As an expert in the field of electrical engineering, I have extensive experience in dealing with various types of motors and their operational nuances. When it comes to the application of AC supply to a DC motor, it's a topic that requires a nuanced understanding of the underlying principles of both AC and DC systems.

AC (Alternating Current) is a type of electrical current where the flow of electric charge periodically reverses direction. The standard frequency for AC in many countries is 50 or 60 hertz, which means the current changes direction 50 or 60 times per second. AC is the most common form of electricity for power transmission and is used to power homes and businesses.

DC (Direct Current), on the other hand, is the unidirectional flow of electric charge. In a DC system, the electrons flow in a constant direction, which makes it more suitable for certain types of applications like charging batteries, powering electronic devices, and operating DC motors.

Now, regarding the question of whether we can give an AC supply to a DC motor, the answer is technically yes, but with significant caveats and modifications. Here's a deeper look into how this can be approached:

1. **Series Connection of Armature Winding and Field Winding**: In some configurations, particularly in older or specialized DC motors, the armature and field windings might be connected in series. In this setup, if an AC supply is connected, the motor may indeed run, but it will not operate as efficiently or effectively as it would with a DC supply. The reason is that the alternating nature of the AC current will cause the magnetic field to continuously change direction, which can lead to a less consistent torque production. Moreover, the motor's speed will vary with the frequency of the AC supply, leading to a pulsating speed rather than a steady one.


2. Parallel Connection: If the armature and field windings are connected in parallel, applying an AC supply will likely result in the motor not rotating at all. This is because the torque produced during the positive half-cycle of the AC wave will be counteracted by the torque produced during the negative half-cycle. The motor will instead start to hum and vibrate, as the opposing magnetic fields will cause mechanical stress without any net rotation.

To make a DC motor run on AC, one would typically need to use a device called a rectifier. A rectifier converts the AC to DC, allowing the DC motor to operate. There are different types of rectifiers, such as full-wave rectifiers and half-wave rectifiers, which can handle the conversion with varying levels of efficiency and output DC voltage characteristics.

Additionally, the use of an inverter can also allow a DC motor to be run on AC power. An inverter is a device that can convert DC to AC and vice versa. In this case, the inverter would convert the AC power to DC, which the motor can then use.

It's important to note that running a DC motor on AC power without proper conversion and control can lead to a reduction in motor life, inefficiency, and potential safety hazards. Motors are designed to operate with specific types of current, and deviating from that can cause damage.

In conclusion, while it is possible to power a DC motor with AC supply, it requires additional components and careful consideration of the motor's design and operational requirements. It's always best to use the motor with the type of current for which it was designed to ensure optimal performance and longevity.

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When A.C. supply is given to a D.C. motor: 1)In case of Series connection of armature winding and field winding , it may run. 2)But, In case of parallel connection , it won't rotate at all and will start humming and will create vibrations, as a torque produced by positive and negative cycle will cancel out each other.read more >>