Problems of film blowing machine circuit

The film blowing machine is prone to encounter a lot of problems during the operation. Today we will make a simple summary and answer to the common circuit problems.

Question 1: When the heating ring of the die head of thefilm blowing machinestarts to heat up, the pointer of the ammeter suddenly reaches the maximum value, but the result is not heated, what's the matter?
Answer:
1. The heating sensor on the die head heating ring does not sense the heating temperature, causing the ammeter to display abnormally. Just fix the heating sensor, don't loosen it, and make it sense the heating temperature.
2. The wire of the heating coil is wrongly connected, and it should be re-wired
3. The thermocouple wire is broken, or the contact is poor, reconnect or replace with a new thermocouple
4. The thermocouple and temperature controller model do not match, it should be E type wire with E type thermostat.

Question 2. Why does the frequency converter of the film blowing machine often trip?
Answer: The main problem is that the motor is overloaded. The inverter trips due to its own protection.
First check whether the heating ring of each zone of the screw is normal, or increase the temperature a little. Secondly, the inverter can be cooled by a fan. Finally, check whether the motor is overheated and whether the inner bearing is broken, so that the motor is stuck and short-circuited directly. You can find the solution to the problem by referring to the instruction manual of the inverter according to the display symbols on the motor control keyboard. The main reason is that the motor generates heat with low frequency and poor heat dissipation, and the heat dissipation of the ordinary motor itself is insufficient when the fan blades are low. If the heating temperature is not enough, the overload caused the inverter to trip or burn the motor. This can happen if the inverter parameters are adjusted improperly.
The solution is as follows: You can reset the frequency conversion parameters, or repair the motor to a good condition!

What needs attention in this process is the selection of motor and inverter
1.the choice of film blowing machine motor
First of all, the power of the motor should be selected according to the average power and maximum power required when the load is moving, converted to the motor shaft side (there may be reducers, pulleys, etc.), and the overload capacity of the motor should also be considered. Motor manufacturers can provide the torque characteristic curve of the motor, and the characteristics of the motor will change at different temperatures. By the way: the order of selection is of course to select the motor first and then the inverter according to the motor, because the ultimate goal of control is not the inverter nor the motor, but the mechanical load.
2. Selection of Inverter for Film Blowing Machine
The first thing that should be emphasized is that the selection should be based on current. For general loads, the inverter can be selected according to the rated current of the motor, that is, the rated current of the inverter (that is, the maximum continuous working current in a normal environment) is greater than the rated current of the motor. However, the emergence of extreme conditions must be considered. Therefore, the inverter also needs to be able to provide short-term overload current. (Note: The current of the motor is determined by the mechanical load) .

Question 3. The heating ammeter of the film blowing machine has been heating, but it can't be added. What should I do?
Example: When starting to start heating, the temperature needs to be adjusted to 200 degrees, but it will not go up when it reaches 100 degrees, but it shows that the heating is continuing, that is, the temperature does not go up.
Answer: The heating ring is aging and heating slowly. The principle of the heating ring is similar to that of the battery. The inside is a conductive device. We usually connect the live wire and the neutral wire, and the heating ring is automatically energized and heated. If it ages or has poor contact, Or poor contact of the temperature sensor may affect heating. It is best to check the circuit or replace with a new heating coil. Check the heating coil. Use the resistance file of a multimeter to test whether there is resistance at both ends of the wiring. If it is broken, there will be no resistance.

Question 4. What is the reason why the two incoming wires of the heating coil of the film blowing machine are displayed as live wires?
Answer: It means that there is no neutral wire in the heating coil. Check whether the neutral wire is disconnected or broken, and you should reconnect it.

Question 5. The winding speed controller of the film blowing machine seems to have electricity, but what's the matter with the motor not rotating?
Answer: This phenomenon is a lack of phase. Check the circuit to see if a live wire is dropped or the contact is not tight.

Question 6. Why does the temperature number of the temperature control meter of the film blowing machine keep rising?
Answer: We believe that this phenomenon is caused by the damage of the solid state relay, which causes the temperature to rise continuously, and the temperature is constantly heating. The method to check the quality of the solid state relay is to test the electricity with an electric pen. Generally, one wire is powered and the other wire is not. Electricity, if both wires have electricity, it means it's broken.

Question 7. The inverter will jump off when the host is turned on, what's the matter?
Answer:

1. The host circuit meets another circuit, check whether the circuit along the line is damaged or pressed, resulting in poor contact
2. The host is under-voltage, lack of phase, check the circuit with a universal meter.
3. The main engine motor bearing is damaged, causing line overload and frequency hopping.

⁠Question 8.Why is there no current in the ammeter?

Answer:
1. The solid state relay is damaged, "If the two wires are tested with an electric pen, it means it has been damaged."
2. The hot or neutral wire of the heating ring is open, causing power failure,
3. The circuit of the ammeter is open, check the circuit