# Tag Info

### What is stall current and free current of motors?

All very good answers, but as a physics teacher I am concerned about some incorrect equivalences here that can only lead to confusion. One form of [energy][1], eg [chemical potential energy][2], can ...

### What are some ways to estimate torque/load on a robotic arm joint

Model Based: Low cost solution is always software: Develop a dynamic model which computes the load on the motors based on the motions (e.g. with Recursive Newton Euler Algorithm or Lagrange-Euler ...
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### Can too much input current destroy my motor driver?

You are approaching the problem from wrong side. Current capability of a battery (25C) has nothing to do with that how much current will it actually source. It is the load (motors in that case) what ...
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### Can't Read current on Pololu Dual MC33926 Motor Driver Shield for Arduino

When there is miscommunications between the microcontroller and a chip, assuming the electronics are not damaged, there could be a couple of things that can go wrong. Of course, further diagnosis is ...
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### Inner current controller benefits

What would be the benefits of implementing this full nested control architecture for the control compared to my current implementation Textbooks are always a great source of information! Reference: &...
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### How to deal with current spikes due to fast direction-switching motor commands?

I've experienced a similar problem before. For me, the root cause was insufficient battery power. When my motor tried to draw peak power it caused the battery supply bus to brown out. This led to ...
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### How to deal with current spikes due to fast direction-switching motor commands?

As explained in my answer to What is stall current and free current of motors? when switching direction on a motor, you can end up drawing more than the maximum normal current rating. This can cause ...
• 4,088
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### Power switch standards and suitability for purpose

First, regarding why “the same switch can be rated for different amperages”, the current-rating of a switch depends on switched voltage and current because switching a high voltage or current ...

### Can't Read current on Pololu Dual MC33926 Motor Driver Shield for Arduino

I know this thread is old but it's high on Google results and I would like to clarify for anyone who stumbles upon it in the future an answer not yet listed: this chip is not designed to read current ...
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### How to test how much current 9 servos can draw at a time?

I assume that all the servos are identical, so it is enough to measure only one, and multiply the result by 9. The best would be if you could use a lab bench variable power supply, like this. With one ...

### Servo motor power consumption issue

Firstly consider the servo torque limitations, if loading increase from specified limit the it start stalling and even can gear get fail and burn servo itself, possibly. And another concern is with ...
1 vote

### How dangerous are HASEL artificial muscles with its Kv requirements?

So first, always take precautions when dealing with electricity. Discharging capacitors, removing metal jewelry, safety glasses, insulated tools, etc. If it's a commercially available product then I ...
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1 vote

### How to deal with current spikes due to fast direction-switching motor commands?

You can try to put a capacitor in the motor terminal. Very close to the motor.
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### How to pick the right motor driver?

For every component you can search for data sheets over the respective manufacturer site. You can know the rated current of motor otherwise on the shopping site. Then find a motor driver for that ...
• 11
1 vote

### How can a motor be run at higher voltage for longer?

Running a motor with a higher voltage might reduces its lifetime. However there are some cases where we want to run motors above the rated voltage. According to the equation V = IR, current increases ...
1 vote

### How to deal with current spikes due to fast direction-switching motor commands?

It's maybe not this at all, but when a motor or any inductive system suddenly stop it create a short opposite surtense that can affect your microcontroleur. The solution is to ad a flyback diode ...
• 11
1 vote

### Servo motor power consumption issue

From the TowerPro website from the MG995: Specification: Weight: 55 g Dimension: 40.7×19.7×42.9 mm Stall torque: 9.4 kg/cm (4.8v); 11 kg/cm (6 V) Operating speed: 0.20 sec/60° (4.8 V)...
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### Brushless DC motor problems at high velocities

Nice detail in your question. The somanet site makes a big deal about their firmware being open source, so you should be able to check the timing in the code (or otherwise get the help of the somanet ...
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1 vote
Accepted

### what is the difference between a voltage source and current source?

You are correct in that they are related, via Ohm's law: $$V = IR \\$$ The difference is in what gets regulated. A voltage source will keep supply voltage at a constant level by altering the ...
• 14.5k
1 vote

### What are some ways to estimate torque/load on a robotic arm joint

50k4 did a good job of enumerating the different ways to measure torque in the joints. So I won't go into that. But if you want to detect unexpected impacts, another option is to use accelerometers. ...
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### Can too much input current destroy my motor driver?

If I might add to the previous answers: I noticed in the referenced datasheet that the 20A maximum current rating for this driver is limited to less than 10 seconds and the maximum current is further ...
• 11
1 vote
Accepted

### How can I reduce a motor's maximum current draw?

First of all the link you posted states that your motor driver carrier board has built-in overcurrent protection...so...where is the problem? If it does not have: Put a fuse in series with the ...
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### How can I reduce a motor's maximum current draw?

Heat is an important problem with a series resistor used to limit stall current. Wattage of I amperes through R Ω is I²R, so 7.35 watts of heat are produced at the motor's nominal 7 A operating ...
1 vote

### Comparison of the efficiency of DC motor current limiting / control methods?

Of the choices you presented, PWM + BJT/FET is most efficient. An H-Bridge is a prime example of that. -BJT's dissipate heat in proportion to their "on-ness" -FET's dissipate heat based on their (...
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1 vote
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### Arduino with two Linear Actuators, two ACS714 Current Sensors, and an L298N Motor Driver setup

Yes, that looks like it will work. Keep in mind that the arduino io pins aren't powering any logic. Most Arduinos can provide more than 500 mA from their 5v pin assuming that they are connected to a ...
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