Good day. I need advice. I have a BTS7960 bridge and I would like to brake a 350W 20A motor with it. The engine is loaded with a 20KG basket, at 100 rpm. The engine should stop the basket within a maximum of 20 s. The BTS7960 bridge can handle it. Didn't they sleep upstream? Which generates the dc motor. I want to brake by reversing.
The braking force is good when the motor is spinning at speed but decreases to zero when the motor is at zero speed.
The same technic was used on trams and they used a mechanical brake for the very last part of the stopping.
Go ahead and do it.
What is the shape size of the basket and distribution of mass?
What is the torque of the motor - including any gearing that exists?
The shape of the basket is crosswise. The weight of the basket is 2Okg. The torque of the motor is 175O rpm for at least 350W. Basket speed max 100 speeds per min
correction: not 100 rpm, but 50 rpm
I don't want a mechanical brake. I'm not reworking the car. But a reversible honeycomb. I'm a beekeeper. I need it the easiest
It doesn't matter what You want or not. Zero speed will never be reached. Learn the theory for induction and magnetic fields, due to movements. It's fundamental.
correction: not 100 rpm, but 50 rpm
Applying like reverse polarity is needed to keep the motor at a stand still. That costs energy all the time to keep the motor at a stand still. Upon a main power fail the motor will move the weight down.
I know that. I am both an electrician and a beekeeper. I just don't know which method of braking is the most effective.
so 14. 8. 2021 o 22:32 Railroader via Arduino Forum <firstname.lastname@example.org> napísal(a):
Fine. Sorry I entered the matter at a too low level.
Just regard the power fail consequencies. I experienced what a powerless stepper holding some 100 kilos on a ball screw did when the emergency button was presded.. Big bang...
I have programmed an ARDUINO Deu with a 7 inch display- only the brake makes us a problem. because. the dc motor is switched as a generator when reversed and produces current. recovers voltage to the network. Probably no one has experience with braking dc motors. I'll do a relay and a power resistor. To convert the voltage into heat. My name is Marian I am from Slovakia
"crosswise" isn't a shape or a size - I'm asking for the details of the load - a picture might be easiest.
Can't see any torque or gearing details...
I don't know the BTS7960 bridge and what i handles. I would need to dig down in that.
Applying a load to the motor, when it is running, will of course make it brake. That's how they did on the old trams. Monitoring the RPM of the motor looks obvious to me, to find the point when the proper action can be applied, reverse polarity, resistive load can step in.
Just letting the driver go from speed to zero makes the motor act like braking. Diodes in the bridge goes to work.
Time is late here. See You tomorrow.
How do you know when to start the braking process?
How are you giving signals to the BTS7960? Are you using PWM to control the speed of the motor?
I use a due timer. Start time - speed time - brake time. YES -PWM. Accordingly, we work a speed regulator. I haven't solved the brake yet - smooth braking. I will probably have to design a pcb for my needs with PWM control. The BTS7960 controller will not be able to overload it.
ne 15. 8. 2021 o 0:05 cattledog via Arduino Forum <email@example.com> napísal(a):
I use a due timer. Start time - speed time - brake time. YES -PWM. Accordingly, we work a speed regulator. I haven't solved the brake yet - smooth braking.
If you are controlling the movement by time, then at some point in time you need to start reducing the pwm duty cycle in steps to slow the motor down to the point where it stops. This is no different from dimming an led over time. There are plenty of examples.
You can reverse the voltage if you need to.
I saw one connection. Bridge disconnection H BST7960. And using a relay, a power transistor series of amps + a power resistor + a diode, brake the motor. it is braking through a resistor.
It's not an ice dimmer! Because, there is the inertia of the rotating basket + motor. So I have to brake the motor.