Questions tagged [motors]

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votes
1answer
4k views

Type of motor for a small lathe

I am working on a design for a small lathe that could double as a horizontal drilling machine like a Westhoff. My plan is to have specific geared speeds, rather than continuously variable speed. I ...
0
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0answers
45 views

How to calculate the right motor size & type for a soil sifter?

How would one calculate the proper size of an electric motor to properly drive a soil sifter? Assumptions: Screen: flat, 18"x24", 1/4" to 3/4" wire cloth (interchangeable screens), total weight (...
10
votes
1answer
882 views

How to calculate Power of motor when used as a generator?

How can you calculate how much power can be generated by a motor when used as a generator (like a motor used in a wind turbine)? Does the power depend on how fast the magnet is rotated? If so, is ...
3
votes
1answer
105 views

Regenerative Braking of DC motor

I'm looking to implement a simple regenerative braking circuit in order to measure how much energy could be regenerated using a DC motor. My knowledge of electronics is very basic to say the least so ...
0
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1answer
2k views

How to calculate temperature rise on AC induction motor in an evaporative cooler centrifugal blower?

A neighbor recently asked me if his evaporative air conditioner was running correctly because he felt the blower drive motor and it was too hot to leave his hand on it for long. I was surprised to ...
1
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2answers
802 views

How to size a motor for a lifting mechanism?

I am building a machine that has to lift a load of approx 80 kg including the material and lifting mechanism's weight. The velocity requirement is quite low (around 4.5 cm/s or 0.045 m/s). The whole ...
7
votes
2answers
152 views

Under what circumstances would one need or not need an electronic brake for a permanent magnet motor?

My company was asked to design a custom product several years ago. The original requester never bought it, but we've sold several a year through distribution. It's been a small side-line for a while, ...
2
votes
2answers
395 views

How can I use 2 motors to increase rpm on one wheel? [closed]

I want to add power of both motors in such a way that it increases the RPM on a wheel, to be used in a tricycle.
2
votes
2answers
87 views

Setting up a “pulsing” motor?

I need to set up a system with a DC motor that will cause it to run for a small period of time, then stop, and then be able to repeat this until disconnected from its power source. Any ideas of how I ...
1
vote
1answer
63 views

Technical obstacles in making a noiseless thermic motor? [closed]

There seems to be no noiseless thermic motor for cars or motorcycles on the market. Is there a technical obstacle at making such a product ? Is there a way to isolate/eliminate noises from the ...
1
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0answers
32 views

two parameter equation to approximate torque v.s rotor speed curve of AC induction motors

Like the title states, I am looking for a way to approximate the torque vs rotor speed curve of an AC induction motor using the standard specs given in a specs sheet: LRA Pull-up torque break down ...
0
votes
1answer
111 views

Fast and quitet linear actuator for lifting less than a kilo

I'm looking for a linear actuator that can lift a microphone of about 700 grams. It's for a goose-neck microphone (together with shock-mount) that will pop out of a small pulpit. Only the top part is ...
3
votes
1answer
220 views

A couple of questions about making an electric hobby car from scratch [closed]

So I'm a high school student doing some competition (a wallet-sized one, unfortunately) and I'm supposed to make an electric car. Think an RC-car, (about that size) without the remote control. I want ...
2
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4answers
66 views

What are the key properties to consider when choosing a DC electrical motor for linear movement?

I would like some help defining the specification of my motor, as I have little experience in this field. I've tried researching through Google, but the information is insufficient or unrelated. The ...
3
votes
0answers
134 views

A round, plastic pinion in a lock?

I'm looking at a teardown of a Masterlock. The guts look like this What's strange to me is the black, plastic pinion that appears to be smooth and a strangely shaped cam: Here's the cam magnified: ...
4
votes
1answer
169 views

Are typical worms and worm gears self-locking?

Does anyone know if typical/common worms and worm gears self-locking (plastic or metal)? Are the self-locking ones specially designed (with specific angles) in order to be self-locking? By self-...
3
votes
1answer
5k views

Calculating torque needed to climb a graded hill

I've been designing an electric skateboard which is driven by only one of the rear wheels (for the moment). As I was picking out motors for the board, I soon realized I would need to find a balance ...
2
votes
2answers
2k views

Rotating two shafts together - coupling rod?

Are there any established (compact and simple) solutions for turning two 5mm rods/shafts side-by-side together by driving a singe motor? The torque is about 5kg-cm. The one I'm thinking of is the ...
1
vote
1answer
52 views

Will AC Motor Maintain Speed of Descending Object

Suppose we have an AC motor which needs to lower an object at a set speed. We use a PID loop to determine and correct positional errors. Presumably the PID loop will keep the current low as most of ...
1
vote
2answers
443 views

Actuator recommendation for oscillating motion of a 6 kg object

I have a general question without many specific parameters, but I hope someone will be able to point me in the right direction - at least what actuator best serves my purpose. I am working on a ...
5
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0answers
93 views

How do DC motor parameters scale with motor size?

Consider the following DC motor parameters: Rotor resistance, $R\ [\Omega]$ Motor constant, $k_t\ [\mathrm{V/rpm}]$ Inertia, $I\ [\mathrm{kg\cdot m^2]}$ How do they scale with motor size? Do $R$ and ...
3
votes
1answer
2k views

What determines the maximum torque of a DC motor?

What determines the maximum torque of a DC motor? How is this related to the equations $$E=k\omega$$ $$T=kI$$ where $E$ is electromagnetic force / voltage (V) $\omega$ is rotational speed (rad/s) $...
4
votes
1answer
99 views

High RPM - Stepper vs Brushless Motor

I need to spin a threaded rod to raise a picture on a frame. The weight of the picture + the parts that it hangs on will be around 6 pounds. Two motors are going to be used to lift it via threaded ...
1
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0answers
107 views

Motor for inverted rotary pendulum

I'm building a rotary inverted pendulum to demonstrate reinforcement learning principles, however I have little experience with mechatronics. I will be building something similar to this. However ...
2
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0answers
80 views

How do I calculate the best mass for the highest linear speed?

I have a motor whose specifications say that its torque is 190g*cm. If I have the formula for the mass of the wheel vs radius, is there any way I can find the radius to get the best linear speed? The ...
4
votes
1answer
864 views

How to couple a motor to a screw drive?

I have a simple linear translation stage that is driven by a screw, and I would like to attach a stepper motor to the screw drive. The axis of the screw and the axis of the motor are approximately ...
3
votes
2answers
318 views

Pneumatic Actuators - System Reversibility. Is it possible to use an actuator to store energy?

I'm very much new to pneumatics and I was wondering if there was such a thing as a reversible pneumatic actuator? I'm designing a system that has to be lightweight, pneumatic and use a mechanical ...
2
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0answers
55 views

How are small refrigerator compressors started?

Small refrigerator compressors in the US generally all have exactly the same design and I am trying to understand their starting mechanism better. How exactly does it work? What I generally ...
1
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1answer
585 views

VFD/rheostat for motor speed control

I have a 3 phase motor and 3 phase power supply (400V, 50Hz) Currently this motor produces 1.5hp in torque and ~1750rpm. I need it to produce less. My question is: Is the best way to go about this, ...
7
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1answer
114 views

Which is more durable in sandy desert conditions: electric motors or hydraulic pistons?

If we have a tracking system placed in a tough desert environment with occasional sandstorms and temperatures that go as high as 50C, which actuator would be better: a hydraulic piston or an electric ...
1
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0answers
359 views

Gearing for Multiple Forward / Reverse on Single Drive Shaft

This model illustrates my question: Red is a motor Green is the drive shaft Orange are nylon straps Blue are spools for the straps I want to be able to drive multiple spools in multiple directions ...
6
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4answers
3k views

What is the use of gears in a device with a fixed gear ratio?

From my understanding, there are two uses of a gearing system: to change the speed of output rotation (trading it with torque), and to change the axis of rotation. Now, in a car, for example, it is ...
3
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3answers
2k views

How can I apply a load to an electric motor to simulate realistic conditions for an experiment?

I am trying to perform some experiments with a motor and I want to run it under realistic conditions (or at least not unloaded). Is there an easy way to load a motor? A couple ideas I had include: ...
1
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2answers
76 views

How do you mount a polystyrene foam wheel to a motor?

I have a wheel I CNC milled out of foam and I need to mount a motor to it. I designed and printed a part that would attach the motor to the foam, but I anticipated that the wheels would be wood back ...
5
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3answers
920 views

What would happen if we tried to run a motor in space when it is not attached to anything to provide support to it?

I know that when a motor runs it generates torque and that torque can be used to do useful work. On the other hand, the motor needs strong support that absorbs the reaction torque. In our case let us ...
13
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2answers
3k views

What is this small rotating part from a cell phone?

What is this tiny rotating piece of hardware that I found inside my Samsung GE1202? It has E9C written in blue on it.
2
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1answer
2k views

How do you calculate the best gear reduction for max speed?

I know that a gear reduction would decrease the RPM if the motor ran at constant speed, but in reality its speed is a function of the load. I first tried turning a wheel with a direct drive system, ...
2
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0answers
312 views

Upgrading to a brushless motor

I have a mini-lathe with a 500W 3/4 HP variable speed motor, that is run by a controller at two different gearings. However, even at the LOW gearing I find the torque to be a little inadequate. Is it ...
0
votes
1answer
1k views

What affects an internal-combustion engine's efficiency?

For a gasoline internal-combustion engine, used in accordance with the manufacturer's instructions (specified quality oil, fuel, etc. used), what changes the efficiency of the motor? For example at ...
4
votes
1answer
2k views

How to calculate if a motor is strong enough

I am building a machine for a project that should slowly tip a screen forward about 95 degrees, hold for a couple of seconds, and then slowly return to vertical. The design I am working on uses two ...
11
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1answer
576 views

Avoid snapping an electric cable from too much rotation

I recently built the basic construction for a crane out of lightweight material. Basically the head of the crane contains an electric servo motor which spins the head of the crane by pushing itself ...
1
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0answers
236 views

How can I choose a motor for my project? [closed]

I'm working in a project that consists of something similar to a motorized skate. I know how to do it, but I don't know what motor to use. I need that the skate to be able to move 90 Kg to 20 Kph (12 ...
1
vote
1answer
52 views

Is there a universally accepted way to refer to choosing a more powerful motor for an application?

One antonym word I can think of is "derating". If I say "derate motor for pump X", it can mean "select a motor with lower power output, since the pump doesn't need a more powerful motor". But what ...
8
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2answers
1k views

Air compressor that doubles as a pneumatic motor?

I am working on a compressed air energy storage system. The size and weight of the system are heavily constrained; nothing should (ideally) exceed a few pounds. For this reason, I would like to store ...
6
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5answers
17k views

What is Starting Torque?

I'm having a hard time finding an answer from the internet. What does starting torque mean?
2
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0answers
93 views

Validation of transfer function

I have developed a second order transfer function model for a permanent magnet dc motor in terms of speed and voltage. I had performed open loop no load experiments on the dc motor and derived the ...
6
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2answers
1k views

Why does public transport uses compressed air to open doors instead of electromotors?

System with compressed air seems more expensive and harder to build and integrate neither using simple electromagnetic drives to open public transport doors.
2
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2answers
1k views

How to calculate the steps needed for a motor to rotate a circular object in a pulley configuration?

I have a stepper motor with 200 steps per revolution and a pulleys configuration as following: 3 pulleys with 100 mm diameter each on 1184 mm PCD and are equally spaced (120 degrees) from each other. ...
5
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1answer
327 views

Power and motor current

This is a follow up question to my question here about torque and stepper motors. There Olin explains: Note also that torque isn't the only criterion for a motor. Power is another important one. ...
16
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1answer
50k views

Understanding required torque for a motor lifting a weight

This is a continuation of me trying to understand torque and stepper motors in my other question. I'm trying to understand the torque a motor would be required to generate to lift a small weight, and ...