Recent content by bbq_build

Thanks Tom. Sometimes manufactures use lbs as the unit of the static load. For most google unit conversions , they use pounds. Are they the same thing? In other words, is 1 lbs = 1 pound? lbs does not sound like an abbreviation of pound.

I know how to do conversion using google. The confusion I have is whether the manufacturers and the electric scale take gravity into consideration when showing the numbers. For example: When I measured the weight of the object using a scale, it reads 5kg. So, in Newton, it is 5kg*9.81m/s2 ~=...

Hello, I measured an object using an electric scale. It is 5kg. I want to select a linear actuator such that when placed vertically, it can keep the object on hold at a fixed height. In this case, what static load (in lbs and Netwon) should the actuator be capable of handling? I am confused by...

Thanks. What is l, GJ and L? How do I find those values?

"to fall through some distance"? I think the book mentioned about spinning. What should I do in regard to the "Collet"? I don't have it but the equation requires the MOI of the collet.

Thanks. I don't have a motoring dyno. I am trying to measure the inertia at home without fancy equipment. The only method I know of is described in Fig. 2.10.5 on 2-73. https://www.elsevier.com/books/dc-motors-speed-controls-servo-systems/zhou/978-0-08-021714-7 Anybody knows what Collet is...

Hello, I need to measure the moment of inertia of a DC motor's rotor. Any suggestion? Thanks

Thanks David for the graphs. I connected a small motor hub to the gearhead of the motor. Then, I measured the voltage, current and speed of turning (in RPM) using a tachometer. I found that the measured voltage is a bit less than the supplied voltage. This is probably due to the Back EMF. I am...

Thanks. My tachometer has arrived. Could you please let me know the proper way to measure Ke by back driving the motor and using a tachometer and voltmeter?

I have ordered a tachometer. It will arrive in about two days. Also, ordered a LCR meter to measure the inductance. From what we have gone through, it looks like the results are also affected by the order of measurements. Shouldn't the results be the same regardless of method and order of...

I did two sets of experiments. In the first set, input voltage was 4V and 10 runs. The averaged measured voltage was 0.533V while the averaged measured current was 5.834A. R = V/I = 0.09 Ohms. Using the recommended equation, the Back EMF is 0.02794V. In the second set, input voltage was 5V...

Thanks. So, in my model, will it be reasonably good if I set Kt=Ke=0.76 and Resistance to be 0.1 Ohms?

I see. So, what is the purpose of measuring the resistance by stalling the motor shaft while measuring the voltage across the motor and the current in series with the motor? I am a bit confused now. In my previous post, I mentioned that based on the torque vs current curve from the company, 0...

Thanks David. In this equation, I would need to have the back EMF first. I think now we are trying to calculate the back EMF using the resistance. So, there are many underlying factors that affect the results. Based on the experiments, should I choose 0.0868, 0.09, 0.1 or 0.123 Ohms as the...

Thanks David. I did one more set of tests. 10 runs at 5 volt from the power supply. The averaged measured voltage was 0.638V while the averaged measured current was 7.35A. The calculated resistance became 0.638/7.35 = 0.0868 Ohms. When I tried input voltage at 6 Volt from the power supply, I...