Wuxi Lanhai Electric Motor Co.,Ltd
Add: 4#, Tianshi Road Shitangwan Town, Wuxi, Jiangsu, China
Motor properties of engine and brake
1, the Motor properties of engine
The Motor properties of engine refers to the speed of the motor n and the relationship between the electromagnetic torque Tem. Due to the speed of n and slip S has certain corresponding relationship, so the Motor properties are also commonly used Tem = f (S) in the form of representation. Electromagnetic torque expression of engine has three forms, namely physical expression, parameter expression and practical expressions. Physical expression reflects the physical essence of asynchronous motor electromagnetic torque generated, the electromagnetic torque is made up of the main magnetic flux and rotor active current interaction. Parameter expression reflects the electromagnetic torque and power supply and motor parameters, the relationship between the use of this type can be easily analyzed the influence of the parameters of electromagnetic torque and the influence of various kinds of man-made features. Practical expression is simple, easy to remember, it is often adopt the form of engineering calculation.
Maximum torque of the motor and the torque is reflected the overload capacity of the motor and two important indexes of startup performance, the greater the maximum torque and starting torque, motor overload ability is stronger, the better starting performance.
The Motor properties is a nonlinear curve of engine, in general, with maximum torque (or critical slip) as the cut-off point, its linear segment is stable operation area, and nonlinear for unstable operation area. Inherent Motor properties of the linear segment belong to hard, the speed of the rated working point is slightly lower than the synchronous speed. Artificial Motor characteristic curve of the shape parameter expression analysis are available, and analysis the key to seize the maximum torque, critical slip and starting torque of the three changing with the parameters.
2, engine braking
There are three types of engine braking condition: energy consumption braking, reverse connect braking (power two opposite and pour la inversion) and regenerative braking. These three braking state of Motor characteristic curve, the relationship between the energy conversion and use, the characteristics are similar to dc motor braking state.
The rated torque of engine said motor output shaft torque measurement under the rated conditions. Force and torque arm or the product of the couple arm, in the international system of units (SI), the measuring unit of torque for Newton? M (N, m), engineering technology was also used in kilograms force? M as the measuring unit of torque, etc. The motor output shaft torque is equal to the rotor of the output Motor power divided by the angular velocity of the Motor rotor. Dc motor TK = 9.55 KeIK locked-rotor torque calculation formula.
Can know M ∝ U12 torque is directly proportional to the square of the power supply voltage, a normal input voltage when load torque is the M2, the drop in voltage electromagnetic torque M decreased a lot; Because M2 constant, M less than M2 balance is damaged, led to a decline in motor speed, the slip S rise; It caused the change of the rotor voltage balance equation, the rotor current I2 rise. Is the stator current I1 will increase (by the relationship between transformer can know); I2 increase is also at the same time give out a torque of the motor shaft M back again, until it is equal and M2. At this moment motor speed and tending to new stable value.