# Tagged Questions

Speed is a scalar quantity referring to the rate at which an object changes position (but is not position-sensitive).

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### How does the number of poles in an induction motor determine its speed and torque?

I notice that the higher the number of poles, the slower the induction motor spins. Likewise, the lower the number of poles, the faster it spins. How does the number of poles affect its speed? Also, ...
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### Equalizing motors speed for balancing robot

I am currently working on a balancing robot project using Arduino Uno. I am able to get the robot to balance but one of its motor have the tendency to rotate more than the other. I am using the ...
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### Speed and torque calculation of stepper motor

The bipolar geared stepper motor I am planning to use has a resistance/ phase of 8.5 ohms per phase, inductance of 2.14mH per phase , normal current per phase is 2 amps, holding torque of motor is 0....
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### Increases in power

I have an electric scooter which I would like to boost or mod for more speed. Currently it runs on a 1600w 48v controller, but what would happen if I changed the controller to a 2000w 48v one, what ...
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### A question about a speed-controller

I need to use this controller with an external applied voltage to control a fan: http://docs-europe.electrocomponents.com/webdocs/1394/0900766b81394cac.pdf Currently it is controlled manually by a ...
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### Low rpm, high power calculations help

Im trying to build an electric wheelchair with mecanum wheels, and as you might know, each of its 4 wheels has to be independently powered for the chair to have holonomic motion. With my desired ...
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### Regulate FAN voltage from another potentiometer (Different voltages)

Currently i have a 100w LED been powered from a 14.4V lipo battery. I use a Voltage Booster to boost voltage up to 33V. I have modified the voltage booster with a pararel potentiometer to change LED ...
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### Why are relatively simpler devices such as microcontrollers so much slower than CPUs?

Given the same number of pipeline stages and the same manufacturing node (say, 65 nm) and the same voltage, simple devices should run faster than more complicated ones. Also, merging multiple pipeline ...
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### reducing input voltage to motor

I have a hypothetical question about running a DC motor on lower voltage than it is designed for. Lets say I have a 2hp 100VDC (yes, Direct Current) motor that I want run on 12 VDC. The motor is 2hp =...
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### Can a single potentiometer be hooked up to multiple fans to control their speed?

I have recently learned about potentiometers and their "variable resistance" porperty. I am looking to hook up a Potentiometer in order to control 4 12VDC Fans. I am not sure if that is a good idea, ...
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### Making a two speed motor - TRIAC and PWM question

I would like to create a dual speed blower which goes into HI when an SSR from a PID is activated. I would like to be able to control the speed of each of the high and low settings. When the SSR is ...
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### varying run capacitor for speed control of single phase motor

If I want to vary speed of single phase electric motor within say, 10 to 20%max of its rated speed ( or torque ), is it a good idea to change its run capacitor setting ? ( either via multiple ...
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### Efficient Single Phase Motor Speed Control

Usually triac based speed control vary the phase angle of firing to reduce the amount of power goes in to motor, and hence control its speed. this is not very efficient method, also it may not be good ...
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### How to measure speed without any mechanical or electrical connection?

I would like to build an as-much-portable device for measuring the speed of a vehicle, to check speedometer accuracy and know the offset if one present. The idea is a cigarette pack sized box one can ...
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### Speed of Synchronous motor determined by frequency, but how about current?

The speed of a permanent magnet synchronous motor is determined by n = 120f/p where f is frequency, n is speed in rpm and p is number of poles. p is fixed in a motor so changing the frequency ...
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### Building a PWM circuit to control a 90v DC motor at 20amps. Will this work?

Sharing the load among 4 transistors with ballast resistors -
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### Throughput and speed of data transmission cables [duplicate]

What are throughput and speed limiting factors in an ethernet or any other type of cable which is used for data transmission?
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### How to measure speed of a ball

I have small box (10cm x 10cm ) and I need to measure speed of ball (r=2cm) getting inside. I assume there are at least two possible ways. Put a sensor inside the box in point A and second one ...
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### Alternator shaft speed

I am running an alternator with an electric motor (variable speed), but I do not know the shaft speed. I would like to calculate it from voltage frequency. The rotor of the alternator has 12 poles (6 ...
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### Difference between nominal speed and idle RPM of a DC generator

I am currently studying for a electrical engineering related exam and came across this problem. What exactly is the difference between the nominal and idle RPM of a DC generator, and which one is ...
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### How can we compare processing times of two designs implemented on different FPGAs? [closed]

How can we compare two different designs that perform same task (e.g. processing a 256x256 image) and both implemented on different FPGAs, in terms of processing time(seconds)? For example one of ...
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### Reading car speed sensor (SDV)

I've been trying to interface with my car's info screen, called a TID (Triple Information Display), from Opel. From the factory, there are multiple things attached to this screen, one of those a line ...
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### Car speed sensor to turn on something [closed]

Is there a sensor for the speed of the car that can be programmed to turn on something when a car reaches to a specified speed? If yes, what is it’s name, and whare to find it online?
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### Synchronous motor base speed calculation

I would like to ask the following question. How can I calculate the base speed of a Synchronous motor for variable speed applications controlled in dq frame? I want to calculate the base speed for ...
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### General purpose cpu as logic analyser better / worse than dedicated FPGA implementation

This question relates to building a cheap but capable logic analyzer. I had the idea of using an x86 cpu that was running a program that could fit in the fastest cache that would just read data from a ...
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### BJT pre-biased arrays slower than discrete?

I've got a circuit that works - it's job is to convert a TTL square wave into a +/- 12 volt square wave. simulate this circuit – Schematic created using CircuitLab Note that the ...
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### Is moving fast will effect WiFi transceiving beavior?

Let's say I'm driving a 2010 Bugatti Veyron 16.4 Super Sport, with speed of 431 km/h = 268 m/h = 119 m/s Now I have a WiFi signal receiver installed on the top of the car and a WiFi transmitter in ...
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### Ceiling fan speed control

I have heard it said that a ceiling fan with a built in three speed manual switch should be set on the high speed setting when using an electronic speed control. I have not found an answer as to why ...
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### Get current gear from rpm and speed through OBD2

I would like to modify my car with the help of Arduino to display the current gear. I wasn't quite sure where should I post this question as it is a car topic, as well as an electric engineering and ...
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### Difference between torque and speed in dc motor?

I have knowledge about the definitions about both speed as well as of the torque. But I am unable to think dc motors in terms of speed and torque. When the armature of a dc motor rotates , we call it ...
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### BLDC speed/torque control with L6229 or L6235

I'm trying to control 12V 12,000 rpm BLDC motor with 3x120° Hall sensors using ST evaluation board based on L6229 IC. I tried to control motor's speed by feeding PWM to FWD/REV pin as suggested in ...
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### What components or circuitry exist that can provide extremely high speed, accurate clocks?

I've been curious for awhile now about doing some high speed projects, such as measuring time differences of radio wave reception, and was wondering if there exists components that provide clocks much ...
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### Accelerometer double integration error

I wanted to use an accelerometer or IMU to measure speed and displacement over a period of about 1 minute or 400m. From this answer I found at stackoverflow, the error propagates at a rate of $t^2$ (...
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### What's the best method of measuring displacement and speed without resorting to GPS?

Is it possible to determine the displacement, speed and acceleration of someone while running, by using methods like dead reckoning, sensor fusion or other, and sensors like accelerometers, ...
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### AC Motor operating region

I've been using an ABB IRB 2400 robotic arm to gain experimental data and write a report based on the data. I found that when I operated it at different speeds for pre-programmed paths, I got a ...
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### Measure the speed of a stationary bike with belt drive

I have a problem with the measurement of the speed of my stationary bike. (also here) Parameters: radius of flywheel is 13cm second wheel is 12cm (0.12m) the sensor is simply a reed switch I'm ...
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### Electron speed in resistors

What affects the speed of electrons in a resistor? If two resistors are connected in series, they both have the same current ; same amount of electrons passing at a point per second. Then if one ...
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### Calculate Speedup

What is the overall speedup of a system spending 65% of its time on I/O with a disk upgrade that provides for 50% greater throughput. The formula should be Amdahl's law: overall speedup = 1 / (1 -...
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### How to run a 6v 4amp motor at slower speeds for long periods of time (2 hrs)?

I am trying to get a project done for Halloween. I am running a 6V 4A motor (from a powerwheels) but need it to run slower. I tried using an adjustable charger and ran it at 3V to slow down the ...
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### How does the bandwidth have something to do with speed

They are saying that, if the bandwidth of a certain device becomes narrow, then its speed decreases. However, how does the speed has something to do with the bandwidth? If you are saying that the ...
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### Ethernet: Why is the link status “down” when there is a speed mismatch?

For any networking (ethernet) equipment, the link status (layer 1) is down when there is a speed mismatch between two ethernet interfaces (say: one is 10 Mbit and another is 100 Mbit). Is it ...
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### Slow down stepper motor's speed using stepper driver DRV 8825

I've got a Nema 17, rated at 0.8Amps, stepping angle of 1.8 degrees. The motor looks like this, and has six wires coming out of it: The four wires I've used are the ones labeled below (I was ...
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### Capacitor bank with variable speed motor

I have a set of three pumps (power ~100 kW) with variable speed AC motors and I would like to know the best option(s) to reduce the cost of reactive energy. For instance, would it make sense to ...
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### FTDI communication speed

How can I get very high speed from a FTDI chip? I have tried with FT232RL with UART in 230.4kbps but I want much more than this. Will I need some other different speed?
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### What type of motor can provide smooth motion at low speed around 0.1 to 1 mm/s

I am building a stage for tissue cutting and the motion of the stage should be very slow and smooth. The speed range is 0.1 to 1 mm/s. I got a stepper linear motor from PI (M230.10s), I test its speed ...
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### Why long pipelines are preferred over high CPU clock?

Why modern CPU vendors prefers increasing the maximum length of the pipeline over increasing the clock? Accordingly my understanding, increasing either increases the number of gate switches and so ...
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### Speed and Position Control for high-volt Elektro Motor with AVR

Is there anything that one can purchase to control speed and position of a high voltage electro motor? I am quite a bit of a noob at this but I could think of a circuit using photo-sensors or hal-...
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### What's the maximum CAN bus frame (message) rate at 125 kbit/s?

My CAN bus is running at 125 kbit/s and is using extended frame format exclusively. I would like to know what's the maximum rate of CAN frame I can send out. Suppose the data length is always ...