What is the application of frequency control? What are the benefits?
It can be applied to rotating machinery with speed regulation requirements.
What are the benefits of frequency control?
Before the implementation of variable frequency speed regulation (the theory has already been realized, but the real implementation is after the invention of power electronic devices). The disadvantages of traditional speed regulation using DC and DC speed regulation are:
1. DC motor has a complicated structure and high maintenance cost
2. Due to the presence of the commutator, there is not much room for DC motor power to rise.
Therefore, the advantages of frequency control are:
1. It can make the AC motor get the same speed regulation performance as the DC speed regulation.
2. The AC squirrel cage asynchronous motor is easy to maintain.
3. There is no limit to the commutator for AC motor power.
5, using 100KVA transformer to supply the total power of 100kW appliances (maximum 37kw) is enough?
How much load can a 100KVA transformer carry? Look at the calculation formula below to know
P = capacity * power factor * 80% = 100 * 0.9 * 80% = 72KW, generally overloaded 20% operation for 1 hour is allowed, so enough.
Mainly see the total current is not super, 100KVA transformer high voltage current is 5.8A, low voltage current is 150A, even if the occasional super does not matter, mainly depends on the temperature rise not more than 55 degrees. The temperature rise is equal to the actual temperature minus the ambient temperature.
6, how to measure the insulation resistance of the motor?
If it is a three-phase AC motor, measure the phase-to-phase and ground-to-ground insulation resistance of the three-phase winding of the motor.
If it is a DC motor, measure the motor armature winding to ground, the series winding to the ground, and the excitation winding to ground, the series winding to the other. Select the corresponding shaker according to the voltage level of the motor to be tested.
Measurement steps:
---cut off the power
---Discharge to ground
--- If it is a three-phase AC motor to open the center point (if you can)
--- If it is a DC motor, lift the brush.
---Use the shaking table to detect the insulation resistance between phases and ground
---Discharge to ground
---Recovery line
--- Record the insulation resistance, and the ambient temperature is on the case.
If you want to buy a food processing machine, please pay attention to big power motor.
