If I Need to Lower the Rotation Speed of a DC Motor, but Can't Change the Voltage What Is the Eaises

You are on the right track with a potentiometer. First, the pot must be capable of handling the amount of current you are passing. Higher wattage pots are usually wire wound and can be quite large when amperage is high. If you wired the pot in parallel with the motor, you are simply using more current and will not slow the motor. Wire the pot in series with the motor to lower the voltage to the motor. Part of the voltage will be dropped across the pot. To select the proper value potentiometer, look at the motor and see if it has an amp or wattage rating on it. Otherwise, you may have to use an amp meter in series with the motor to see how much power (watts) is being used for proper sizing

1. How to perform System Identification on DC motor?

You could do this with a pencil and a paper. I am not going to go into all the steps because it would devalue your learning. First draw your control system and label each 'thing' in your system (controllers, motors, ADC's, encoders, ect) and also figure out what the relationship of the control signal and relationship of the physical units (voltage, current, RPM and digtial signals if you have them) of your system between them. Once you have an idea of how you would drive you system and what it looks like.Then record some data to build a model for the motor (and drivers) First do this open loop, vary the input out of the controller and record the values going into the controller. Put a step input into the 'Plant' and figure out what the open loop response is. Find the steady state response. Does it have overshoot? (hint the step response has a frequency response in the laplace domain and FFT's are a great way to get stuff into the frequency world) Figure out what kind of 'plant' you have from this data(its probably only going to have 1 or 2 poles and zeros) by using the steady state response.You could also input a known frequency and then sweep the frequency higher and higher and then observe the output. This can be useful for finding frequency cutoffs. Once you have figured out a model for your plant, from the open loop case you can start designing a controller. Do you have a digital or analog controller. If it's digital you will probably want to transfer the open loop plant to the z-domain and do your analysis there. Another option is to run a digital PID controller on your Arudino and tune it.

2. Driving a large, noisy, free-wheeling DC motor (cooling fan)

NOTE : I am not attempting to answer the whole question.The startup spike is not an inductive spike : that will come when you switch it off. The startup spike is purely resistive : the 12V source divided by the motor's DC resistance. Measure that accurately (several times, rotating the fan between each, and picking the lowest) and you can calculate the stall current, which will also be drawn momentarily, until the fan starts spinning, so the motor can build up back-EMF.If the normal operating current is 15A, the stall current could be in the region of 100A. Knowing the actual current will help you pick suitable MOSFETs or solid state relays for whichever solution you choose.

3. How do i find out what how much electricity a DC motor can generate?

Spin it, and measure the output across the terminals. That would be an open circuit measurement, which could be very misleading because of no current draw from the device. What you need is to know the resistance the computer poses to a battery. That can be derived from taking the operating voltage, usually 5 volts and dividing it by the current listed on the tag that is on the computer that gives voltage and current requirements. Once you have that information, put that size resistor across the motor being spun as a generator, and see how the device holds up under that load. Your number one problem in all of this is that I am certain that short of an at home experiment, your project is going to be a flop in actual use. Either go and buy a new battery for the computer, or get an inverter power supply that plugs into a wall outlet for your computer. Energy does not come free, and your idea just is not going to perform as you want it to. Physics, and engineering are against you

get in touch with us
추천 기사
Shunt DC Motor Controller Improvement
Shunt DC motor controller improvementSo this looks as if the circuit controls armature current?It controls armature voltage.would it be better if the winding current was controlled?Controlling armature current with an outer voltage or speed control loop would be better, but more complex.By "winding current" I suspect you mean field winding current as apposed to armature winding current. Controlling the field winding current would make the minimum operating speed about equivalent to the present maximum speed. Reducing the field current will increase the speed and reduce the torque capability. I doubt very much that is what you want.The above seem to be the only actual questions asked. The question seems to imply that you wish to improve the control scheme because the motor " runs slightly erratically." You have not actually described what aspect of motor performance is undesirable.Speed decrease with increased load is normal for a simple armature voltage control. Random speed variation with a steady load could be due to line voltage variation, other power quality issues, motor brush problems or a loose connection. Failure to start relably would like be a brush problem— — — — — —Can you use an AC switch with a DC motor?Just follow the ratings of the switch. Typically, the DC voltage rating is less than the AC voltage rating. Current ratings are normally the same— — — — — —What is an interpole in a DC motor?Thanks for A2A.Purpose of Interpole in DC MachineFor understanding the role of Interpoles, we need to understand the effect of armature reaction in the DC Machine. The effect of armature mmf on the main field flux is to distort the main field flux and to reduce the net main field flux. The figure below, shows the effect of armature mmf on the main field flux. It is quite clear from the above figure that the flux at the location of Carbon Brush i.e. A, B and A are not zero and therefore an EMF will be induced in the coils undergoing commutation and will lead to the sparking. As we know that for better commutation, the coils short circuited by the brushes should have zero EMF induced in them. As the zero crossing of field flux is shifted due to armature reaction, the coils undergoing the commutation will have a net EMF induced in them. This induced EMF in the short circuited coil will delay the reversal of current in the short circuited coils and will result into poor commutation and sparking at the carbon brushes.The question arises how to resolve this issue?If we see the figure above, we observe that there is a net shift of zero crossing of net flux in the air gap by an angle Ɵ in the direction of rotation for Generator and opposite to the direction of rotation for Motor. So the cheap and easy solution shall be to shift the Carbon Brush at Zero Crossing of the air gap flux.Thus carbon Brush need to be shifted by an angle Ɵ from Geometrical Neutral Axis (GNA) in the direction of rotation for Generator and opposite to the direction of rotation for Motor.But this method of shifting the Carbon brush has a big disadvantage. What is that?As the Armature Reaction depends on the current flowing through the armature winding which in turn depends on the load current. Therefore as the loading of the DC Machine varies the angle Ɵ will also vary and therefore we need to continuously shift the Carbon Brushes. So we need to find a smart way.Again, looking back to the figure, if it could be possible to make the resultant or net air gap flux zero at GNA, then there would not have been any detrimental effect of armature reaction on commutation. Also, the existing flux at the GNA (at point C) is due to North Pole so we could use a South Pole (opposite of the pole which produced the imbalance at C) at C so that the net flux at C becomes Zero. Similarly at C' we can use a North Pole to make net flux Zero there. Okay, this will work fine but how t change the magnitude field strength of this newly installed poles at C and C'? Hmmmm. .We can use a winding on the newly installed poles at C and C' and connect that winding in series with armature winding so that the strength of field due to newly installed poles at C and C' varies proportionally will the loading of machine. Yes, this will work fine.So we can conclude our solution as,We will use Poles same as that of Main Poles ahead of GNA or Carbon Brush for Generator at the location of GNA or Carbon Brush and Poles same as Main Pole that of behind the GNA or carbon Brush for Motor at the location of GNA or Carbon Brush and will use winding on them and connect them in series with the armature winding as shown in figure below.The Poles used in our smart solution is called the Interpole. Interpoles are narrow poles placed at the GNA and fitted to the Yoke and also known as Commutating Poles or Compoles. For generator, the polarity of Interpoles must be same as that of main Pole ahead of it in the direction of rotation. For Motor, the polarity of Interpole must be same as that of Main Pole behind it. So I expect that you understand the purpose of Interpoles as you only designed it. But there is one more interesting role of Interpole.Interpole do not only nullify the effect of armature reaction but in addition, produces some extra mmf in the interpolar zone. This extra mmf in the interpolar zone induces rotational EMF in the short circuited coil undergoing commutation in such a direction to oppose the reactance voltage in the coil. Thus the resultant the resultant voltage in the short circuited coil becomes zero and the commutation is spark less.What is an interpole in a DC motor?
How Can I Calculate DC Motor Continuous Current?
How to Use Raspberry Pie to Control DC Motor
Zero Crossing Events with Brushless DC Motors
Cause Analysis and Solution of Permanent Magnet DC Motor Noise
What Is the Definition of Kv Value of Brushless DC Motor? Is the Kv Value the Greater the Better?
PWM Speed Control of High Power Brushless DC Motor Based on 51 Single Chip Microcomputer
Application of Permanent Magnet Materials in Permanent Magnet Brushless DC Motor
What Are the Methods to Change the Speed of Micro DC Motor?
what is the best time of year for dc motor sales?:2021 best dc motor
related searches
How to Use Raspberry Pie to Control DC Motor
what is the best time of year for dc motor sales?:2021 best dc motor
Maximum Value of Back Emf in Dc Motor?
Strongest DC Motor I Can Find in the 500-750 Gram Range?
PWM Controlled MOSFET Based DC Motor Driver, Stuck with Reverseing Direction
Voltage Divider in Parallel with DC Motor Driven by H-Bridge: Can Someone Explain Me This Circuit?
How to Decide the Rating of DC Motor for a Given Torque?
Change Direction of 12v DC Motor Rotation Using Relay
Effect, If Any, of Input Voltage on RPM of DC Motor

Copyright © 2020  Shandong Abusair Agricultural Machinery Co,. Ltd- |  Sitemap

Multifunctional farm Abusair machinery  |  Tea Professional Cultivator farm machinery