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Ah, yes, that could pose a problem as I need a pretty constant RPM while doing the vibration measurements, otherwise the vibrations would be hard to identify on the FFT graph if they keep changing frequency due to RPM changes.
I don't have much need for a good response time, but the smooth...
You mean the universal motor will burn out with such a high load? Of course, the load would be a propeller, and the PWM to the motor would be adjusted for 3000 RPM, meaning maybe the PWM duty cycle is only 30% for a small propeller and maybe 70% for a bigger propeller. But the biggest propeller...
My mind keeps on working and I stumbled upon something new to me, universal motors.
These motors are everywhere, also in 2kW power tools like 230mm angle grinders. I took a look at my 230mm angle grinder, rated 2000W and 6000 RPM. The gear ratio is 3.67:1 so when the grinding wheel spins at...
I have been talking to a friend, and he thinks the motor flywheel will help even out any voltage variation from the input voltage, to a point where it might not be a concern.
I will start out by adding 1000µF, this should keep the rectified DC voltage above 200V even at full load. I do know...
Thanks, I'll do that.
Would this mean that those 2A are the efficiency losses? That equals roughly 25% of the max current of 8.3A - just what schmitt trigger anticipated regarding motor efficiency.
I have been doing some more calculations.
According to the balancer build thread, people are using 3000 RPM when balancing their drone props. I don't know if this RPM is applicable for larger props as well. But lets say it does. My currently largest prop is a 2-blade 27x10" which is 27" in...
The dynamic balancer thread is here:
https://www.rcgroups.com/forums/showthread.php?2337523-Dynamic-Propeller-Balancer-Build
It uses an accelerometer to measure the imbalance, a Teensy board (kind of a powerful Arduino) for data collection and motor controller interface and it has a...
If the input voltage/current "pulse" is clipped by the SCR, the capacitor would have to supply the current for even longer, though the load would probably be lower in this case as the total output voltage would be lower. Something to think about, thanks.
schmitt trigger, yes, I will probably need pure DC or some higher frequency PWM version of it. Thanks for the explanation of cogging, this is also something I'll need to keep in mind, luckily the treadmill motor comes with a flywheel already attached.
ronsimpson, the balancing software does...
dr pepper, thanks for the link, I'll have to look through that.
schmitt trigger, you are right, but it will feed the motor in 100Hz pulses, which is what I'm trying to avoid using PWM of a much higher frequency. I'm afraid the 100Hz pulses will create vibrations that could saturate the...
I did some more searching and I think I found a way to calculate the capacitance for question 1:
http://www.skillbank.co.uk/psu/smoothing.htm
I assume my input voltage can reach 240V AC worst case.
This will give a worst case rectified peak-peak voltage of around 240V * 1.414 = 340V. So a 400V...
Hello forum,
I need a "big" electric motor for a dynamic propeller balancer project where I need to control the motor speed (not accurately to a specific RPM, just up/down), and a treadmill motor seems to be just the thing for my project.
I found a treadmill motor as replacement part at a local...
Hi JDW1,
I had a look trough the thread and also my layouts, and I can see I used a SMB package diode on the PCB but no mention of a specific device on the schematic, but there is a very good chance that I used a S320 3A 200V schottky rectifier as I have a lot of them in stock. The 1N5817 was...
If I were to put the spark inside a steel container, like a 3" long 2" ID steel tube with 1" openings in each end, would it be possible for any of the noise to escape that container through those end openings if they are smaller than a wavelength?
I guess I could try to use resistive wire for the HV wires. Would it give the same just to add a resistor in the HV circuit? How much resistance are we talking about, a few ohms or something in the kΩ range? I don't think I can get more than 20Ω per meter with resistive wire, otherwise it gets...
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