Operation of the Vector Universal VFD LSD-B7000 at will during use will not only fail to perform its excellent functions, but may also cause damage to the inverter and its equipment, and may cause interference. Therefore, the following matters should be paid attention to during use.
The inverter must be selected correctly;
(1) Read the product manual carefully, and connect, install and use according to the requirements of the manual;
(2) The inverter equipment should have a reliable grounding, which can not only effectively suppress the radio frequency interference, but also prevent the inverter from electric shock;
(3) When the inverter is used to control the motor speed, the temperature rise and noise of the motor will be higher than the grid power (power frequency); due to the low speed of the motor fan blades, attention should be paid to ventilation and cooling at low speed, and the load of the motor should be appropriately reduced to avoid The temperature rise of the motor exceeds the allowable value;
(3) The impedance of the power line should not be too small. The inverter is connected to the voltage grid. When the capacity of the distribution transformer is greater than 500kVA or 10 times the capacity of the inverter, or when the inverter is connected close to the distribution transformer, the circuit impedance is small, which will cause a large surge to the inverter and damage the inverter. rectifier element. When the line impedance is too small, an AC reactor should be installed between the grid and the inverter;
(4) The impedance of the power cord should not be too small. The inverter is connected to the voltage grid. When the capacity of the distribution transformer is greater than 500kVA or 10 times the capacity of the inverter, or when the inverter is connected close to the distribution transformer, the circuit impedance is small, which will cause a large surge to the inverter and damage the inverter. rectifier element. When the line impedance is too small, an AC reactor should be installed between the grid and the inverter;
(5) Do not install an excessively large capacitor on the incoming side due to improving the power factor, nor install a capacitor between the motor and the inverter for this reason, otherwise the line impedance will be reduced, resulting in overcurrent and damage to the inverter;
(6) The outlet side of the inverter cannot be connected in parallel with the compensation capacitor, nor can it be connected in parallel with the capacitor to reduce the high-order harmonics of the output voltage of the inverter, otherwise the inverter may be damaged. In order to reduce harmonics, reactors can be connected in series;
(7) The start and stop of the motor speed-regulated by the inverter cannot be directly operated by the circuit breaker and the contactor, but should be operated by the control terminals of the inverter, otherwise the inverter will be out of control and may cause serious damage. as a result of;
(8) It is generally not advisable to install an AC contactor between the inverter and the motor, so as to avoid overvoltage between the interruptions and damage the inverter. If installation is required, the output contactor should be closed first before the inverter runs;
(9) For the occasions where the inverter drives the ordinary motor for constant torque operation, long-term low-speed operation should be avoided as much as possible, otherwise the heat dissipation effect of the motor will become poor and the heat will be serious. If you need to run at low speed and constant torque for a long time, you must choose a variable frequency motor;
(10) For the occasion of lifting the load and frequent starting and stopping, there will be a large torque, and it is necessary to select an appropriate braking resistor, otherwise the inverter will often trip due to overcurrent or overvoltage faults;
(11) When the motor has another brake, the inverter should work in the free stop mode, and the brake action signal will not be sent until the inverter sends the stop command;
(12) The resistance of the external braking resistor of the inverter cannot be less than the requirement of the braking resistor allowed by the inverter. On the premise of meeting the braking requirements, the braking resistor should be larger. Do not directly short-circuit the terminals that should be connected to the braking resistor, otherwise, a short-circuit accident will occur through the switch tube during braking;
(13) When the inverter is connected to the motor, it is not allowed to use a megohmmeter to measure the insulation resistance of the motor, otherwise, the high voltage output by the megohmmeter will damage the inverter;
(14) Correctly handle the problem of acceleration and deceleration. If the acceleration and deceleration time set by the inverter is too short, it is easy to suffer from “electric shock” and may damage the inverter. Therefore, when using the inverter, the acceleration and deceleration time should be extended as far as possible under the premise of the load equipment.
(15) If the load is heavy, the acceleration and deceleration time should be increased; otherwise, the acceleration and deceleration time can be appropriately reduced. If the load equipment needs to accelerate and decelerate in a short time, it must be considered to increase the capacity of the inverter, so as to avoid too much current and exceed the rated current of the inverter. If the load equipment needs a very short acceleration and deceleration time (for example, within 1s), the braking system should be considered on the inverter. Generally, larger-capacity inverters are equipped with a braking system;
(16) Avoid the mechanical resonance point of the load equipment. Because the motor is within a certain frequency range, it may encounter the mechanical resonance point of the equipment, resulting in mechanical resonance and affecting the operation of the system. To this end, it is necessary to set the jump frequency (or avoidance frequency) for the inverter, and jump over (avoid) the frequency to avoid the resonance point;
(17) Before the motor is used for the first time or connected to the inverter after being placed for a long time, the insulation resistance of the motor must be measured (with a 500V or 1000V megger, the measurement value should not be less than 5M ohms). If the insulation resistance is too low, the inverter will be damaged;
(18) The inverter should be installed vertically with ventilation space, and the ambient temperature should not exceed 40℃;
(19) Anti-interference measures must be taken to prevent the inverter from being disturbed and affecting its normal operation, or the high-order harmonics generated by the inverter interfere with the normal operation of other electronic equipment;
(20) Pay attention to the thermal protection of the motor. If the motor and the inverter capacity are adapted, the thermal protection inside the inverter can effectively protect the motor. If the two capacities do not match, the protection value must be adjusted or other protection measures must be taken to ensure the safe operation of the motor.
(21) The electronic thermal protection value of the inverter (motor overload detection) can be set within the range of 25%-105% of the rated current of the inverter.
The frequency conversion speed regulating air compressor has reliable energy-saving transformation technology, simple installation, convenient operation, low failure rate, and considerable economic benefits, which is worthy of vigorous promotion and application. However, it is also necessary to focus on mastering the relevant knowledge in the technical transformation and use of compressor inverters to avoid unnecessary economic losses.
Post time: Feb-21-2022