The main principle of the Direct Current Permanent Magnet Motor is when the current carrying conductor located inside the field of the magnet. So there is a mechanical force created in the conductor. So in direct current motor magnetic force must establish. These magnetic force can create by mainly two ways such as electromagnetically or by using a permanent magnet. In our previous articles, we have discussed on several types of direct current motors which work under the principal of the electromagnetic effect. Today we are a plan to discuss how dc motor can work by using permanent magnet method.
Speed Controlling Methods
Since the permanent magnet is stationary on the motor it’s impossible to control the field of it. Due to this reason, the speed control of this DC permanent magnet motors is quite difficult.
Since the speed cannot control by the field circuit so armature based speed controlling methods are used to control the speed of permanent magnet direct current motors.
Following are several speed controlling methods widely used in this kind of motors.
- Armature voltage controlling method
- armature rheostat controlling method
- chopper controlling methods
Construction of direct current permanent magnet motor
As we explained earlier the permanent magnets are used to create rotation under this direct current permanent magnet motor.
Compare with electromagnetic motors the construction of this direct current motor is quite simple.
Construction of the permanent magnet motor consists
two parts which are armature and stator. Stator part of the motor consists the permanent magnet. The armature part consists the conductor windings and commutator. This armature conductor coil is also insulted by laminated steel.
Applications of direct current permanent magnet motor
this permanent magnet direct current motors are widely used for low power economical applications such as followings.
- In automobile industry
- washer and blowers
- air conditioners
- industrial heaters
- widely use for electrical toys
- Computer-based drivers
- Use in portable vacuum cleaners and domestic food mixers
Advantages of Permanent Magnet DC Motors
- Compare to electromagnetic motors it’s economically cheaper
- The physical size of the permanent magnet DC motors is small
- Efficiency of this motor is higher
- Simple construction
- due to the small size, the manufacturing cost of this motor is low
- No need to provide electrical field externally
- Not required any field windings
- There is only one winding inside this motor so it’s more economical.
Disadvantages of Permanent Magnet DC Motors
- Speed controlling of this Permanent magnet DC motors are difficult
- Unable to add external current to reduce the armature reaction.
- Difficult to use large industries.
- If the magnets get demagnetization it can absorb high armature current.
Normally this type of dc motors work under low voltage levels so direct current supply can provide through batteries. Hope that you have some good understanding on direct current permanent magnet motors.