Summary:Both variable frequency motors and ordinary motors can be used as variable frequency motors, and the...
Both variable frequency motors and ordinary motors can be used as variable frequency motors, and there is not much difference in the effect between the two. How are variable frequency motors and ordinary motors usually distinguished? In fact, there are many ways to distinguish between the two.
1. Different performance
Most variable frequency motors use constant V/F control system, which is simple in structure and cheap to manufacture. Variable frequency motors also have open-loop control systems, which can meet smooth speed changes. For occasions with limited static and dynamic adjustment performance, variable-frequency motors are implemented using closed-loop control systems.
The performance of ordinary motors is mainly to consider parameters, motor overload capacity, starting performance, efficiency, power factor and so on.
2. Different speed ranges
The frequency conversion motor can adjust the speed arbitrarily within the speed regulation range.
Ordinary motors can only be used at lower frequency or higher frequency, and the range is limited, otherwise the motor will heat up and burn out.
3. Different insulation
The insulating material and thickness of the slot insulation of the frequency conversion motor are strengthened, which increases the voltage and withstands high frequencies, and also increases the electromagnetic load of the frequency conversion motor.
Ordinary motors are easy to saturate when used for frequency conversion, and will generate high excitation current. The low frequency of the inverter can reduce the damage to the insulation caused by high frequency, so the insulation of ordinary motors is low.
4. Different heat dissipation
The frequency conversion motor cooling fan and the fan core use separate wires, which greatly reduces the vibration of the motor overheating when the power is low frequency.
The cooling fan of the ordinary motor and the fan core use the same wire, so when the frequency conversion is too low, the motor may be burned out due to overheating.
5. Different service life
The inverter single and three phase motor
has more stable performance, high temperature resistance and high insulation level, so the service life of the motor is longer.
Ordinary motors have large losses caused by high-order harmonics, and poor cooling systems at low frequencies, so the service life of the motor is shorter.
The difference between variable frequency motor and ordinary motor in performance, speed range, insulation, heat dissipation and service life can be very good to distinguish between variable frequency motor and ordinary motor. The most obvious thing is that the speed of variable frequency motor can be adjusted, while the speed of ordinary motor can be adjusted. Fixed cannot be adjusted.