To answer the question of what a commutator engine is, you need to understand what is called an engine in general. And this is an electric machine opposite to the generator. Together, the generator and engine are called a direct current machine . It is designed to convert mechanical energy into electrical energy (that is, work as a generator) or, conversely, electrical into mechanical energy (work as an engine). If we equip a synchronous DC machine with a collector, then we get a collector motor. In the generator mode, the collector will play the role of a rectifier, in the motor mode - the frequency converter. It is thanks to him that alternating current flows through the armature winding, and direct current flows in the external circuit.
From the foregoing, it follows that the collector motor is an electric synchronous machine in which the rotor position sensor and the current switch in the windings are a brush-collector unit. Naturally, as already mentioned, he can simply become a generator.
The smallest collector motor (a few watts) consists of such mandatory parts as a three-pole rotor, sliding bearings, a manifold assembly (it also consists of two copper brush plates), a two-pole permanent magnet stator. The smallest devices of this type are used in some children's toys.
As a rule, a collector motor of higher power has a multi-pole rotor, rolling bearings, a collector assembly with four graphite brushes, and a four-pole stator with permanent magnets. It is motors of this design that are in cars, in fan drives, in cooling and ventilation systems, in pumps, wipers, and more. The main advantage of such a device as a commutator motor can be called the ease of operation, repair and manufacture.
Powerful devices (several hundred watts) contain stators with electromagnets. There are several main ways to connect such windings: sequentially to the rotor (sequential excitation, a decent maximum torque, however, fast idle speed), parallel to the rotor (the so-called parallel excitation, the advantage of which is the stability of the revolutions, but the low maximum torque should be considered disadvantages ) There are also options with mixed and with independent excitation, however, they are rarely used.
There is also a machine such as an AC commutator motor. However, it cannot be considered separately. Such a machine is usually understood as a universal commutator motor. This is such a kind of machine that runs on direct current and alternating current. Such a device has become widespread in hand-held power tools and in some household appliances, due to its small size, weight, low price, and ease of operation. Such a universal collector motor can be directly connected to the network, it has a small starting current, a simple control circuit.