The parameter setting of frequency converter is very important in the debugging process. Due to improper parameter setting, it can not meet the needs of production, resulting in the failure of starting and braking, or tripping when working. The parameters of frequency converters are different with different varieties.
General single-function control of the inverter about 50-60 parameters, multi-function control of the inverter has more than 200 parameters. But no matter how many or how few parameters you have, do you want to reset all the parameters in debugging? No, most can not change, as long as the factory value can, as long as the use of the original factory value is not appropriate to be reset, for example, external terminal operation, analog operation, base frequency, maximum frequency, upper limit frequency, lower limit frequency, start time, brake time (and mode) , thermal electronic protection, over-current protection, carrier frequency, stall protection and over-voltage protection must be adjusted. When the operation is not appropriate, then adjust the other parameters.
On-site debugging of several common problems
The starting time setting principle is suitable for short not long, the specific value is as follows.
The overcurrent setting value OC is too small and can be increased to a maximum of 150% . The experiential value is 1.5 ~ 2s/kW, the small power is larger, the larger the 30kW, the greater the value is & GT. 2s/kW. Press the Start button * RUN, the motor is stuck. The load torque is too large, the starting torque is too small (try to increase) . At this point to STOP immediately, or a long time, the motor to burn.
Because the motor does not turn is the blocking state, anti-electric heat E = 0, at this time, AC impedance value z = 0, only DC resistance is very small, then, the current is very dangerous, it is necessary to trip OC action. The setting principle of braking time should be long but not short, easy to produce over-voltage trip OE.
The free braking is suitable for the pump fan, and the fast and strong braking is easy to produce serious“Water hammer” effect. The starting frequency setting is advantageous to the acceleration starting, especially for the light load starting frequency value is big to the heavy load starting frequency value, causes the starting current to increase, in the low frequency band is easy to skip the current OC, generally starting frequency from 0 start appropriate. The setting of starting torque is beneficial to accelerating starting, especially for light load. The high starting torque of heavy load results in the increase of starting current, and it is easier to skip current OC in low frequency band, general starting torque from 0 start appropriate.
The base frequency is set to 380 V at 50 Hz, or V/F = 380/50 = 7.6. But because the heavy load (such as extruder, washing machine, dryer, mixer, mixer, dehydrator, etc.) often can not start, and other parameters often useless, then adjust the base frequency is an effective method. The 50Hz setting will be reduced to 30Hz or less. At this point, V/F & GT. 7.6, i. e. , the output voltage increases at the same frequency, especially in the low frequency band (i. e. , torque = U 2) . Therefore, the general heavy load can be better start. Overvoltage treatment during braking overvoltage is caused by short braking time and low value of braking resistance, which can be avoided by appropriately increasing the time and value of resistance.
Selection of braking method
(1) energy consumption braking. Using a common brake, energy is lost in resistance, in the form of heat loss. In the lower frequency, the brake torque is too small, to produce crawling phenomenon.
(2) DC brake. Suitable for accurate parking or parking, no crawling phenomenon, can be used in combination with energy consumption brake, generally less than 20 Hz with DC brake, < GT; 20 Hz with energy consumption brake.
(3) feedback brake. Apply ≥100kW, speed ratio d ≥10, high and low speed alternates or positive and negative rotation alternates, cycle time is also short, in this case, apply feedback brake, feedback energy can reach 20% of the motor power. More detailed analysis and parameter selection. No-load (or light-load) jump OC in no-load (or light-load) , the current is not large, should not jump OC, but the actual occurrence of such a phenomenon, the reason is often too high compensation voltage, starting torque is too large, the saturation of excitation is serious, the distortion of excitation current is serious, the peak current is too large and tripping OC, and the output value is reduced or restored or set at 0 bit.
The reason of OC jump at low frequency ≤20Hz is over compensation, high starting torque, short starting time, low protection value (including overcurrent value and stall overcurrent value) , so the base frequency can be reduced. Difficult to start, can not start the general equipment, the moment of inertia GD2 is too large, resistance torque is too large, and heavy-duty start, large fans, pumps and other similar situations often occur, the solution:
1.to reduce the base frequency;
2.Increasing the initial frequency appropriately;
3.Increase the starting torque appropriately;
4.The carrier frequency is reduced by 2.5 ~ 4kHz, and the effective torque is increased;
5.Reduce the starting time;
6.Improve the protection value;
7.The load can be changed from starting with load to no load or light load, i. e. the inlet valve can be closed to the fan. After using the frequency converter, the motor temperature rises, the vibration increases and the noise increases. The carrier frequency setting value of our company is 2.5 khz, which is lower than usual, by increasing the carrier frequency, the problem is solved.
Power on the Start button after RUN after no response
(1) the panel frequency is not set;
(2) if the motor is not moving, press“STOP” immediately and check the following:
1.Reconfirm the correctness of the line;
2.Reconfirm the identified code (especially for the part related to starting) ;
3.Whether the operation mode is set right or not;
4.Measuring input voltage, R, S, T three-phase voltage;
5.Measuring DC PN voltage value;
6.Measuring the voltage of each group of switching power supply;
7.Check the contact condition of the drive circuit plug-in;
8.Check panel circuit plug-in contact;
9.After a full inspection can be re-electrified.
Source: internet (for study only, intrusion and deletion)
