Questions tagged [motors]

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3
votes
1answer
37 views

Design decisions for variable speed motor switch settings (vs., say, rheostats)

Why do some variable speed motor switches have the highest speed setting next to the off setting instead of the lowest speed setting next to the off setting? For example, most 3-speed household air-...
8
votes
4answers
802 views

How does load force impact load inertia?

I am trying to simulate a winch as a speed-regulated motor that works through a gearbox to lift a mass. The output of the gearbox is a drum, which rotates to accumulate cable. I feel comfortable ...
1
vote
1answer
315 views

Motorcycle Engine Vibration - Difference between left and right side

I measured the vibration (jerk) on the left and right side of different motorcycles. I tested different engine types: Boxer engine, 3 cylinder, and V4. I measured the vibration on the same route, ...
4
votes
1answer
259 views

What is the required torque to rotate a 50mm aluminimum plate of weight 100g?

I have a aluminium plate of radius 50mm and thickness 4mm. How much torque is needed to rotate it? In case additional information is required : I have a RS 380 motor, but I guess torque required is ...
2
votes
2answers
512 views

Torque sensitivity of a VFD induction motor through a gearbox?

I have an application that requires torque limiting and I need to determine if VFD torque limiting will provide sufficient protection. I have used VFDs for torque limiting through gearboxes before ...
2
votes
1answer
525 views

Do linear actuators need to stay powered once in place? If not, how can I lock them?

I want to build a small remote-controlled submarine, and have been thinking about how to handle the ballast tanks. The simplest option seems to be a piston shaft, which fundamentally needs some kind ...
2
votes
1answer
43 views

What happens if current provided to mono phase motor is less than rated power

I have a 0.5 kW single-phase AC motor. What happens if the supply is 220 V but can't supply the full current needed? Will the motor torque be lower? Or will it be slower? Will it be any ...
1
vote
2answers
90 views

motor to move rope sinusoidally

I'd like to prototype a kind of device to move a rope like a sinusoidal, or similar waveform, it doesn't have to be precise about the waveform, the goal is hide this mechanism in order to show a ...
1
vote
1answer
821 views

DC brush geared motor: coast vs brake effects on motor/gearhead lifespan

I'm dealing with an application in which I use small DC brush geared motors to move a robot. The motors are driven by a standard FET driver. I do have the option to coast or brake the motor after ...
1
vote
2answers
3k views

Dc motors: relationship between PWM frequency and Torque

I am experiencing serious reduction in torque when using PWM to reduce speed - I'm temporarily resorting to 10Hz, and even then, 50% mark-space gives me (at most) half the torque of fully on. I'm ...
1
vote
1answer
230 views

Stepper motor holding torque without coils energized?

I want to know what torque a stepper motor can hold when stationary. They seem to only have one figure in specifications for holding torque which, I presume, is while coils are energised. How is ...
1
vote
1answer
364 views

Is there a more efficient transducer to convert mechanical energy into electrical energy than electromagnetic induction? [closed]

I know piezo film has one of the lowest efficiency to date when it comes to converting mechanical energy (or stress in the context of piezoelectricity) and motor (magnet and coiled copper wire) seems ...
0
votes
1answer
153 views

MMF in AC windings

I have recently studied that the mmf produced by the stator in an electrical machine varies as a rectangular wave over the air gap periphery of the machine; And to make the wave similar to a ...
1
vote
2answers
173 views

Energizing of armature as function of position in electric motor

How is the armature in an electric motor energized (i.e. main conditions on signal as function of position)? Let's consider the following parameters: $n_a$,$n_f$ the number of armature and field pole ...
5
votes
2answers
126 views

How can I tell if a motor is defective?

I recently bought two 12 V DC motors from Amazon. After I received them today, I tried testing them. One of the two motors run fine but the other motor shows erratic behaviour. It gets very hot within ...
0
votes
1answer
1k views

Relationship Between Gear Ratio and DC Motor Power Consumption

In my class, we are currently trying to understand the relationship between gear ratio and motor power consumption. Given two gears, one attached to a motor, and the other attached to a string ...
3
votes
3answers
658 views

Can Fast Fourier Transform be used to monitor for fault vibrations in a hard disk?

We want to monitor hard disks for present problems or pending failure. Can the Fast Fourier Transform (FFT) of a given hard disk in question, then, be compared with a reference FFT for a perfectly ...
3
votes
1answer
152 views

What sensors should be used to analyze vibration of a hard disk?

What kinds of sensors can be used to monitor the condition of a hard disk? We want to be able to detect when a hard disk is not operating correctly. Unexpected vibrations may be caused by spindle ...
2
votes
1answer
5k 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
votes
0answers
46 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 (...
11
votes
1answer
963 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
110 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
votes
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
vote
2answers
856 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
155 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
459 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
vote
0answers
33 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
115 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
226 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
votes
4answers
69 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
136 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
180 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
53 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
473 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
votes
0answers
96 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
100 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
vote
0answers
111 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
votes
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
896 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
322 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
votes
0answers
56 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
vote
1answer
610 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
votes
1answer
116 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
vote
0answers
366 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
votes
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 ...