All the motors in mechanical devices including household appliances can generally fall into three categories depending on the current they use. We have AC motors, DC motors, and universal motors. Each motor will have its unique features that set it apart from the rest, and it will also have different capabilities. To learn more about the different motors, it is better to compare two types of motors rather than all three together. This article will therefore focus on ac series motor vs universal motor.
In essence, an AC series motor is a modified DC series motor. If you tried to run a DC series motor on AC power supply, you would experience numerous problems. For one, it would be prone to overheating, and it would also not generate enough power. For this reason, the DC series motor is modified so that it can use AC supply. In the AC series motor, the armature and field are still wound and interconnected just as in the DC series motor. Its magnetic circuit is, however, laminated, a low-reluctance magnetic circuit is used, and high-resistance leads are used to connect the coils to the commutator. With these changes, the AC series motor can now use single phase AC supply.
The universal motor, on the other hand, can run on both single-phase AC and DC supply hence the name universal. It is also highly modified so that it can run on both types of current. Given the same voltage, a universal motor will have higher speeds on DC supply than on AC supply because of the voltage drop that exists on AC supply. The interesting thing is that whether the universal motor is connected to AC or DC supply, it will still work as a DC series motor due to its design and modifications. It has low speed at full load and high speed at low load.
When it comes to application and advantages, there are some differences in the AC series motor vs universal motor. The universal motor is the most preferred motor for home appliances such as blenders, food mixers, vacuum cleaners sewing machines and electric shavers. Commercially it is common in drills and other heavy machinery. The ac series motor has the benefit of being more efficient, reliable and durable than the universal motor. This is because the brush in the universal motor is prone to wear and tear and sparking can cause damage to its commutator.