Selection of inverter braking method

(1) Energy consumption braking. With general braking, the energy is dissipated in the resistance and is lost in the form of heat. At lower frequencies, the braking torque is too small to cause creep.

(2) DC braking. Applicable for precise parking or parking, no creeping, can be used in combination with energy braking, generally with DC braking at ≤20Hz, and with energy consumption at >20Hz.

(3) Feedback brake. Applicable ≥100kW, speed ratio D≥10, alternating high and low speed or alternating positive and negative, the cycle time is also short. In this case, feedback braking is applied, and the feedback power can reach 20% of the motor power. More specific details analysis and parameter selection. No-load (or light-load) jump OC is reasonable when no-load (or light load), the current is not large, should not jump OC, but this phenomenon has actually occurred, the reason is often the compensation voltage is too high, starting torque If it is too large, the excitation saturation will be severe, causing the excitation current to be severely distorted, causing the spike current to be too large and tripping OC, and appropriately reducing or restoring the factory value or placing it at the 0 position.

The reason for jumping OC at low frequency ≤20Hz at startup is due to over-compensation, large starting torque, short starting time, too small protection value (including overcurrent value and stall overcurrent value), and the base frequency can be reduced. Difficult to start, can not start the general equipment, the moment of inertia GD2 is too large, the resistance torque is too large, and heavy load start, large fans, pumps and other similar situations often occur, the solution:

1 reduce the substrate frequency;

2 appropriately increase the starting frequency;

3 Appropriately increase the starting torque;

4 reduce the carrier frequency value of 2.5 ~ 4kHz, increase the effective torque value;

5 reduce the starting time;

6 increase the protection value;

7 The load is converted from no-load start to no-load or light load, that is, the small inlet valve can be closed to the fan. After using the inverter, the temperature rise of the motor is increased, the vibration is increased, and the noise is increased. Our carrier frequency setting value is 2.5 kHz, which is lower than the usual one. The purpose is to use safety from the perspective, but it is more common to reflect the above three problems. After increasing the carrier frequency value, the problem is solved.

After power transmission, press the start button RUN and no response

(1) The panel frequency is not set;

(2) The motor does not move. In this case, immediately press “STOP STOP” and check the following items:

1 Confirm the correctness of the line again;

2 reconfirm the determined code (especially for the part related to the start);

3 Run mode setting is correct;

4 measuring input voltage, R, S, T three-phase voltage;

5 measuring the DC PN voltage value;

6 measuring the voltage value of each group of switching power supplies;

7 check the contact of the driver circuit plug-in;

8 Check the contact status of the panel circuit plug-in;

9 After a full inspection, the power can be turned on again.