Advantages of a Miniature DC Motor
The primary materials in a bldc motor are metals such as copper, tin and iron. These first-source metals offer exceptional power density, excellent speed control and position control.
These features make the bldc motor ideal for powered surgical hand tools used in minimally invasive surgeries. The motor can operate reliably in autoclave environments while delivering a wide range of torque values and speeds.
High Power Density
Power density is an important factor in selecting a motor for any application. It is the ratio of mechanical power (torque) to electrical power (current and voltage). BLDC motors have high power densities that allow them to deliver more torque in smaller sizes than other motor types.
The main components of a BLDC motor are the stator and the rotor, which contains permanent magnets. The stator has coils that generate a magnetic field when an electric current passes through them. The rotor rotates when the stator’s magnetic fields align with its own. The motor controller is responsible for detecting the position of the rotor, which can be done by using Hall sensors implanted in the stator. The Hall sensor produces low and high signals to indicate the rotor’s location.
BLDC motors do not use brushes to commutate the current, so there are no sparks when turning the rotor. This reduces the amount of heat generated and the electrical noise that is associated with brushed motors.
Small BLDC motors with integrated control technology are ideal for applications that require high speed and low inertia. For example, ResMax BLDC motors from Allied Motion are designed specifically to power ventilators. They can miniature bldc motor reach speeds up to 90,000 revolutions per minute and have a minimal mechanical time constant of 4ms. This makes them perfect for medical devices that need to be sterilized.
Long Lifespan
While brushed motors continue to be used in a variety of devices, the BLDC has quickly gained popularity in many modern gadgets and technology owing to its higher power efficiency and longer lifespan. Unlike traditional DC motors that utilize brushes, a BLDC doesn’t have to contend with friction and wear which increases the lifespan of the motor. It is also important to choose high quality components in the manufacture of the rotor, stator and copper windings which contribute to the longevity of the motor.
Choosing a multi-pole encapsulated core and high-performance rare earth neodymium magnets helps to lower the cogging torque magnitude and improve the radial symmetry of magnetic radial forces. In addition, a symmetrical winding pattern and high LCW or Lowest Common Multiple will reduce unbalanced magnetic fields and increase the BLDC’s power-to-weight ratio.
Regular lubrication is also important to reduce friction and prolong the life of a bldc motor. Always use manufacturer-recommended lubricants and follow the specified lubrication schedule. A well-maintained bldc motor will operate at peak performance for the life of the product.
Precise Speed Control
The high speed performance of a miniature bldc motor is attributed to its very low mechanical time constant (MTC). The motors produce very little inertia and can achieve speeds up to 90,000 revolutions per minute. This allows for a very high control resolution without the pulsing and other hysterese phenomena associated with simple brushed DC motors.
In closed loop speed control the controller continuously monitors the actual motor speed, either by sensor feedback (like encoders or hall sensors) or by measuring the actual back EMF of the motor. This information is compared to the desired setpoint and the voltage or current are adjusted accordingly.
Typically the control unit generates controlling pulses, also known as back EMF signals, via a frequency-controlled inverter. This pulsating input current causes ripples miniature bldc motor wholesale in the motor’s torque. To eliminate these problems, advanced FOC controllers have special features which ‘learn’ the motor’s characteristics and adjust their output current to a minimum of ripples or hysteresis.
In this way, a precise torque control can be achieved without the need for complex position-based feedback. As a result, the motor’s performance is very close to the ideal reference value – even if the load torque increases. This is very important for many applications, e.g. in the automotive industry for achieving smooth and powerful motion of vehicles or in the oil & gas sector for pipeline inspection robots.
Low Noise
BLDC motors do not use carbon brushes or copper commutator, which wear down and generate electrical noise. Instead, they have a position sensor (such as an encoder, resolver or Hall element/Hall effect IC) to detect the rotational position of the rotor and switch ON and OFF current to the stator coils to control the speed of the motor. This eliminates the commutation abrasion and electric noise and extends the lifespan of the motor.
The internal design of a miniature bldc motor determines its performance, so it’s important to understand what’s inside before selecting the right one for your application. For example, look for a model that has a low core loss to maximize power output over a broad speed range. You should also choose a motor with high efficiency ratings to minimize energy losses and prolong battery life.
BLDC motors are ideal for robotic applications, but they can also be used for more traditional purposes. For example, they can be incorporated into powered surgical hand tools that can be sterilized in an autoclave. This allows surgeons to use highly precise, ergonomically designed tools that are easy on the hands and provide great power in a small package.