1. 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.
Which DC motor is used for crane and hoist?
Wound field DC motors 4 (series, shunt or compound) are used in industrial environments for coil feeding reels in the milling/metalforming, crane hoists, motor-driven cable reels, and elevator hoist motors.
Why are DC series motors used in cranes?
The starting torque of the DC series motor is proportional to the square of the armature current. … That is why DC series motor is capable to produce high starting torque, and it is preferred for driving heavy loads. The high inertia loads like cranes need a high starting torque. The DC series motor is used in cranes.
Which type of DC motor is used in lift?
The latest lift designs use 3-phase induction motors with variable frequency drive electronic controls. Some may also use a similar system with permanent magnet (brush less) DC motors. DC shunt motors.
In which of the applications DC motors are still preferred?
Why are the DC motors preferred for traction applications? Explanation: DC motors are used for traction as, according to the characteristics of DC motors speed is inversely proportional to torque and square of armature current as well, if linear magnetization is concerned.
Which DC motor is generally?
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.
Which DC motor has maximum self loading property?
Which DC motor has got maximum self-loading property? Explanation: A differentially compound DC motor, flux reduces so sharply at small increase in load at higher values of load. It is advisable that motor should not be used beyond some load value, as it may damage itself by self-loading. 5.
Why is the DC motor preferred over AC motor?
DC motors have the advantage of: higher starting torque, quick starting and stopping, reversing, variable speeds with voltage input and they are easier and cheaper to control than AC. AC motor advantages include: lower power demand on start and minimal maintenance.
What will happen if the back EMF of a DC motor vanishes suddenly?
What will happen if the back emf of a DC motor vanishes suddenly? Explanation: If back emf vanishes suddenly, motor circuit will try to retain back emf by drawing more current from supply. If supplying unit didn’t trip down by this time, excess current in armature may heat up the armature. 3.
Why starters are used in DC motor?
Starters are used to protect DC motors from damage that can be caused by very high current and torque during startup. They do this by providing external resistance to the motor, which is connected in series to the motor’s armature winding and restricts the current to an acceptable level.
Which motor is used in fan?
In conventional ceiling fans, single phase induction motor is used. These motors consume minimum power and hence, are also known as fractional kilowatt motors. A single phase induction motor requires only one power phase for operating. It converts the electrical energy from the power input into mechanical energy.
What is difference between brushless DC motor and brushed DC motor?
What is the Difference Between Brushed and Brushless DC Motors? A brushed DC motor uses a configuration of wound wire coils, the armature, acting as a two-pole electromagnet. … A brushless motor, by contrast, utilizes a permanent magnet as its external rotor.
Which motor is used in lift?
Conventionally, there are, in general, three types of motors used in elevator systems: AC, DC and a hybrid between the two. The AC-2 motor is a primitive motor drive popular at least half a century ago for low-speed elevators. It is usually coupled with a worm gear to reduce speed and increase driving torque.
Which motor is not suitable for use as a DC machine?
Solution(By Examveda Team)
The squirrel cage motor is the only one without any connection to the armature.
Which power is mentioned on a name plate of a motor?
This data tells you at which voltage the motor is made to operate. Nameplate-defined parameters for the motor such as power factor, efficiency, torque and current are at rated voltage and frequency. When the motor is used at other voltages than the voltage indicated on the nameplate, its performance will be affected.
Which DC motor is most suitable for high starting torque applications?
Series wound DC motors are best for applications that require high startup torque, without the need for speed regulation. Like a shunt motor, as a load is applied to a DC series motor, the motor speed decreases, which reduces the back EMF and increases the net voltage.