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7

In the past whenever I needed a rotary encoder, I took apart a computer mouse. I do not know if they will meet your requirements, but there's nothing cheaper.


6

In the wire & cable business, the device you describe is called a dancer, for the way its components move about while regulating the tension in a rope or wire being unspooled from a large coil. The simplest examples use a rim brake which drags against the flange on the big spool. The rim brake is on a lever arm and the end of the arm is attached to a ...


5

Connect them with gears and they will run at the same speed - any sensor / control will have an accuracy range


5

If I am not mistaken, you can use an H-Bridge for that. If you are using an arduino for example, there are a few motor drivers like L298N which do exactly that job (control the direction and speed of a dc motor).


4

What you'll find is that most electric motor (not all) exhibit a curve like the following So at very low rpms they tend to have a very stable torque and low power. As rpm increase at some point Power tends to flat out and torque start to drop, because just like @jko said : $$Power = M_t \cdot \omega=M_t \cdot 2\cdot\pi \frac{n}{60}$$ So there is always a ...


4

I suspect this is just a Brushless DC Electric motor What Dyson seems best at is marketing their tech and branding it to sound exciting.


4

Single stage and centrifugal are describing two different properties. A single stage pump is a pump that only has one acting impeller stage doing work on the fluid. If you put two pumps in series, you could say that you have a two-stage pumping setup. Some pumps are built with multiple stages - this is usually for high pressure applications. A centrifugal ...


3

Different electric assist bikes will present different circumstances. For instance, a standard hub motor (front or rear wheel) will have permanent magnets which react with the iron in the stator. You can feel what is called cogging when rotating the wheel by hand, without power. This is energy expended by hand, but also applies when pedaling without applying ...


3

A pneumatic cylinder is linear by definition The form factor for a cylinder defines this. You can turn this linear motion to rotary via a crankshaft or rack & pinion, to give two examples. You can also purchase a rotary pneumatic actuator, and, yes, there are some knuckleheads out there calling them "rotary cylinders." These people should be ...


2

I'd personally go with Magnetic actuators, as those are highly reliable and can flip between their states extremely fast. As they are providing linear motion in a rather short range, you would need some lever on the hinge, but the part itself can be the hinge. Most magnetic actuators also have a rather small build volume, so the actuator might even be ...


2

This is not an answer, it is just pointing out an error in calculations. DC motor torque discrepancy A DC motor at 2750[rpm] and 250[W], outputs $$M=\frac{P}{\omega} = \frac{P}{\frac{2\cdot\pi\cdot n}{60}} = 60\frac{P}{2\cdot\pi\cdot n} =0.8681 Nm$$ So your torque after the sprockets (if you are increasing the speed) is even less, probablyt around .5Nm. ...


2

A commonly used motor for lathes is the DC shunt motor. The big advantage is that the speed remains constant irrespective of the load. The working principle of a DC Shunt Motor is that whenever it is turned ON, then DC current flows throughout stator as well as the rotor. This current flow will generate two fields (namely pole as well as the armature). The ...


2

Like you said there are many ways to do it. Computer controlled and usually expensive. Dynamometers. These are the tools built exactly for this type of task. Obviously they are amognst the most expensive for the job. The most difficult part would be to determine the specs (what is the maximum torque, what is the control resolution, is it computer controlled ...


2

When you bump the plate on a thread off the edge, the plate tilts, inertia of the motor drives the plate to a larger angle. Deformed plastic grips much stronger than what motor can move. To avoid this you need to reduce this bending of the plate due to inertia. You could make a plate thicker. It will bend less. It will capture the motor's shaft less when it ...


2

Considering that this is a class project, depending on what you use to control the DC motor, you might be able to use current limiting. The technique is called current sensing. When a DC motor is running freely then it draws much less current than when its about to stall (see image below) When the current stars to increase that is a signal that the DC motor ...


2

You want something called a gearmotor, which is a modestly-sized DC motor that can run in either direction at a variety of speeds, depending on the voltage you feed it. You select the appropriate gear ratio to yield the RPM you want. See the Marlin P. Jones & Associates on-line catalog for a good selection of inexpensive gearmotors. Also note that it is ...


2

The speed is not a factor but the acceleration of the person is. The equations are m= mass of the person $ \mu=friction\ index$ $\alpha= acceleration$ g=9.8ms^2 $\theta= angle\ of\ the\ ramp$ $$F_{net}=mgsin \theta-\mu mcos\theta=ma $$ Dividing both sides by m we get $$a= g sin\theta-\mu cos\theta$$ This is the acceleration downslope if the person is ...


2

let me take a stab at this. Similar to linear motion of a mass m on a frictionless surface or in space, that a force $F$ no matter how small will move a mass no matter how big, albeit with smaller acceleration if the mass is bigger or F smaller. $$F=m\alpha$$ A torque no matter how small will turn a disk or a randomly shaped piece of rock or an ice skater ...


2

One option that has no parts that wear out is eddy current brake. It consists of a metal disc, and a magnet in close proximity to it. The magnetic field will cause eddy currents in the metal disc, which in turn cause a torque that opposes the rotation. The energy is converted into heat in the wheel, which can be cooled down by either air flow or with liquid ...


2

For Permanent Magnet DC motor, even if you rotate it with the constant rate the back EMF you'll get externally from the motor connector pins ought to be more similar to a rectified AC. However, I wouldn't expect it to be exactly sinosoidal.


2

The simplest idea for me would be to add on the bottom (and the top cover) small inserts of the following shape (dimensions will vary depending on the size of the ball, etc) They would guide the ball towards the opening with the right velocity. You only need to provide adequate clearance for the rotating part, which from your side view should not be a ...


2

Figure 1. A Kinetrol rotary actuator. This type of rotary actuator is also known as a vane type. This one has a 90° action and is popular for controlling ball or butterfly valves. Figure 2. A rack and pinion style rotary actuator. Image source: Hydraulics Pneumatics. These convert linear motion into rotary. The angular rotation is limited only by the length ...


2

Actually if you want to keep accuracy and increase the torque you can use a gearbox that reduces the input Rpm. So you will be Sacrificing the speed for the increased torque and precision. Its also linear so if you need to go from 200gr to a kg you need a great ratio of. 5. If you had to go higher than 10 then the forces would be significant and you'd need ...


2

An alternative to an H-Bridge (preferred method if you are already using a controller - it also lets you use those overkill relays for other projects) would be having +/-6V at the motor. This would mean a 12V supply with one leg of the motor at a regulated 6V. You connect the second leg to 12V for one direction and 0V for the other direction, getting you 6 ...


2

You can do this with a pair of Omron programmable timer modules that mount onto DIN rails, no software required. They are extremely flexible and can be easily configured to perform a variety of tasks like this. They are basically a set of relay contacts which are exercised by an internal clock, packaged into a small plastic enclosure with a clock display and ...


2

Power rating of a motor is the mechanical power out. Divide that by efficiency and you should roughly get electrical power in. Efficiency will be different if not at full-load. To get 6W mechanical @ 60% efficiency, you have to put 10W electrical in. You have a problem. Driving motor correctly means generator is going in the incorrect direction, which ...


2

Those are called flux rings. They're standard on pretty much all motors. They close the magnetic loops in the core so the flux doesn't need to escape into the air to find its way back to the other end of the coil. https://www.made-in-china.com/showroom/funtainmotorjason/product-detailXBwJeYrcLqkM/China-Dc-Motor-Rs-590-with-Flux-Ring-for-Steering-Lock-...


1

Assume the cable is simply looped around the pulley in counter-clock-wise direction, the initial position should be as shown on the sketch (by the side of pulley). Further assume the pulley and the motor are fixed in space, and the platform is attached to another end of the cable. Then the tension in the cable equals mass of the platform times gravitational ...


1

Try researching USB to UART solutions as an alternate. RS232 ports on desktop computers are thing of the past, thus you are limiting your design. USB port are pretty common with computers thus a USB -> UART might be simpler modern solution with added features. Note this is still a 1 - 1 communication, but with additional USB port on the desktop, the ...


1

RS232 is way more simple - it's strictly 1 to 1 communication, no addresses, no negotiation, no error correction (just very rudimentary optional verification - parity bit, usually unused). There are optional (also usually unused) control lines or special byte values to pause/unpause transmission, not even any indication there's anything connected (no ...


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