What Are The Characteristics And Applications Of Single-phase Series Motors And Three-phase Ac Asynchronous Motors In Aerial Work Platforms?
Aerial work platforms commonly use two types of motors: single-phase series-excited motors and three-phase AC asynchronous motors. Single-phase series motors are also known as universal motors and are AC-DC motors that are connected in series with both the armature winding and the field winding. They are widely used in daily life, such as in electric tools, and have high speed, small size, large starting torque, and adjustable speed. Single-phase series motors are commonly used in liquid-driven scissors and electric-drive scissors to provide enough energy for load lifting, as they can provide greater power. However, it is inconvenient to control the commutation of series motors. Therefore, they are usually used with a motor driver that is voltage-regulated.
Three-phase AC asynchronous motors, on the other hand, are based on the force generated by the interaction of the stator's rotating magnetic field and the rotor current to make the motor rotate. They have simple structure, reliable operation, low price, and strong overload capacity, making them widely used. The mechanical characteristic is the main characteristic of three-phase AC asynchronous motors. At the beginning of starting, the starting torque is greater than the resistance torque to make the motor rotate. As the speed increases, the electromagnetic torque will always increase until it reaches a certain value, and it is in a stable state. Three-phase AC asynchronous motors are commonly used in electric drive off-road scissors and have become the first choice for vehicle power. The whole machine power supply is DC, but the motor is driven by a motor driver that is voltage-regulated.
The three-phase AC asynchronous motor is a widely used motor in the electric vehicle industry, including aerial work platforms. It has several advantages, such as simple structure, reliable operation, low price, and strong overload capacity. The mechanical characteristic of the three-phase AC asynchronous motor is its main feature. It refers to the relationship between the speed and the electromagnetic torque.
During starting, the starting torque of the motor is greater than the resistance torque, making the motor rotate. As the speed increases, the electromagnetic torque increases during acceleration. The BC segment quickly passes through as the speed increases, and then the AB segment. This segment will decrease as the speed increases. When the speed reaches a certain value, the electromagnetic torque is equal to the force against the torque, and the speed does not rise anymore, and it is in a stable state. Therefore, the mechanical characteristics of the AC asynchronous motor have two regions, one is the BC unstable region during the acceleration process, and the other is the AB segment stable region. Motors generally work in the stable zone.
When using an AC motor to drive an aerial work platform, it is important to note that the power supply of the entire machine is DC. To drive the AC motor, a motor controller is required, which can convert the DC power supply to AC power for the motor. The motor controller usually consists of an inverter, a rectifier, a control unit, and a filter unit.
The inverter converts the DC power supply to AC power by changing the frequency and voltage. The rectifier converts the AC power generated by the motor into DC power and sends it back to the power supply. The control unit is responsible for monitoring the motor's speed and other parameters and adjusting the frequency and voltage of the AC power supplied to the motor to control its speed. The filter unit is used to filter out high-frequency noise generated by the inverter and protect the motor.
Compared to DC motors and single-phase series motors, three-phase AC asynchronous motors have higher efficiency, better performance, and lower maintenance requirements. This makes them an ideal choice for electric drive aerial work platforms that require high efficiency, stability, and reliability. With the development of electrification in the aerial work platform industry, it is expected that the application of AC motors will become more widespread.
For more information about the aerial work platforms, welcome to contact us.
Shandong Cathay Machinery Co., Ltd
www.cathaylift.com
Email:sales@cathaylift.com
