What motors are in hair dryers and what are their differences

Almost every hair dryer guide mentions that there are different types of motors in them. But almost nowhere is it written how exactly they differ and why one type of motor is better than another. How the motors of modern hair dryers are arranged, what are their advantages and disadvantages – in this article.

DC motors

DC – Direct Current – “direct current” – collector DC motors.

In the collector motor, the windings are located on a rotating rotor, the windings are switched using a brush assembly. The brushes are in contact with a winding that is in a magnetic field from the stator magnets, an EMF (electromotive force) arises in the winding when current flows, the rotor is displaced, turning the collector and closing the next winding.

Hair dryers use low voltage DC motors – usually 12, 24 and 36 volts. With a higher voltage, it is necessary to increase the distance between the collector contacts to prevent sparking, and this increases the size of the device. To reduce the voltage, one of the heater coils is used. Further, the reduced voltage is rectified by a diode bridge and goes to the motor.

Hair dryer DEXP BA-200 pink 730 *
Hair dryer BRAYER 3040BR-RD black/red
1 399 *
Advantages
Simplicity and low cost of construction.
Compact and light weight.
High turnover. This allows you to use a small, lightweight impeller to create the required airflow, which reduces the weight of the entire hair dryer as a whole.
Easy speed control. The rotation speed of the collector motor is controlled by changing the voltage. It is possible both stepwise regulation (usually 2-3 speeds) with the help of resistors, and smooth – with the help of a variable resistor. The components are cheap and have almost no effect on the final price of the device.
The compact closed design of the DC motors makes it impossible to use the hair dryer without interruptions to cool down.

Pardot-Consultant
DES-1111
MB-260
700-760
C_C4H510_01
1Z0-1047-21
PGCES-02
700-846
NSE5_FAZ-6.4
HPE6-A78
CAS-PA
H12-723
H12-722

disadvantages
Small resource. The rubbing elements of the engine – brushes and commutator – are already subject to wear, and at high temperatures the situation only gets worse. As a result, the MTBF for commutator motors is 500–1500 hours.
The cheapest models do not have cold air blowing. If one of the heating coils of the heater is used to reduce the voltage, then it is impossible to turn it off and the air will always be warm, and even hot at low speed.
Impossibility of continuous work. Inexpensive hair dryer DC motors often have a compact, enclosed design. Air blowing is not enough to remove the heat generated inside the electric motor, so it must be periodically allowed to cool.
A disadvantage not related to the design of the motor, but often present in hair dryers with a DC motor: low power. Since a DC motor is usually installed in inexpensive models, many manufacturers put inexpensive low-power motors in order to further reduce the cost, overestimating their characteristics. For example, adding to the engine power the power of the ballast coil, which reduces the voltage from 220 V to the required one.
AC motors

AC – Alternating Сurrent – “Alternating current” – in relation to hair dryers, an alternating current collector motor.

The designs of AC and DC commutator motors differ only in that the former has excitation windings instead of permanent magnets on the stator. Due to the series connection of the armature and stator windings, the change of poles in them occurs simultaneously, so that the principle of operation of the motor is the same as that of a DC motor.

AC motor with open design, thanks to which heat dissipation remains at a high level.

Advantages
It does not require a ballast coil and a rectifier, it can be powered directly from the mains. As a result, cold air blowing is possible.
Possibility of continuous operation. AC motors installed in hair dryers often have an open design that provides good heat dissipation.
Low starting current. This reduces harmful loads during switching on and increases the life of the engine. AC motors have 500–2500 hours of MTBF.

Hair dryer Philips DryCare BHD272/00 black/blue 3 499 *
disadvantages
More complex regulation. If you reduce the speed by lowering the voltage, at 230 V a lot of heat will be generated on the resistor. Therefore, hair dryers use a thyristor speed control circuit. It is quite simple and inexpensive, but still more complicated than the one used in hair dryers with a DC motor.
Greater weight and dimensions. High voltage requires an increase in wire cross-sections and pad thicknesses.
The price is higher than DC motors.
EC Motors (BLDC)

EC – Electronically Commutated – “Electronically Commutated” or BrushLess DC electric – “Brushless DC” – brushless DC motor.

In the EC motor, the electrical windings are located on the stator, and powerful neodymium magnets are fixed on the armature. EMF occurs when the armature poles of the same name and the stator windings are opposite each other. The armature is displaced, and the winding is switched to the next one by an electronic controller, which also performs the function of a speed controller. The position of the rotor is monitored by a Hall sensor.

Hair dryer Valera Unlimited PRO 5.0 RC black 13 299 *
Advantages
The absence of a collector unit and the absence of starting currents significantly increase the life of the engine. EC motors have up to 10,000 hours of MTBF.
Compactness. With the same power, the EC motor will be smaller than the AC motor.
Minimum heat dissipation. This ensures long-term operation of the hair dryer without overheating and makes it possible to blow cold air at the same temperature as in the room. For example, the AC motor heats up more (35–75ºС) and will heat the passing air at least a little.
Minimum noise and vibration levels.
Precise speed control throughout the entire range.

Hair dryer Parlux 0901-Alyon black 12 299 *
disadvantages
High price. Rather complicated controller electronics and the use of expensive permanent magnets make the price of this type of motors maximum. Therefore, EC motors are installed only in expensive professional models of hair dryers.

What is the result
For a household hair dryer, the capabilities of a DC motor will be enough – it does not need long work, and its low weight and dimensions will be an advantage if you take a hair dryer with you on a trip. For professionals, the DC motor is no longer suitable and you should choose among hair dryers with AC and EC motors. The latter are much more expensive, but they also have a higher resource.