Surveillance camera DC brushless motor for Photography Equipment

Surveillance cameras and photography equipment require precise movements to capture high-quality images and footage. A DC brushless motor is the ideal solution, offering quick response times and quiet operation.A sensor translates encoder information into incremental position signals communicated over long cables in quadrature form (sine + cosine). A drive then uses the PWM technique to chop current in order to optimally energize each phase as a function of rotor position.One of the most important features of a security camera is the motor that drives it. It won’t matter how good the video quality is if the motor fails and stops working.The most common style of motor used in surveillance cameras is a brushed DC motor. These use two stationary metallic brushes that contact different segments of the commutator to transfer current and create rotation. These motors generate a lot of heat, wear out fast, and require regular maintenance.

A more reliable option is a brushless DC motor. Generally with three winding phases, these are electronically commutated. The electronics detect the zero-crossing of the phase voltages to determine rotor position and energize the phases as a function of this position. This eliminates the need for Hall sensors, simplifies wiring and adds reliability. BLDC motors also have a longer lifespan than brushed DC motors.Brushless motors consume less power than brushed motors to achieve the same output, which is especially important in surveillance equipment where the ability to conserve battery power is critical. These motors also have fewer moving parts than brushed motors, which reduces the likelihood of mechanical failures and maintenance needs and gives them a longer lifespan.A brushless motor can use the back EMF generated by its coils to monitor rotor position and speed, eliminating the need for sensors. This makes it possible to use a properly designed open loop control system without any sensors in the motor itself, further improving efficiency and reliability.

These motors are identified by their diameter and length in a coding scheme, including B for slotted (high performance-critical surgical power devices), BH for linear, and EC for industrial automation equipment.DC brushless motors have the ability to produce high torque which can be used to lift cameras with heavy payloads or move them around challenging locations. They also have a longer lifespan than brushed motors, reducing the need for maintenance and repairs.Unlike brush DC motors where the commutation is achieved mechanically by brushes squeezing the commutator rings, brushless dc motors are electronically commutated. They use hall sensors to detect the position of the rotor magnet (blue arrow) and electronic switches, called an H-bridge (a group of 6 transistors), to energize the phases of the motor in a sequence that will best maintain the orientation of the stator and rotor magnetic fields.

This makes them better suited for applications requiring precision and control, such as positioning systems like PTZ cameras (Figure 4), stage lighting equipment or industrial robots. This motor type is also often referred to as a servo drive.Surveillance equipment, such as pan-tilt-zoom (PTZ) cameras, and photography equipment, such as gimbals, require precise movements to capture accurate images and footage. They also need to operate quietly, as any noise could alert or disturb subjects. Using a brushless motor can help to ensure smooth and silent movement, making it an ideal choice for these types of applications.Unlike brushed motors, which use brushes that create sparks and noise, a brushless DC motor is electrically commutated. This allows for quiet operation, as there are no mechanical components involved.Moreover, sensorless commutation is possible by using a unipolar pulse width modulation (PWM) with the right terminal voltage sensing scheme. This can overcome the sensitivity to switching noise of the traditional ZCD method and achieve good motor performance over a wide speed range.