Very good demonstration, thank you. Altho I think the braking effect could be easier to see with a small flywheel connected to the motor. Could i increase the braking effect further by feeding dc current through all three windings, instead of just one? And how much current can i feed through the windings without the motor taking any damage? All the way up to the motors rated ac current? Thanks.
is there a way of braking a motor without spending electricity but instead generating it? I know, regenerating brakes, but how does one keep a constant rpm?
Is this what is used in a drill. I just want to know how the mechanism works that stops the drill on a dime. Very interesting to me. Also i know the polarity is reversed but how does that work? Reversed for a split second? Or what?
How much heating effect do you get with a system like this? I'm reading about various forms of motor breaking and I am getting different impressions depending on who is talking. Some say DC injection will overheat and burn your motor easily and you need special cooling to avoid it, others say it's fine and not that much of a problem. I'm considering options to brake a bandsaw with a 5kw 3ph motor and cast iron wheels that act as flywheels.
I would think that if you are doing it intermittently, and braking a light load with little momentum, it would be ok. You can also use rheostatic dynamic braking - just disconnect the motor from the power, and then connect the motor terminals to a resistor. The spinning of the motor generates current. When the current is directed through a resistor, it slows the motor. Trains use this method. However, big trains have a lot of momentum, so the dynamic brakes work by using current generated from the drive motors, and passing it trough massive resistors beneath forced air flow to keep them cool. Another important fact to keep in mind with this type of dynamic braking is that as the speed decreases, so does the braking effect. Example - A train going at 100mph activates dynamic braking. In the first ten seconds, the train slows to 90mph. over the next 10 seconds, it might slow to 82mph, the next 10 seconds, 76mph, 70mph, 68mph etc. When the train is moving slowly, the current generated in the traction motors is very little, so braking force would virtually be nil. It's very clever how it works!
If there is 45Kw vfd and 11 kw 4 nos of motor of connected in parallel with this vfd how much we will put dc current value in vfd and for how long time it may be injected for braking
@jxxh8su First, connect a lab-type DC power supply to your motor and experiment with the amount of applied voltage (and current) necessary to generate your desired braking torque. You can measure the torque using a pull string and a scale if needed. Then, select appropriate components to design an AC/DC power supply generating that amount of DC voltage and current. A simple transformer plus bridge rectifier power supply should work fine. No need for filtering, since the motor won't care.
Really great demo to visualize dc braking of 3 phase motor.
Awesome demo. very simple to understand this way. Thanks!
Nice demonstration, thank you.
great demo!
thank you guys for posting this..
it helps a lot..
Nice demo
Great video thanks
Wow! Awesome video,I wonder what types and what are they use for?
How do you determine the torque produced from the dc injection braking?
Very good demonstration, thank you. Altho I think the braking effect could be easier to see with a small flywheel connected to the motor.
Could i increase the braking effect further by feeding dc current through all three windings, instead of just one? And how much current can i feed through the windings without the motor taking any damage? All the way up to the motors rated ac current?
Thanks.
is there a way of braking a motor without spending electricity but instead generating it? I know, regenerating brakes, but how does one keep a constant rpm?
Does this mean that eventually electric cars may not need breaks? Especially if they are 4 wheel drive?
Is this what is used in a drill. I just want to know how the mechanism works that stops the drill on a dime. Very interesting to me. Also i know the polarity is reversed but how does that work? Reversed for a split second? Or what?
Is that the break will be applied for both the direction of rotation (pls upload by rotating the shaft in both direction of rotation)
So if you lose brake power, the brakes don't work. I thought power loss was generally supposed to result in the motor to stop and the brakes to shut.
How much heating effect do you get with a system like this? I'm reading about various forms of motor breaking and I am getting different impressions depending on who is talking. Some say DC injection will overheat and burn your motor easily and you need special cooling to avoid it, others say it's fine and not that much of a problem. I'm considering options to brake a bandsaw with a 5kw 3ph motor and cast iron wheels that act as flywheels.
I would think that if you are doing it intermittently, and braking a light load with little momentum, it would be ok.
You can also use rheostatic dynamic braking - just disconnect the motor from the power, and then connect the motor terminals to a resistor.
The spinning of the motor generates current. When the current is directed through a resistor, it slows the motor. Trains use this method.
However, big trains have a lot of momentum, so the dynamic brakes work by using current generated from the drive motors, and passing it trough massive resistors beneath forced air flow to keep them cool.
Another important fact to keep in mind with this type of dynamic braking is that as the speed decreases, so does the braking effect.
Example - A train going at 100mph activates dynamic braking. In the first ten seconds, the train slows to 90mph.
over the next 10 seconds, it might slow to 82mph, the next 10 seconds, 76mph, 70mph, 68mph etc.
When the train is moving slowly, the current generated in the traction motors is very little, so braking force would virtually be nil.
It's very clever how it works!
If there is 45Kw vfd and 11 kw 4 nos of motor of connected in parallel with this vfd how much we will put dc current value in vfd and for how long time it may be injected for braking
Nice and easy
most of things are not difficult indeed but not demonstrated good enough
How to do this for 2kw bldc motor?
Is brake important for motor?
Hi When an engine is breaking with this technic it's impossible for it to "regenerate" any energy?
Exactly
will the motor be heating or have any damage? What the limit of DC voltage we should apply? can someone help me solve this question?
@jxxh8su First, connect a lab-type DC power supply to your motor and experiment with the amount of applied voltage (and current) necessary to generate your desired braking torque. You can measure the torque using a pull string and a scale if needed. Then, select appropriate components to design an AC/DC power supply generating that amount of DC voltage and current. A simple transformer plus bridge rectifier power supply should work fine. No need for filtering, since the motor won't care.
is it possible to dc inject a bldc motor to brake it?
Try to connect to resistive load, please.
motor price