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Questions tagged [speed]

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

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Measuring BLDC Motor Speed with Angle Feedback

I am trying to implement FoC for a BLDC motor. I have a dedicated control board(STM32H7) that receives current and angle feedback, but I'm having trouble figuring out how to measure the speed from the ...
Haoming Mei's user avatar
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1 answer
48 views

Speed control fan with PWM and capacitor (no pwm fan)

For my project I want to control the speed of a regular non-PWM fan. I was wondering if what I came out with is a good idea or not. I noticed that the capacitor I used (25V 47µF) gets a bit warm after ...
DeltaLima's user avatar
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Variable speed drive for an alternating current motor with PIC18F4431

I'm designing a control board for a three-phase motor speed controller using a PIC18F4431. I've used an inverter powered by 24V DC to convert the voltage to 24V AC to power the motor. Additionally, I'...
embar's user avatar
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Wire the ALPS RWM SCS Speed control Switch

I recently purchased an ALPS RWM SCS Speed Control switch board. This will speed control an ALPS Standard Rod Wrapped 110 VAC motor . The board has. B500k POT, capacitor, resistor and TiAC components ...
Russ Amato's user avatar
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PWM for 48V Brushless DC motor control

I am converting a lawn mower to electric motor driven. I have a 1800W 48V 26A brushless motor. Rated speed is 3000 rpm. I need to run it at 1800rpm for direct drive. From other conversions I have seen,...
Dougiej's user avatar
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Highest speed of operation [BJT vs MOSFET] [closed]

This question was asked in a competitive exam in India. Which of the following offers highest speed of operation? (a) BJT (b) FET (c) Enhancement Mode MOSFET (d) Depletion Mode MOSFET As far as I know,...
MAJID AHMAD's user avatar
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Is there a set procedure you should follow when you have three adjustable potentiometer that you need to make adjustments to [duplicate]

The question I posed is to do with a project I am working on, It comprises of a 24V D.C electric motor, 200W, 3,000 rpm, 13A. which drives a drive shaft via pulley, and belt, on the shaft is a ...
Drew1815's user avatar
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Need a support to find out "how fast the MOSFETs (Sie882DF) can switch"

I am using Power MOSFET from Vishay part number Sie882DF to operate at linear region, Following are the steps I have followed to determine the switching speed, Datasheet electrical spec: Sie882DF ...
Ram_HW's user avatar
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Using blind vias for fanouts in GND and power planes

I am designing high density board with high pins count BGA, and hundreds of decoupling capacitors, in that what are the recommendations for using blind vias for fanouts to connect power and GND planes....
Jweta's user avatar
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Is it safe to replace a 120ns Flash memory with a 90ns part?

Here is an old PLC board with a pair of AM29F200AB-120SI SOP-44 256kB 5V flash chips. One is unable to retain data, after nearly three decades in service. These are very challenging to find today, ...
rdtsc's user avatar
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Phase velocity expression

We have a \$\beta l\$ expression which is represented as phase velocity. I know \$\omega_o=2\pi f\$. What is the exact expression for phase velocity used in here?
lub2354's user avatar
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Can you design a DC motor with any arbitrary torque speed curve?

Title pretty much says it all. I have a low-rpm (30-160) and moderate-torque (2 N-m) application. These characteristics are pretty easy to hit with an off-the-shelf dc motor + gearbox. But let's say I ...
user3010936's user avatar
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BLDC torque and speed control

Actually I drive a DC motor in speed and torque at the same time. I would like to know if there is a solution to do the same with a BLDC. The motor is 50W max. I can make a custom PCB to use a BLDC ...
DECORME Sébastien's user avatar
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Need help figuring out how to organise a system to run a stepper motor at low speed without Steps-skipping

TL;DR : How to prevent step-skipping with a NEMA gearbox motor at low speed. Edit: following @glen_geek comment, removing the load on the system seems to remove the problem, hinting at inertia and ...
Guillaume_slize's user avatar
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How much lower than the ideal torqe curve is the actual torque of a PMSM running at overspeed?

VFD-controlled PMSM's are said to produce constant maximum torque up to the rated speed. Above the rated speed the VFD performs defluxing and produces constant power. This should then mean that at 200%...
K0ICHI's user avatar
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Synchronous motor: intuitive explanation of f = 120/PN

In synchronous motors, let f be the frequence, P the number of poles and N the number of tours per second: $$f = \frac{120}{PN}$$ I don't understand this relation at all. In my opinion, the more ...
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Slowing down 3-speed ceiling fan

I have a 120 V, 60 Hz, 3-speed ceiling fan. The capacitor is a 4-wire one with the following value for capacitor E183963 CBB61: 5 μF +/-5% 250 VAC = Yellow 5 μF +/-5% 250 VAC = Purple 4.5 μF +/-5% 280 ...
Ben's user avatar
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4 votes
3 answers
2k views

DC motor spins faster in reverse

Due to certain circumstances I need to run my brushed DC motor in reverse (positive to black wire, negative to red wire). What I noticed is that when set up this way running at no load requires 1.5A. ...
php_nub_qq's user avatar
3 votes
2 answers
474 views

Ethernet speed issue

We have made a customized harness cable for Ethernet communication as shown in the attached image. Here we are facing an issue with communication speed. Whenever we use the below cable, we get only 10 ...
Chitharanjan's user avatar
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2 answers
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Mimimum time required for an NMOS transistor to operate as a switch?

How do I calculate the minimum time required for an NMOS transistor to work properly as a switch i.e. in the triode region? When the time period is very narrow, the switch might not turn on and our ...
negative_feedback's user avatar
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1 answer
954 views

Why does this DC motor increase in current and then decrease as the speed increases?

Well, the general answer to this is that as the motor needs to overcome the inertia from its state of rest, it requires high starting torque and aka high current is consumed to do that work. On the ...
venkatesh nayak's user avatar
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126 views

Adding variable speed control to 3-speed bldc pool pump motor

I have several 1.5 hp 240 V bldc pool pump motors I've repaired and salvaged from work with plans to re-purpose them on certain projects, an upgraded high torque motor for my mini lathe being a good ...
Anders 's user avatar
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360 views

Electrical torque and electrical power of a generator?

Having the electrical torque and the angular speed of a synchronous generator, can I calculate its electrical power output as the product between the electrical torque and its angular speed w (Pe=Tew) ...
Samuele Benito Di Gioia's user avatar
1 vote
1 answer
2k views

Maximum speed Nema-34 stepper motor can handle

I've got used 34HS8801 NEMA34 stepper motor which I am experimenting with. Unfortunately, dtasheet doesn't provide driving voltage, nor does it provide maximum RPMs. Now, I would like to see how fast ...
seeker's user avatar
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2 answers
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What is happening when a motor is set to a "high" speed?

When looking at different electrical devices like a blender, vacuum cleaner, fan, or drill, it's common for these devices to have different speed settings like "low" or "high" or ...
Cheesy Life's user avatar
1 vote
1 answer
1k views

Can you control BLDC motor speed with PWM?

I wanted to control the speed of a very fast and noisy brushless dc cooling fan. The fan I have is a 3 pin 12v 6.3w 120mm fan by Delta Electronics. From what I've learned from the internet is that the ...
Kokachi's user avatar
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STM32F334 Nucleo-64 ADC speed

I have a problem with my ADC speed. I'd like to have a speed over 1 MSPS but I get only 60 KSPS. I use a very basic code that uses ADC interrupt to stock the value into a table and when the full data ...
Ats's user avatar
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Quick state feedback controller question

If two estimators where used in a state feedback system, one with error dynamics poles at -10 and -9 and another one at -80 and -90. Which system will give you a better overall performance?
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How to judge my achievable design frequency on FPGA?

I am coding a design from scratch in VHDL. The FPGA target is a Cyclone V. My design resource occupancy is around 30 % of Logic. I able to reach a frequency of around 80 MHz. The worst paths are ...
dsp_curious's user avatar
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3 answers
433 views

Measure ball speed with sensor inside

I came across a product which is a ball with a small Bluetooth sensor placed inside. This sensor, coupled with an app, can measure ball speed, height and length of throw. I wonder how this is possible,...
neting.it's user avatar
0 votes
2 answers
169 views

How are real-time speed and torque of a brushless DC motor computed?

Let's suppose I need to work with a three-phase brushless DC motor. The DC motor has only three wires to control its 3 phases, there is no other wires (no Hall effect sensor return for example). ...
JackOfHearts's user avatar
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44 views

Exciting the rotor and stator of a slip ring induction motor at different frequencies, will it develope torque?

I came across this question as I was preparing for an exam, I am unable to understand the theory behind it. The textbook says the motor can run a 600 and 2400 rpm but gives no explanation. Could ...
User's user avatar
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What is the effect on speed and power when we connect three motors on a single shaft? [closed]

Rolls Royce used three 750R (YASA) motors in their aircraft "Ionbird." All motors are mounted on the same propeller shaft. What is the effect on the overall speed and power of the motors? ...
Atul Futane's user avatar
1 vote
2 answers
201 views

High frequency BLDC control for parallel speed and position control. Looking for thoughts

I was not able to find a similar topic but am kind of stuck with my problem. What am I doing? I am trying to control the speed of a BLDC Motor very precisely but have to control the position of the ...
sebbe's user avatar
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0 votes
2 answers
513 views

DC motor coupled to a DC generator

Consider a separately excited DC motor which is coupled to a shunt dc generator (under no load condition) and acts as a prime mover. If we set the speed of the DC motor to some certain value (for ...
S.H.W's user avatar
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3 votes
3 answers
707 views

Replacing a 3-phase speed-varying drum switch with a VFD?

I am working on a stock feeder / power feeder (used with woodworking equipment). It has an 8-position drum switch to control both fwd/reverse direction as well as vary the speed. The ON positions of ...
StayOnTarget's user avatar
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3 votes
1 answer
1k views

Controlling the speed of a single phase 4-pole induction motor

I have a Crompton Greaves single phase induction motor that powers my drill press (image below). I believe it’s rated at 1/2HP. I wanted to control the speed of this motor so that I can use the drill ...
user3418620's user avatar
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12 votes
1 answer
477 views

Speed of compound wound dc motor

This is homework. Given a 500W, 200V compound wound motor with constant shunt field and a series field that varies with armature current, how do we calculate the change in motor speed. I know the ...
sunra's user avatar
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0 votes
1 answer
153 views

Engineering basic question: speed of a device designed in FPGA [closed]

I am studying FPGA by myself, sorry if it is a stupid question for you. I am going to design a block in FPGA ( vivado/vhdl). This block will transmit data. I need to reach for this block, for example ...
Franki Lee's user avatar
0 votes
1 answer
102 views

Tachometer frequency problem

I have an NPN tachometer sensor. I want to measure the rotation speed of a three phase motor, but the output frequency of the tachometer changes. For example, if the actual value of the motor ...
macrobert's user avatar
-1 votes
1 answer
82 views

Throttling of Electronic Speed Controller with 6S lipo

Thanks for having look at this. I had an turnigy 150A ESC and 2000KV bldc motor. I calibrated ESC and it happened perfectly. I connected 3S lipo to ESC and increased the throttle from 1100uS to 2000uS....
pavan g's user avatar
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113 views

Single phase motor does not stop

I have a circuit that controls sine phase motor with three triacs. When I turn it on it works properly, I can regulate the speed, but when I turn it off the motor does not stop, it still spins but not ...
Sciart's user avatar
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0 votes
2 answers
110 views

Display the speed of a Dc motor [closed]

I have an industrial rotating machine (huge dimensions) working with a DC motor, there is a button that changes its speed but the value of this speed is not displayed. is there a circuit that measures ...
Moro123math58's user avatar
0 votes
1 answer
699 views

Can I lower speed on 1/4 HP PSC fan motor by lowering the input voltage without harming motor?

I have pics of the motor label. This motor now has three speed settings: low, medium and high. I have pictures of the control as well.
RAD's user avatar
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0 votes
1 answer
88 views

Not sure about the way to compute the voltage across a DC motor driven by a NPN BJT

Long story short, I wanted to make my own H-bridge but I was out of p-channel MOSFETS so I tried to design one with BJTs instead, but before doing just that I simply wanted to try to run an average 3-...
tampler's user avatar
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1 vote
1 answer
182 views

How to get fine DC brush motor speed regulation?

I want to get a fine speed regulation of Pittman DC 24 V brushed motor with 10,000 RPM for a hobby project. The voltage I will use is battery 12 V DC, so does that mean the speed will be 5,000 RPM? I ...
Paul's user avatar
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0 votes
0 answers
372 views

Why the speed and current will decrease when I change the connection delta to star on ac motor?but reduce motor voltage will have opposite result?

On the 3phase motor, The motor has been accelerated to a stable operating speed, then I reduce the line voltage -> speed decrease -> slip increase -> current increase -> the power will ...
Hiu Fung Kwok's user avatar
-1 votes
5 answers
162 views

Alternating current frequency

An introductory discussion of alternating current in a primer I was taking left me thinking. We don't see a light bulb flicker because the alternating happens at 50-60 Hz. If it takes 1.28 seconds for ...
Ivan 's user avatar
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0 votes
1 answer
112 views

Expected SDRAM access speeds?

I would like to get an idea of how fast SDRAM accesses should be. If I have a 32-bit ARM based processor running at 500MHz accessing an SDR sdram device clocked at 166MHz, what sort of read/write ...
Ronnie Shipman's user avatar
1 vote
1 answer
354 views

What is the value of this resistor?

I am trying to fix a rotary tool's AC powered DC motor controller, there is a resistor that has been burned out, I want to replace it for a new one, my question is how do I find the value of the ...
bran's user avatar
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