The power of a1 hot bed is very high when it is heated, and there is a power limit in the use of my power supply, which leads to the tripping phenomenon when using the printer. From the trend of his power change, the power of the printer will be very high only when the hot bed rises from room temperature to set temperature, which is 1000w. I tried to modify the gcode to reduce the heating rate in the early stage and reduce the heating power. When I finished slicing, the time from clicking ’ Start Printing ’ to the start of the printer was the time when the printer downloaded the print file. The printer is still heating up at 1000w power, and it will only print according to my gcode after file downloaded. This means that the heating of the hot bed is uncontrollable during the time the printer downloads the file, whether there is a potential security risk.please fix it or tell me what should Ido to aviod this situation.My solution is sand the file and start printing when the file is in the SD card.
I don’t know this for a fact but the heater control is more likely a simple on/off instead of multi level or analog.
If the software turns on the heater and doesn’t stay monitoring the temperature where it overshoots badly during a download, that sure sounds like a big safety issue.
But if what it’s doing is tripping a breaker and would regulate properly if it had adequate power, that isn’t a g code or printer issue and is just thermally tripping your breaker from a high load for too long.
If that’s what is happening, you can possibly manually warm up the bed before starting the print by raising its temperature in stages where the heating isn’t quite as long and is less likely to trip the breaker.
But it sounds like it all comes down to an inadequate power breaker and supply that will be running close to its limits anyway. Over time breakers weaken anyway and might start tripping during printing and not just warm-up.
But the power shouldn’t really change during warmup. It should be the same until the printer starts regulating. What it sounds like is the breaker is thermally tripping after a high load for a little too long which means you are close to the edge anyway.
Thank you for your reply
Regarding whether it is a simple on / off, I attach my gcode changes here
Original heating gcode :
;===== start to heat heatbead&hotend==========
M1002 gcode_claim_action : 2
M1002 set_filament_type:{filament_type[initial_no_support_extruder]}
M104 S140
M140 S[bed_temperature_initial_layer_single]
My gcode
;===== start to heat heatbead&hotend==========
M1002 gcode_claim_action : 2
M1002 set_filament_type:{filament_type[initial_no_support_extruder]}
M104 S140
M140 S28
M400 S10
M140 S31
M400 S10
M140 S34
M400 S10
M140 S37
M400 S10
M140 S40
M400 S10
M140 S43
M400 S10
M140 S46
M400 S10
M140 S49
M400 S10
M140 S52
M400 S10
M140 S55
M400 S10
M140 S58
M400 S10
M140 S61
M400 S10
M140 S[bed_temperature_initial_layer_single]
This is to divide the entire heating phase into ten seconds of pause every three degrees of heating.
Facts have proved that heating with this scheme will control the heating power of A1 at about 350w ( I measured it with a power meter ), and this power will increase with the difference between the current target temperature and the actual temperature.
Therefore, I think the heating power should be variable rather than always 1000w.
Regarding my power limit, the circuit I used limits the power to 800w, which cannot be changed because I am rented. Therefore, it is reasonable for the circuit breaker to cut off the circuit. The actual irrationality is that I used an overpowering electrical appliance ( A1 ), which is also the reason why I want to reduce the heating power of the printer.
I tried using a hot water bag to preheat the hot bed, and it worked well, but it was troublesome. After that, I tried to manually heat up the machine, such as 25 ° C at room temperature. I set the target temperature to 30 ° C, and then set it to 35 ° C when the temperature was raised to 30 ° C, and so on. Heating to the target temperature of printing, such an operation will not cause the power to trip. Finally, with the help of customer service, I integrated this operation into gcode, which is that some of the above gcode slice files can perfectly solve my problem if they are selected and printed from the SD card, However, when clicking from the computer to start printing instead of sending first and then printing, the hotbed will heat up quickly at 1000w when downloading files, which is the reason for tripping.
After the temperature of the hot bed is stabilized, the power will remain at about 120 w, and no problem will occur at this stage.
So I think my idea that his rapid heating up during the download file phase is uncontrollable is reasonable.
If you have a solution please tell me, thank you
My circuit is 220v voltage, power limit of 1000w, if the circuit is 110v the power will not exceed 350w, this is the official website information
I believe the difference in heating comes from the voltages. Someone said in another thread that the printer uses line voltage for the bed heater.
Meters and measurements get tricky because you have to know how they make the measurement to know what the instruments are actually saying. Depending on how Bambu is regulating the heater, you may be seeing average power because of a duty cycle that is turning the heater on and off faster than your meter is able to see. Not so important to this but something to be aware of.
I can think of a few possible solutions. Double check the power input rating for your printer but I bet it can handle 90V to 260V or so. If true, you could use a sufficiently-rated transformer to reduce the voltage to your printer. Since the bed heater is running off line voltage, it will see a lower voltage and use less power. That could get you into a range where the breaker can be happy. 2:1 transformers are plentiful and you could go from 240 to 120V and significantly reduce the heater demand but don’t do this unless you buy a prebuilt unit or know exactly what you are doing since line voltage can be deadly.
The other way is to use a sufficiently big UPS/emergency power supply to where you charge it at a rate the breaker is happy with and then whatever your printer needs it gets from the UPS. Just be aware that you have to unplug from mains or stop the UPS from charging because most pull the load plus charging current when they are charging which would make your problem worse.
The transformer method would probably be cheapest. But other than those, not much more you can do I think.
I have considered using a transformer to limit the power of the printer. This scheme has also been practiced and proved feasible by others, but my doubts still exist. The heating of the hotbed during the download period is not limited. I can currently print normally by sending a modified gcode slice file, but it is obviously better to use a 220v voltage and start printing directly on the computer.
I made a video to explain the problem and my solution,where you can see the change of power change before and after adjustment
(拓竹A1热床峰值功率太高？修改gcode解决，适用于宿舍学生党和农场主等受功率限制的群体_哔哩哔哩_bilibili)
Can you help me analyze the reason for the power difference between clicking to start printing and selecting printing from the SD card after clicking send?
Sorry but I don’t even have an A1. If you go with a step down transformer I’d buy a solid one from a good manufacturer and be careful about the rating. Good luck.