Tagged Questions

A common actuator in robotics; it's usually made of a static magnet (stator) and a set of moving inductors, acting as electromagnets, connected to the circuit through brushes. Brushless motors use phased clocks with electronic circuitry to generate motion.

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3answers
40 views

HEXFET PWM motor driver does not work

I'm trying to drive a motor for an academic project, using the circuit in the image. The STM32F4 Discovery board that I'm using in this phase of the project produces a 30Khz PWM at 3V, that is correct ...
0
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0answers
53 views

Arduino with 6 motors controlled by Android device

For our first year engineering project, we are creating a guitar tuning device. We will need to control 6 motors, each turning a small knob (<1 inch) against a 10-20kg string tension. Manually ...
0
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1answer
63 views

High Torque Brushless DC Motors in Small Package

I have a particular set of requirements that call for a relatively high stall torque for the space available (300 ozf-in for < 8cm length of motor). The motor would be operating at a relatively low ...
9
votes
3answers
567 views

Locking up a DC motor with constant supply a bad thing?

I am working on a little pen plotter project and for one of my motors (which supports the pen) I have used a small DC motor obtained from an old DVD drive. I have noticed that if I supply a constant ...
0
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0answers
79 views

How Can I Slowly Turn Container With Electric Motor

I am wanting to slowly turn a jar in the horizontal position -- like a hot dog at 7 eleven, only no heat or stepping required. The idea I currently have is to use 2 dowel rods with a low RPM DC ...
0
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0answers
90 views

I think I have burnt my 24V DC motor

I had a 24V DC motor connected to a Polulu motor driver which was connected to an arduino uno board. I accidentally connected a power supply instead of a volt-meter to both ends of the motor while in ...
5
votes
5answers
271 views

Can a motor's movement be improved to any arbitrary resolution?

For a project that I'm working on, I need motor rotation at extremely small increments -- my desired resolution is about ~0.15 degrees per minimum rotation step. Of course, most motors of reasonably ...
0
votes
2answers
127 views

How do you control 130-size DC motors with an Arduino (seemingly 20A DC motors)?

I'm a little confused on specifications and limitations here... I have 3 (130-size, I believe) DC motors I'm attempting to control with an Arduino. They are running off of a 7.2V NiMH battery pack, ...
0
votes
1answer
63 views

Am I misunderstanding the specs of this solar panel or electric motor?

I've been trying to figure this out, but the answers I've come up with thus far have been counter-intuitive. The solar panel's specs are as follows: ...
0
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2answers
68 views

Convert perpetual magnet motor output to 5 volt DC

Disclaimer: Hi, I was in the neighborhood (StackOverFlow) and just noticed this cool site. I have had this general wondering for a while now and I am not sure if my question is constructive enough for ...
0
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0answers
28 views

Can DRV8837 be used to drive two DC motors in all four ways?

Knowing that some motor drivers do not perform well under low input voltages, I have found that this works well; but how do I drive motors in the following four ways: ...
3
votes
1answer
114 views

Brushed DC motor control MOSFET selection

I want to control a brushed DC motor of the below specification: Motor: Permanent magnet DC brushed motor Voltage: 180V Current: 5 Amps RPM: 1500 The control method is PWM switching through a ...
0
votes
0answers
30 views

Power Supply Requirements [duplicate]

I am building some prototypes for my thesis but I am not sure how to buy the power source for them. I need to how to choose a proper power source(Volts, Amps, etc). The number of motors will vary but ...
0
votes
1answer
48 views

Using an H-Bridge like a comparator

I'm wondering if there's a way to use an H-bridge like a comparator- That is, if one input is greater voltage than the other, then the attached motor spins one way, and vice versa, and it doesn't spin ...
3
votes
4answers
634 views

DC Motor + 9 V battery + 270 ohm resistor = Nothing (Motor won't turn)

I'm trying to wire up a DC motor to a 9-volt battery with a resistor in between, and the motor just won't turn. It works if I connect the motor directly to the battery, but not with the resistor in ...
0
votes
1answer
56 views

How can I use 15 servos with arduino mega2560 without stepping down voltage?

How can I use 15 servos with arduino mega2560 without stepping down voltage? because I want to control 15 servos by one board (arduino mega 2560).
0
votes
1answer
77 views

Using a brushless DC motor for generator

Is it possible to use a brushless DC motor as a generator? If we use the brushless DC motor in the following configuration, the brushless DC motor is used in front wheel of a rover/small car, and the ...
0
votes
1answer
57 views

Controlling high rating DC motor

In a robot, I need to use a (24 volts 5-7 amp) DC motor, which should be controlled by a microcontroller. Now, will I get a motor driver IC for such a motor? If not, what kind of circuit will help? I ...
0
votes
0answers
45 views

Variable Performance in DC Motor, Arduino, and L293D?

I have a pretty typical set up with an Arduino, a simple DC motor, and an L293D breakout board. I am using PWM to control the speed of the motor into the L293D enable pin. The DC motor is driving a ...
1
vote
2answers
289 views

Why would I need a relay between a DC motor and my Arduino?

I was told that I should put a relay between my 5V motor and my Arduino. I asked why, but they didn’t know. Why do I need to separate them with a relay? The motor requires 5V and the Arduino provides ...
0
votes
2answers
55 views

Best way to step down (half) battery voltage for motors

I have a 4S LIPO battery 5800mAH at 14.8V and I want to use it to power some 7.2V motors I have. The Rover 5 Chassis to be exact (https://www.sparkfun.com/products/10336), the only problem I have is ...
1
vote
1answer
31 views

PMDC Motor transfer function

I'm doing an analysis of a PMDC motor and I don't understand something about the transfer function. I have the following equation: \$(K_t\frac{1}{((s* L_A) + R_A)})(V_I(s)-k_b\omega(s))= ...
-1
votes
1answer
25 views

Cumulatively excited and Differentially excited DC generator

Is a cumulatively excited DC generator long shunt or short shunt motor?
1
vote
1answer
90 views

Why can't we command two DC motors with just 2 relays for each in opposite directions with a same power supply? [closed]

We managed to control 2 DC motors with 2 relays for each one.It worked great except one thing: we couldn't make them turn in opposite directions at the same time .We noticed that there was a shot ...
0
votes
0answers
48 views

Create a negative volt with a 9v battery to run a 18V motor

I've got to create a small toy car running on a 9V battery to participate on a small race of 2x 15m and would like to use a bigger motor running on 12-18V. If I'd create a negative voltage it should ...
1
vote
2answers
131 views

Using the same power source for microcontroller (arduino) and rest of the circuit?

I have an Arduino, it controls a 6V DC motor and 12V DC solenoid (which only really needs 7V for what its doing). Originally I wanted to use 1 rechargeable 7V battery (or 9 or whatever the closest I ...
0
votes
1answer
52 views

Using dc motor as a sensor

I am thinking about an automatic blind opener/closer. In this idea I need to detect the end of blind while opening or closing to stop the motor. I don't want to use mechanical sensors on both side ...
2
votes
1answer
84 views

Eliminate PWM noise in PWM-driven bidirectional motor

I need to drive a DC motor with PWM, through a H-bridge. The controller can't generate PWM at ultrasonic frequencies with resolution I desire, and the low-end of the spectrum (~100Hz) may be too slow ...
2
votes
3answers
65 views

Current drawn by a permanent magnet DC motor

I have been working with PMDC motors for a while now. In these motors, as the load increases current drawn by the motor also increases. I was just wondering what is the theoretical reason behind this ...
3
votes
1answer
90 views

Difficulty getting motor to reverse

I am building a humane rodent trap, and require assistance. The trap works using an LED (not shown) and LDR (photoresistor). When the rodent walks over the LED, The LDR increases in resistance and ...
0
votes
2answers
143 views

H-Bridge Instant Death

I have a DRV8840 that I am trying to use. I have burned up about 10 of them trying to get it working. For this application, I need the H-Bridge to Current Limit and Brake the motor. Max current ...
0
votes
3answers
123 views

Connecting diodes to a motor in H-bridge

I'm attempting to design a three wheeled toy that is controlled by a remote connected with it via a cable. I first designed it with relays, however I had to change to transistors due to contrast ...
0
votes
1answer
64 views

Transfer Function: State Space for DC motor

General question on making state space equations for a DC motor. In the link below, why are both the electrical and dynamics equations 3 and 4 used to make a state space eqn.8, instead of combining ...
0
votes
1answer
45 views

How to regen a DC motor from the high-side of a boost converter?

I am planning to drive a 24v motor from a 12v battery, using a DC-DC boost circuit to generate the 24v and an H-bridge to PWM drive the motor. A problem arises when the motor goes into the regen ...
3
votes
1answer
378 views

Why does the potentiometer burn up in my setup?

I connected a potentiometer to my DC power supply (max 1A, 12V), and then connected a motor to the variable voltage side of potentiometer as well. The potentiometer is just 1K. When I tried using ...
1
vote
2answers
344 views

limit switches to control motor direction

I am trying to use two limit switches and two DPDT relays to control the direction of the motor. When the power is applied the motor should rotate one direction (direction for this question isn't ...
0
votes
1answer
68 views

MOSFET controlled DC motor too slow

I want to control a DC motor using a P-channel MOSFET. I tried the motor with a 5VDC power supply. It works perfectly and speeds up in no time. I measured the current flowing through, it's around ...
3
votes
4answers
726 views

How to get more current from 555 timer?

My power supply is filtered regulated 5 volt 500 mA . I am using a 555 in monostable mode to switch the motor on for a certain amount of time after the 555 is trigerred. (The 555 is being trigerred by ...
1
vote
4answers
125 views

Control strong DC motor with microcontroller

Could anyone explain to me what it takes to control a strong DC motor with e.g. an AVR? For example if I have a 24V Motor with 5A or more. How can I build such a circuit? Especially if I want to ...
1
vote
2answers
137 views

How can I increase the torque, but not the speed of this DC motor to gear with a potentiometer setup?

Short video of the machine running. It's made of three AAA batteries in series giving a total of 4.5V to the DC motor, these are connected through a potentiometer to control the speed. The DC motor ...
0
votes
2answers
304 views

Cascading PID DC Motor Position & Velocity Controllers

I'm trying to build a robot with a differential drive powered by two DC motors. First I implemented a PID Controller to control the velocity of each motor independently. Estimated the TF using the ...
0
votes
2answers
87 views

Will brushless fan speed depend on amperage?

I am not a technical guy and have no knowledge in electrical subject. I use brushless fans in my regular day to day activity. We use them for pellet stoves and hence my question: Will amperage ...
2
votes
3answers
141 views

Is Back EMF relevant in dynamos, where there is electric generation?

While doing some research about dynamos, I came across a situation wherein there was a question about the validity of my dynamo design. The counter to the design I suggested was that there would be ...
1
vote
0answers
70 views

L293D causing motors to move slowly

I'm modifying an RC car to use bluetooth. I use the L293D chip, and when I connect the motor to the chip, the car barely moves. If I connect the 9V battery directly to the motor, it moves the car ...
3
votes
1answer
54 views

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 ...
0
votes
4answers
344 views

How to increase torque and decrease RPM of a DC motor?

The motor is an old one from a cassete player of some sort. I am powering the motor with a 9 volt battery, but it's RPM is too high for the desired purpose. I have used gears to reduce RPM but it is ...
0
votes
1answer
45 views

Selecting MOSFETs for Motor

I want to implement a driver circuit for a (sensored) motor that I am purchasing which has the characteristics (on the shopping website): Max Amps: 16 Max Power: 350W ESC: 35A KV: 1900 The ...
1
vote
1answer
41 views

PWM input voltage regulation

I have a 12V DC motor that I plan to run in one direction with PWM input at 21A. However, in the other direction I want to drop the voltage to limit the speed. Ideally. the regulator would sit between ...
-2
votes
2answers
212 views

130V DC Motor Control

I am interested in building a control circuit for a motor. More specifically this motor. The model I want to control is the 130V model, 0.48A, which should make it at ~62W for the motor, and 1/17 ...
0
votes
0answers
91 views

Do I need a resistor for powering a 3-12v dc motor with USB 2.0

I'm trying to make a project from instructables: http://www.instructables.com/id/ATtiny8545-POV-Display/?ALLSTEPS And the guy uses resistors for his usb cable and now I'm not sure if I need to use ...