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Industrial applications use dc motors because the speed-torque relationship can be varied to
almost any useful form -- for both dc motor and regeneration applications in either direction of
rotation. Continuous operation of dc motors is commonly available over a speed range of 8:1.
Infinite range (smooth control down to zero speed) for short durations or reduced load is also
Dc motors are often applied where they momentarily deliver three or more times their rated
torque. In emergency situations, dc motors can supply over five times rated torque without
stalling (power supply permitting).
Dynamic braking (dc motor-generated energy is fed to a resistor grid) or regenerative braking (dc
motor-generated energy is fed back into the dc motor supply) can be obtained with dc motors on
applications requiring quick stops, thus eliminating the need for, or reducing the size of, a
Dc motors feature a speed, which can be controlled smoothly down to zero, immediately
followed by acceleration in the opposite direction -- without power circuit switching. And dc
motors respond quickly to changes in control signals due to the dc motor's high ratio of torque to
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Application of DC Shunt Wound Electric Motor:
The characteristics of a DC shunt wound motor give it very good speed regulation, and it is
classified as a constant speed motor, even though the speed does slightly decrease as load is
increased. Shunt-wound motors are used in industrial and automotive applications where precise
control of speed and torque are required.
Typical Shunt Wound DC Motor speed-torque relationship is shown below.
A shunt-wound DC motor has a decreasing torque
when speed increases. The decreasing torque vs
speed is caused by the armature resistance voltage
drop and armature reaction. At a value of speed
near 2.5 times the rated speed, armature reaction
becomes excessive, causing a rapid decrease in
field flux, and a rapid decline in torque until a stall
condition is reached.
Shunt-Wound Motor Applications The characteristics of a shunt-wound motor give it very good speed
regulation, and it is classified as a constant speed motor, even though the speed does slightly
decrease as load is increased. Shunt-wound motors are used in industrial and automotive
applications where precise control of speed and torque are required.
TYPES OF DC MOTORS DC Motors Series-Wound Motor Figure 9 Torque-vs-Speed for a
Series-Wound Motor Since the armature and field in a series-wound motor are connected in
series, the armature and field currents become identical, and the torque can be expressed as
shown in Equation (6-8). (6-8) T KI 2
a The torque-vs-speed characteristics of a series-wound
motor with a constant voltage source are shown in Figure 9. As the speed decreases, the
torque for a series- wound motor increases sharply. As load is removed from a series motor,
the speed will increase sharply. For these reasons, series-wound motors must have a load
connected to prevent damage from high speed conditions.
Series-Wound Motor Applications The advantage of a series-wound motor is that it develops a
large torque and can be operated at low speed. It is a motor that is well-suited for starting heavy
loads; it is often used for industrial cranes and winches where very heavy loads must be moved
slowly and lighter loads moved more rapidly.
Compounded Motor The compounded motor is desirable for a variety of applications because it
combines the characteristics of a series-wound motor and a shunt-wound motor. The compounded
motor has a greater torque than a shunt motor due to the series field; however, it has a fairly constant
speed due to the shunt field winding. Loads such as presses, shears, and reciprocating machines are
often driven by compounded motors.
DC Motors TYPES OF DC MOTORS S In a shunt-wound motor, the field is in parallel, or "shunts" the armature.
In a series-wound motor, the field is in series with the armature.
A compounded DC motor is constructed so that it contains both a shunt and a series field.
A shunt-wound DC motor has a decreasing torque as speed increases.
The characteristics of a shunt-wound motor give it very good speed regulation, and it is classified as a
constant speed motor, even though the speed does slightly decrease as load is increased.
A series-wound motor has a rapidly increasing torque when speed decreases. As load is removed from a
series-wound motor, the speed will increase sharply.
The advantages of a series-wound motor are that it develops a large torque and can be operated at low
speed. It is a motor that is well-suited for starting heavy loads.
Hansen Permanent Magnet DC Motors have unique performance advantages that make them the best
choice for simple, high efficiency DC drives and servo motors. Hansen Permanent Magnet DC Motors
provide nearly instantaneous torque and higher torque overall than wound field motors. With these
torque characteristics and a linear speed torque curve, Hansen Permanent Magnet DC Motors are
perfect for demanding use, especially in applications requiring high starting torque and low inertia loads.
An added benefit of DC motors is easy reversibility by simply changing polarity.
Mobility (Motorised wheelchairs & stairlifts etc.)
Leisure (Golf carts & trolleys, caravan & boat movers etc.)
Door operating devices
Industrial floor cleaners
Pumps & Compressors
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