generally preferred for cranes and hoists? Explanation: DC series motor is used where high starting torque is required, thus in cranes and hoists DC series motor is used widely.

Why starting current is high?

Starting current of induction motor is as high as 5 to 7 times the normal full load current. Therefore different starting of induction motor, methods such as (star delta starter, auto transformer starter and other starting methods) are employed in order to reduce the high starting currents of induction motor.

What is hoist motor?

Hoist Geared Motor

A hoist is a device used for lifting or lowering a load by means of a drum or lift-wheel around which rope or chain wraps.

What are the 5 types of electrical loads?

Electrical Loads can be classified according to the nature of the load as follows:

• Resistive Electrical Loads.
• Capacitive Electrical Loads.
• Inductive Electrical Loads.
• Combination Electrical Loads.

What is capacitive load?

Capacitive loads include energy stored in materials and devices, such as capacitors, and cause changes in voltage to lag behind changes in current. Capacitive loads are less common than inductive and resistive loads, but are becoming more common with the deployment of increasingly complex electronics.

What is electric load example?

An electrical load is simply any component of a circuit that consumes power or energy. In a household setting, the most obvious examples of electrical loads include light bulbs and appliances.

What is eddy current Drive?

An eddy current drive, also known generically as a magnetic drive, eddy current clutch or magnetic clutch, is an electro-mechanical variable speed drive that uses a constant speed motor as the input. The eddy current drive is installed between the motor and the driven equipment.

What is an individual electric drive?

Individual-wheel drive or IWD is a wheeled vehicle with a drivetrain that allows all wheels to receive torque from several motors independent of each other. The term was coined to identify those electric vehicles whereby each wheel is driven by its own individual electric motor.

Why are DC motors more expensive than AC?

DC motors generally cost significantly more than AC motors due to their higher manufacturing costs. Also, because AC induction motors have such widespread use, economies of scale contribute to their relatively lower price.

Why DC motors are preferred over AC motors?

D.C. motor is preferred over an A.C. motor when we need variable speed operation because As in DC series motor field winding and armature winding is in series. So whenever armature current changes field current also changes as they are same due to which its torque changes rapidly and we get a variable speed.

Why are DC motors more efficient than AC motors?

In fact, the DC motor is 30% more efficient than AC motors due to the secondary magnetic field being generated from the permanent magnets rather than copper windings.

What are DC drives used for?

A DC drive supplies voltage to the motor to operate at a desired speed. The motor draws current from this power source in proportion to the torque (load) applied to the motor shaft.

What are AC drives used for?

An AC drive is a device used to control the speed of an electrical motor in order to: enhance process control. reduce energy usage and generate energy efficiently. decrease mechanical stress on motor control applications.

Which drive is best AC or DC?

Experts cite AC drives as more energy efficient, and therefore more cost-effective than their DC counterpart. Furthermore, AC drives can change speed easier than a DC drive can, allowing it to complete complex tasks quickly.

What is tungsten load?

A tungsten load has a lot higher inrush current, cold about 10 times more then hot. For example a 100 Watt, 230 Volts lamp has a very low resistance when cold. (42.9 ohms) Just measured with a calibrated ohm meter. When the filament is hot the resistance increases considerably. (about 529 ohms.)…