Whenever the inverter is down due to a problem, a problem code will appear. The most common causes are overcurrent, overvoltage, inverter temperature, etc. It's a good idea to find an explanatory book with specific questions to be asked about.
1. Overload trip (OL)
Maintenance features for overload tripping
1. Maintenance objectives of OL tripping
OL is a code for an overload of a motor, and its maintenance target is the motor. In most cases, the detection point is in the output circuit of the drive.
2. Features of motor overload maintenance
(1) The size of the current
A sign of motor overload is that the output current of the inverter exceeds the additional current of the motor. However, the additional current that has not exceeded the inverter has not yet been exceeded, that is, it is within the promised range of the inverter.
(2) Maintenance moments
According to the anti-time limit rule. That is, the more overloads, the shorter the maintenance period. Some inverter rules: when IM=125%IMN, trip after 4min; When IM=165%IMN, it will trip after 1min.
Possible cause of overload tripping
1. The load is too heavy
The load on the motor is too heavy, or in other words, the resistance torque of the production machinery exceeds the additional torque of the motor.
This is the real overload and the most common overload phenomenon, so when the trip code of the inverter appears as 'OL', the first thing that should be looked at is the weight of the load.
2. Use improper overload
For example, the operating frequency is advanced to exceed the extra frequency of the motor, and when the motor runs above the extra frequency, it will enter the constant power operation area, and its useful torque decreases with the rise of the frequency, and when the useful torque is less than the load torque, the motor is overloaded.
3. Improper overload of function preset
For example, a production machine is in a light load situation, the operating frequency is very low, and the torque progress (U/f ratio) is preset too large, resulting in "overload" due to the saturation of the magnetic circuit during low-frequency operation.
4. The voltage on the motor side is too low
(1) The voltage drop of the line is too large
Because the output voltage of the inverter is already low when running at low frequency, if the distance between the motor and the inverter is large, and the wire diameter of the connecting line is thin, the line voltage drop may cause the lack of voltage on the motor side.
(2) Lack of torque progress
In U/f operation, the output voltage of the inverter at low frequencies depends on the torque progression. When the torque progress is small, it will lead to a lack of voltage obtained by the motor.
The relevant code for overload tripping
1. Code DEV
The meaning is that the deterioration is too great. When the asynchronous motor is running, the size of the slip directly reflects the weight of the load. So, when the inverter finds that the slip is too large, it will trip.
2. Code VAE
The meaning is that the capacity of the inverter is not selected properly. Many users choose the inverter according to the 'distribution motor capacity' in the inverter description book. Actually, this is only true about successive constant loads. While most of the loads are variable loads or intermittent loads, the motor is promised to be overloaded for a short time. For this kind of load, when selecting the inverter, the capacity of the inverter should be appropriately increased.
3. Code LF
The meaning is that the three-phase output current of the inverter is unbalanced.
On the one hand, when the three-phase current of the motor is unbalanced, it is clear that there must be a problem in the output circuit of the inverter, and maintenance should be carried out. Therefore, some inverters are set up with three-phase current unbalanced maintenance.
4. Code JC
The meaning is that the current sampling is faulty. For example, the measured output current of a frequency converter is 45A, but the display screen is 88.6A, indicating that there is a problem with the current sampling circuit inside the frequency converter.
5. Code SP
The meaning is that the output of the inverter is out of phase.
When the output of the inverter is out of phase, the motor is in a single-phase operation condition, the current must be large, and the inverter will be maintained immediately.
6. Code GF
The meaning is that the output side of the inverter is grounded.
The inverter has the function of detecting the current to the ground of the output terminal, and if the measured current to the ground exceeds 50% of the additional current of the inverter, it is considered that the output side of the inverter is now grounded. There are two conditions: either the internal insulation of the motor is broken; or the insulation of the transmission line.
2. Overcurrent Trip (OC)
Maintenance features for overcurrent tripping
1. Maintenance objectives of overcurrent
In the frequency conversion speed regulation system, there are two devices: the frequency converter and the motor. The degree of tolerance to overcurrent is not the same. Planners of the production machinery decide on the capacity of the electric motor according to the heat criterion. That is to say, as long as the temperature rise of the motor does not exceed the promised value, the short-term overload is promised, while the inverter does not promise. Therefore, when carrying out maintenance, the requirements are considered separately.
For this reason, the inverter is additionally equipped with an overcurrent maintenance function, and its maintenance target is the inverter, to be precise, the maintenance of the inverter device in the inverter. Generally, when the output current exceeds 200% of the additional current of the inverter, the inverter undergoes overcurrent maintenance.
2. Detection of overcurrent
Since the maintenance target is the inverter device, the time of overcurrent is not delayed, and maintenance must be carried out promptly. Generally, the overcurrent signal is obtained by passing through the voltage drop of the inverter device. Taking IGBT as an example, the tube voltage drop is generally below 3V during normal operation. If the voltage drop of the tube exceeds 7V, it is considered to be an overcurrent. Because overcurrent can easily damage the inverter, in most cases, the overcurrent is maintained directly by the drive circuit.
Overcurrent during operation
Some inverters only show the "OC" code abstractly after the overcurrent trips. Some inverters use "OC" as the code for "overcurrent in operation", and have different codes for other different reasons, such as the following:
1. Code OCN
The meaning is overcurrent in operation. Here are two examples:
(1) The load is stuck
During the operation of the production machinery, a certain part was suddenly stuck, and the motor was blocked. The locked-rotor current of the motor can reach 4-7 times of the additional current, which greatly exceeds the promised value of the inverter, and the inverter will immediately carry out overcurrent maintenance.
(2) There is an impact load
Some production machinery is driven by electromagnetic clutches. After the motor starts, it is first run without load, and does not drive the load, as long as the electromagnetic clutch is engaged, the production machinery will start to run.
When the electromagnetic clutch is engaged, an inrush current will be generated, which may cause the inverter to trip due to overcurrent.
2. Code GF
The significance is that the output side of the inverter is short-circuited, and the possible reasons are:
(1) The output line is short-circuited
Broken phase-to-phase or ground-to-ground insulation of the cable from the drive to the motor, especially when the output cable of the drive is in a movable condition.
(2) Short circuit of the motor
If the motor is 'burned out' due to overload, the interphase insulation will carbonize, resulting in a short circuit between the phases.
3. Code SC
The meaning is that the upper and lower IGBTs of the same bridge arm are straight-through.
For example, if the ambient temperature is too high, the IGBT shutdown time will be extended, resulting in a 'pass-through' of the upper and lower tubes.
Overcurrent during acceleration and deceleration
1. Code OCA
The meaning is that there is an overcurrent during the acceleration process, which is caused by the acceleration moment preset too short.
2. Code OCD
The meaning is the overcurrent in the deceleration process, and it is the result of the preset too short deceleration time.
3. Code OPE
The meaning is that the PID function is preset inappropriately caused by the overcurrent.
4. Code OCB
The meaning is the overcurrent during DC braking.
5. Code OCS
The meaning is the overcurrent caused by the current sampling problem.
Overcurrent caused by a device malfunction
1. 'Overcurrent' with 0 current
(1) IGBT open circuit
If the IGBT is now open due to damage and there is no current, but the collector is always at a high potential, the drive module detects an "overcurrent" signal.
(2) The drive module has no output
If there is a problem with the driver module, there is no output signal, the IGBT will always be in the cut-off state, there is no current, the collector is in a high potential condition, and the CPU will also get an "overcurrent" signal.
2. Detection point disconnection
Sometimes, if the overcurrent detection line is either disconnected due to poor plug-in contact, or the transmission line itself is disconnected due to mechanical damage, the CPU may also get "overcurrent" regardless of whether current passes through the IGBT.
3. Cause of overvoltage (OV) tripping
The incoming line voltage of domestic inverters is 380V, and the upper limit of DC voltage is generally set at 700V or 720V; Due to the high upper limit of the incoming line voltage of the imported inverter, the upper limit of the DC voltage is always set at 800V.
The cause of the overvoltage on the power supply side
1. The power supply voltage is too high
For example, the capacity of the enterprise substation is low, and the load is heavy during the day, so the secondary voltage of the transformer is adjusted to a high gear. At night, the voltage is on the high side.
2. There is an impulse voltage on the power supply side
First, when thunder, the inverter is often tripped over voltage;
Second, in order to improve the power factor, the workshop substation needs to be equipped with power capacitors, and when the capacitors are closed, the inverter will also trip due to overvoltage.
Overvoltage in operation
1. Drag the system to release potential energy
If the braking resistance value is too large, the braking current and braking force are too small, and the weight is falling too fast, it may lead to overvoltage tripping.
2. Sudden loss of load
For example, during the operation of the production machinery, the belt suddenly breaks, and the dynamic torque suddenly increases, which will produce a great acceleration, so that the motor is in a regenerative state, resulting in overvoltage tripping.
Overvoltage during deceleration
1. The deceleration time is too short
When the frequency drops, the motor will be in power generation condition. If the deceleration time is preset too short, the synchronous speed of the motor decreases too fast, and the power generation is large, which simply leads to overvoltage tripping.
2. The reason for the braking circuit
The braking circuit consists of a braking resistor and a braking unit, which is used for discharging when the DC voltage is high.
(1) The braking resistance value is too large
Some equipment has a great inertia, and when it is in the condition of regenerative braking, the power generation is large, and if the braking resistance is large, the discharge current is small, and it will be overvoltage because it is too late to discharge.
Sometimes, the connecting wire of the braking resistor is in poor contact at the wiring, which can lead to the same consequence.
(2) The braking resistor is damaged
Since the braking resistor is a heating element, it is easy to damage. Once damaged, it will not be discharged, and it is very easy to trip due to overvoltage when decelerating.
(3) The brake unit is damaged
After the brake unit is damaged, it can not be discharged, and it simply trips due to overvoltage.
Overvoltage caused by sampling problems
If the voltage value obtained from the actual measurement is normal, and the data displayed on the display screen is large, it indicates that there is a problem with the voltage sampling circuit.
Fourth, the cause of the trip of the undervoltage (LV).
The cause of the undervoltage on the power supply side
1. Lack of power supply voltage
First of all, the capacity of the power transformer is not large enough, and the load is heavy, so it simply trips due to undervoltage.
According to the national standard, the lower limit of the incoming voltage is 380×0.9=342V, and the inverter is sampled in the DC circuit. Then the uniform DC voltage at 342V is 342×1.35=462V. However, the lower limit DC voltage in the inverter is usually set at 380V. This is due to the fact that when the voltage is under, the device does not damage the main circuit. Therefore, as long as the current of the motor is within the promised range and the drag system can operate normally, it can not trip.
2. The input terminal of the incoming wire is loose
When the terminal block of the power supply inlet line is loose, the contact resistance at the terminal increases, and the voltage drop also increases, and the voltage input to the inverter decreases, which may also cause undervoltage.
3. Phase loss on the power supply side
After the phase loss on the power supply side, the three-phase full-wave rectification at the inlet line of the inverter becomes a single-phase full-wave rectification, and the uniform voltage after rectification is only 0.9 times of the incoming line voltage, even if the power supply voltage is the upper limit, the uniform voltage after rectification is only:
ＵＤ＝0.9ＵＳ＝380×0.9＝378V
Therefore, it will also cause undervoltage tripping.
Undervoltage caused by a rectifier filter circuit
1. The rectifier tube is damaged
In a three-phase full-wave rectifier bridge, if one of the rectifier tubes is damaged, the uniform voltage after rectification will drop, causing the undervoltage to trip.
2. Faults in the current limiting circuit
A current-limiting circuit consists of a current-limiting resistor and a short-circuit contactor (or thyristor). If the current limiting resistor is damaged, the filter capacitor cannot be charged, resulting in undervoltage; In addition, if the short-circuit contactor is damaged, the current limiting resistor will also be damaged, which will eventually lead to undervoltage.
3. Aging of filter capacitors
As a result of the aging of filter capacitors, the capacitance decreases. If the capacitance is less than 85% of the nominal capacity, the DC voltage will be lower than normal.
4. The fuse is broken
Many inverters have fuses in their DC circuits, and if the fuses are now blown or in poor contact, they will inevitably cause undervoltage tripping.
5. The cause of overheating (OH) tripping
Causes of fever
1. The ambient temperature is too high
When the ambient temperature is too high, even if the output current of the inverter is not overloaded, the temperature of the inverter module may trip due to exceeding the promised value.
2. Overheating during operation
(1) The inverter is slightly overloaded
When the inverter is slightly overloaded, it will not cause overcurrent tripping, but if the heat dissipation is not very smooth, it may also lead to overheating tripping.
Some inverters separate the overheating of the rectifier module and the overheating of the inverter module.
(2) High carrier frequency
The carrier frequency is high, the IGBT has many switching times, the switching loss is large, and the temperature of the module simply increases, even if the current does not exceed the additional current, it may cause the overheating of the inverter module.
(3) Lack of IGBT driver
If the drive voltage of the IGBT is insufficient, the IGBT will simply overheat due to the expansion condition.
Heat dissipation reasons
1. Electric fan
The top reasons are:
(1) The filter is blocked
The fan of the inverter is equipped with a strainer to prevent foreign matter from entering. In dusty workshops, the filter screen on the inverter fan is often blocked by dust, and the demand is often cleaned.
(2) The fan is damaged
The fan equipped with the small-capacity inverter has a short service life and is simply damaged. When you hear a loud fan in operation, it should be replaced.
(3) Fan circuit fault
It is also common for the control circuit of the fan to have problems. Therefore, when it is found that the fan does not rotate, it is necessary to determine whether it is the problem of the fan itself or the problem of the control circuit.
2. Heat sink
Both the rectifier module and the inverter module are mounted on the heat sink, and there are many heat sinks on the back of the heat sink. The heat sink is also simply clogged by dust, causing the module to overheat.
3. The control cabinet is not well ventilated
Most of the inverters are installed in the control cabinet, and the control cabinet also has the problem of whether the ventilation is good.
Sixth, the control circuit tripping
Faults with the external input circuitry
1. Analog input circuit
(1) Code LOV
The significance is that there is a problem with the voltage signal input circuit. In most cases, the external voltage signal is input through the potentiometer, and in machines with frequent speed regulation, the sliding contacts of the potentiometer are simple and the contact is poor.
(2) Code LOI
The implication is that there is a problem with the current signal input circuit.
The current signal is often transmitted from the sensor, the distance is relatively long, and the line is relatively thin, which is simply caused by the disconnection of the wire, and sometimes it is the problem of the sensor itself.
2. Code EXT
The meaning is that there is a problem with the switching input circuit. If all the other input signals work, as long as one of them doesn't work, the problem must be in the input circuit that doesn't work; If all the input signals do not work, you need to check whether the 24V and 10V terminals on the inverter are normal.
Other common problems
1. Code DE
When the response vector control mode is selected, because the encoder is installed on the output shaft of the motor, and the output line is connected to the inverter, the center distance is often long, and the wire diameter is small, so the simple disconnection, or the connection line contact is poor, after the encoder has a problem, the operation of the motor is very unstable, and even rotates.
2. The display screen is damaged
This does not require code, and the horizontal and vertical display screen is not displayed. The characteristic is that the motor can operate, but the display screen is black and has to be replaced.
3. Code CCF
The meaning is that the keyboard is wrong. The relevant materials state that within 5 seconds of booting, if the CPU still does not get the information of the keyboard, it is considered that the keyboard circuit has a problem.
3. Poor contact with connectors
On the control board of the inverter, there are many connectors, which are sometimes loose and must be checked frequently.
|
More on that
|
Is there a restriction on the installation direction when Schneider installs the inverter?
It should be basically stored in the plate, the problem is that the plate with a fully enclosed structure is large in size, takes up a lot of space, and the cost is higher. This can be done by:
(1) The planning of the disc should be based on the heat dissipation required by the actual device;
(2) Profit ...
|
|
Schneider UPS Energy Saving Method
1. Flexible planning for on-demand expansion
Generally, the construction of data centers is not in one step, and the expansion of the next few years will be considered, and the UPS capacity is generally considered to be larger in the design.
|
|
Inverter control motor speed method - Schneider
1. Why can the rotation speed of the motor be changed freely?
Motor rotation speed unit: r/min number of rotations per minute, can also be expressed as rpm.
Example: 2-pole motor 50Hz 3000 [r/min]
4-pole motor 50Hz 1500 [r/min]
Conclusion:...
|
|
Features of Schneider explosion-proof inverter box
1. Aluminum alloy shell or steel plate welding, surface spraying;
2. Built-in inverters, circuit breakers, signal lights and other components produced by domestic or Schneider and other companies;
3. It is mainly adjusted by changing its output frequency to adjust the speed of ordinary three-phase asynchronous motor, so as to reach the production process.
|
|
Advantages and disadvantages of closed busbars compared with open busbars - Schneider
The advantages of closed busbars over open busbars are:
1) Closing the bus duct can reduce the grounding fault, avoid the short circuit between phases, basically eliminate the grounding defect caused by external moisture, dust and foreign objects, and improve the continuity of generator operation.
2) Eliminate ...
|
|
Features of Schneider explosion-proof inverter boxes
1. Aluminum alloy shell or steel plate welding, plastic spraying on the surface;
2. Built-in inverters, circuit breakers, signal lights and other components produced by domestic or Schneider and other companies;
3. It mainly regulates the general three-phase difference by changing its output frequency.
|
|
Suppression of higher harmonics of inverter - Schneider
1. About the management of higher harmonics on the output side of the inverter
The magnetic noise skills brought about by the communication harmonic components contained in the output waveform controlled by PWM control have been increasingly used in various inverters, such as the selection of higher frequency switching components, the installation of filter devices at the output end of the inverter, etc.
|
|
Schneider low-voltage circuit breaker selection
1. Determine the type and maintenance situation of Schneider circuit breaker according to the maintenance requirements of the line, and determine the selection of frame type, device type or current limiting type. Generally speaking, the Schneider frame circuit breaker can break the short-circuit current with a large device type and a large volume. Usually, the branch line chooses ...
|
|
THE DIFFERENCE BETWEEN SCHNEIDER CIRCUIT BREAKER EASYPACT AND MASTERPACT
First of all, both are low-voltage circuit breakers (below 1000V)
Let's start with Schneider Masterpact, which is a structural circuit breaker. The current rating of the structure varies from 800A ---- 6300A. The Masterpact series is divided into M series and MT series. The M series has been on the market since 1986 and was screened and delisted in 2002.
|
|
Schneider AC contactor precautions
There are many series of contactors: LC1-SK series: below 6ALC1-K series: 6A-16ALC1-D series: 9A-150ALC1-F series: 115A-800ALC1-B series: 750A-1800A
When installing, it should be in accordance with the regulations...
|
|
Schneider circuit breaker technical issues
1. Overload maintenance failure: The circuit breaker should be tripped for maintenance when the current exceeds the rated current, but sometimes the overload maintenance failure may be due to some reasons. This may be due to incorrect overload maintenance settings, long overload periods, thermal aging due to successive overloads, etc.
2 ...
|
|
Rebecca · Lowell · Edwards Schneider Electric's first Global Head of Communications
GENEVA – Rebecca Lowell Edwards, who has been with the International Olympic Committee for the past 18 months·· has joined Schneider Electric as the company's first global communications chief.
In the new work that starts today, love ...
|
|
Circuit breaker mechanical characteristics tester operation steps - Schneider circuit breaker
Circuit breaker action time test.
The closing and opening control lines of the circuit breaker mechanical characteristics tester are respectively connected to the secondary control line of the circuit breaker, and the lead wires of each break of the circuit breaker are connected to the mechanical characteristics of the circuit breaker with the test wiring.
|
|
Schneider inverter inverter field interference solution
1. Use software anti-disturbance method
In detail, the carrier frequency of the inverter is lowered through the human-machine interface of the inverter to an appropriate scale. If this method does not work, then the following hardware anti-disturbance method can only be adopted.
2. Carry out positive ...
|
|
Schneider appeared at the 5th China Power Distribution Technology Summit Forum
Beijing, China, September 14, 2020 – Today, the 5th China Power Distribution Technology Summit Forum 2021, held by China Electric Power Research Institute Co., Ltd. and the Science and Technology Development Service Center of China Electric Power Council, opened in Beijing. The theme of this forum is "Supporting the Strategic Policy of Carbon Peaking and Carbon Neutrality, Building a ...
|
|
Causes of Schneider UPS power supply damage
1. Air conditioning: It is generally forbidden to use UPS power supply, because the air conditioning is very large and belongs to the rational load.
Not suitable for belt loads
2. Motor: It is necessary to choose a large-capacity UPS power supply, because it is a rational load, and it is ...
|
|
Schneider miniature circuit breaker C type D type difference
The difference between Schneider OSMC32N3D10 and OSMC32N3C10
After type comparison, one is Schneider D10A and the other is Schneider C10A.
Schneider circuit breaker type D, suitable for power equipment, such as motor load, air conditioner, etc.;
Schneider circuit breaker type C, suitable ...
|
|
How to operate the transformer DC resistance tester – Schneider
1. The instrument test has a total of YN winding three-phase test, YN winding three-phase phase-by-phase test, low-voltage winding magnetization method test of iron-core five-column low-voltage angular transformer, low-voltage winding phase selection test and general four-terminal method of ironcore three-column low-voltage angular transformer.
...
|
|
Schneider low-voltage circuit breaker selection method
1. Determine the type and maintenance situation of Schneider circuit breaker according to the maintenance requirements of the line, and determine the selection of frame type, device type or current limiting type. Generally speaking, the short-circuit current breaking ability of Schneider frame circuit breaker is larger and larger than that of device type. Usually, the branch line chooses ...
|
|
Schneider ATV630 VFD series advantages
Depending on the customer's requirements, wall-mounted drives, built-in cabinets and floor-mounted free-standing solutions in protection classes IP 21, IP 23, IP 54 and IP 55 are available.
Thanks to the built-in pump monitoring function, the device reacts immediately when pump efficiency drops, resulting in ...
|
|
Contact
working hours
