New answers tagged

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Yes, I felt that it kind of represented a PMM, but here's a bit more detail after reading the comments. The batteries would initially power the motor (wheels) until the PTO generator(s) get to their proper output and then the automatic transfer switch would switch over from the batteries to the generator. Now, that being said the battery bank would still ...


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The 'extra' wires will likely have functions specific to each individual motor and you'd have to check the corresponding data sheet. Some of the wires may provide for functionality such as a tachometer (how fast is it spinning), fault lines (e.g. 0 means the motor is stalled, 1 on this wire may mean the motor is functioning properly), some sort of serial ...


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Linear voltage regulators have a quality called "dropout voltage". It's the amount of voltage that develops between their input and output terminals at useful current outputs. The original 7805 has a dropout voltage of around 2 volts. It sounds like you're using one with a greater dropout voltage, or the BEC is dropping more voltage under load. ...


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For the hybrid or pure electric vehicle (EV) during regenerative braking the motor/generator already operates in generator mode to recharge the battery. The increase in fuel economy comes from the recovery of kinetic energy back into chemical potential energy during regenerative braking. How does regenerative braking work? https://www.youtube.com/watch?v=...


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The 298 is not a good choice for this. If you just want to switch the fan on or off, just use a low side MOSFET with generous Amperage rating. This circuit uses IRLB8721 which is nice because it's available in hobbyist places, it's through-hole if you're prototyping this on breadboard, and it has a low Vgs so you can drive it from typical microcontrollers, ...


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I don't understand what those power limits mean; will it damage the module if the load exceeds those limits? Source: L298N datasheet The datasheet lists three limits of \$I_o\$, it depends on how much time you have the output turned on. \$I_o\$ generates heat through the transistros in the H-bridge of the L298N, heat will damage the part. If the current \$...


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To answer the other half of the question, you could use a Schottky diode (with an appropriate current rating) as the flyback diode to reduce its temperature. The idea being that the lower potential difference across the Schottky diode will result in lower current x voltage heating. You could add a small-value resistor* in series with the diode to share the ...


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Other suggestions are correct but for immediate improvement find a “logic level” fet that can operate with 3.3V gate drive. They’re not the best but they exist. Change the 1k to <100 ohms and the 10K to 100K or remove it (the divider shown is slowing down the gate drive and dropping the gate drive voltage even further).


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You cannot use 1kR resistor on the gate!! I mean, you can, but then the MOSFET turns on and off slowly, therefore having non-zero power for a longer time in the cycle. And heats up... Use voltage of 5-10V and smaller resistor. Or lower frequency.


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The threshold Voltage of IRF3205 is between 2V-4V and the Raspberry Pi gives signal of 3.3v that will be fine No. Gate threshold is where the MOSFET barely starts conducting. So if it varies between 2-4V and you are applying 3.3V you are at best barely turning it on and at worst you aren't turning it on at all. You use at least the Vgs listed to get the ...


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You can supply sinusoidal voltages to a motor with trapezoidal back emf. The reason this is typically not done is because you will get torque ripple. Imagine you have a DC motor. \begin{equation} \tau=ki \end{equation} Now apply a rectified 3 phase sine wave current to the motor to get the average torque. \begin{equation} \tau_{avg}=\frac{3\sqrt{3}}{2\pi}ki_{...


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In reality, BLDC motors don't have truly trapezoidal back EMF. The inductance of the motor smooths the waveform out, resulting in the back EMF being much more sinusoidal. Trapezoidal, sinusoidal and FOC are all common and legitimate commutation strategies for off the shelf BLDC motors.


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not sure what stalled current means, exactly, but it's bugging me a bit Stall current is what the motor draws when you power it and 'lock' the shaft so it can't spin. Without spinning the motor can't generate a voltage to oppose the input voltage, so it will draw current according to its DC resistance. Most motors are not designed to do this for more than a ...


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Specs for motor 120/3 = 40 RPM/V 185/4.5=41.1 250/6 = 41.66 But you notice the difference on starting torque. 3V/1.1A = 2.73 ohms effectively. 4.5/1.2 = 3.75. 6.0/1.6 = 3.75 Your results will be equivalent to the voltage that is 1.5 V less than your battery because this is the nominal drop on the L293D’s. So you would need at least 4.5 but then you could ...


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Stall current is what the motors pull when they're not spinning. Unless you plan on starting them spinning by some external method, you'll be exceeding the L293D's maximum output current every time you start the motors--or if there's ever a load that they can't provide enough torque to overcome.


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Any DC motor controller should have current limiting built in. Preferably, the limit should be adjustable. A good adjustment range would be 50% to 150% of the motor's safe continuous current rating, depending on the motor design and intended use. Generally the current limiting function would be a closed loop active current regulator. The current regulator ...


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If the motor stalls whatever voltage goes into heating the coil of the electromagnet. This could be estimated if you have the coil resistance and the voltage going into the coil and the power equations. At the end of the day, it's the voltage (and for PWM the duty cycle) that determines how much power a load receives (because the load will limit it). Can I ...


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Also we didn't include any capacitors to smooth out the voltage rails The IRF520 MOSFET is rated to withstand voltage peaks of up to 100 volts and given that you took no care in ensuring the supply wouldn't glitch to this sort of level when loads are turned off (i.e. parasitic cable inductance in the feed to the motors from the battery), then there's a ...


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For cost reasons you don’t choose a high oz Cu board then etch away most of the Cu that you paid dearly for. You choose the wire gauge needed by the area and length for minimal Voltage drop and inductance by using jumpers, busbars similar with Litz wire for cables or twisted pairs. Next question?


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How do you dictate the copper oz pour/width that would meet a high amp requirement? It really depends on how much heating your design can tolerate and what temperature the designs "ambient" temperature will be. There are dozens of calculators (this being one of them) that can help you calculate the temperature rise. With at 40C rise and 40A that ...


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The answer is yes and no. If you connect the power supply with the motor's nominal voltage at standstill the motor would draw a stall current, this would happen also if the rotor is locked. It may draw this current for a very short period of time, like for startup. You can supply the motor with a fixed voltage power supply with an additional thermal circuit ...


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Is the stall current the highest amount of current the motor can draw at one time. For a brushed DC motor, the locked rotor current is the greatest amount of current the motor will draw, unless you are trying to reverse direction of rotation. If so would I need a motor driver that can supply a continuous current of at least 2.7 amps, to be on the safe side?...


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Well, you have an obligation to make sure that the final system does not experience driver failure when the motor is stalled. Motors can stall for a variety of reasons. But there is more than one way to achieve this. Keep in mind, also, that the motor will almost certainly fail if full stall current is allowed to continue for an extended period. You could ...


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The datasheet makes it clear that in any circumstance the PEAK current shall not be higher than 4.5A. The peak current is not a continuous current. It depends on PCB area size and number of copper layers, as well the thickness of copper layers It depends on environment temperature Therefore the device has been tested and it was found out that it can handle ...


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The "PWM" used in equipment for radio controlled models , is not actually true PWM where pulses are sent at a fixed frequency with an on-time proportional to the off-time betweeh 0% and 100%. The "PWM" used in RC is actually a a pulse that varies between 1-2ms in width. So for 0%-100% it would be 1-2ms. But if it's -100%-100% then it ...


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simulate this circuit – Schematic created using CircuitLab Basically it reduces the speed with regard to the torque. All drives have the same speed setpoint value and they reduce speed equaly if they are all loaded the same. When one of the drive is more loaded, it reduces the speed further and lets the other to accept the extra load. Kind of simple ...


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It’s my understanding that the inputs aren’t very high resistance, as FET inputs would be. With no load, they will pull up to 5 V with a very small current sourcing capability. If the microcontroller pins are set to be outputs, it’s highly likely that they won’t be pulled above 3.3 V. At reset though, the microcontroller pins will be inputs and may pull ...


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It means that if an input is not driven high or low by an MCU output, the pin has internal structure to pull the input weakly to VCC so it will be at high logic level. This will happen when the MCU is in reset and before IO pin is configured to an output. Or a bug in the code sets the pin accidentally as input. As the datasheet says, it is safe to connect ...


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A BLDC has a rotor with a permanent magnet. The induction motor (IM) has a squirrel cage and the rotor flux is due to induced current in the cage. In the IM most heat is produced in rotor, then transferred to the stator and through a shaft. When the IM is hot when you touch the outer stator casing, it means that the rotor is glowing red. A BLDC is a ...


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