Brake Problem

There's something contradictory with your statement.

You say that the brake releases when voltage is applied. When voltage is off, brakes applies. But you also say that when the DC motor is running, the brakes suddenly engages by itself and you get smoke, heat and tension loss (I don't know what you mean by tension loss but that's okay). You checked and no voltage drop is found?

That should be your answer right there! If there's no voltage across the brake, the brake is engaged and your motor is still running, resulting in smoke, heat and that thing.

How is the voltage to the brake applied? Some brakes take their voltage from the motor wires. When the motor is powered, the brakes have voltage and it releases. When you remove the power, the voltage drops to zero and the brake engages. Some applications have a separate power source for the brakes. Whichever one you have, your brake is losing it's voltage and that's what you need to search for.

Contradictory???

What I meant by "no voltage drop" is voltage still exist and it's 23VDC (brake voltage should be 24VDC, tolerance -10% to +6%). "No voltage drop" doesn't meant no voltage, but there's still voltage and no drop in its rms-magnitude. The word "no" emphasis on the word "drop" not on the word "voltage".

So brake should be kept in releasing, but sometime brake engage by it-self while there's no voltage drop after I checked. This mean ; voltage is still exist in both DC motor and Brake it-self. Please, tell me why? This brake is fail-safe mode.

Tension Loss ? this is the consequence of brake problem in one package of machine. DC motor is used to draw a load, when brake engage while DC motor still rotating, thus Brake will try to stop motor, motor become slow motion then tension will be lost. Then by serial link, all other unit machine must trip for safety reason. This is OK.

Please, do not discuss about relationship between torque and tension, it's out of my problem.

Hoping giving you a light, give me a light, too.

THanks, Vulkan, keep in touch with me.

Okay, sorry about that but there was a difference in terminology between us. When we say, "no voltage drop", it's the same as saying, "there's no voltage". What you're actually saying is that the voltage did not drop.

So the problem becomes clear (though the solution may not be at this time ).

I believe what you have is an intermittent opening in your coil winding in the brake. Your brake is actually a solenoid. When the coil is energized (voltage is applied), the brake pad or disc is pulled towards the coil and away from the motor's brake plate (can't think of the proper term at the moment).

Since the voltage is still present but the solenoid is not energized (brake is engaged), your coil is probably opening intermittently. Simple solution is to replace the brake coil or the entire brake mechanism as they usually come as a set.

What you could do is to measure the electrical resistance of your brake. If it's reading as open, there's your culprit. That might take some luck since it is intermittent. Sometimes, you'll get resistance, sometimes you won't.

Good luck.

The brake may have it's voltage and lost it's ground.or the solenoid that releases the brake is defective.

or the solenoid that releases the brake is defective.

That's what I said in post #3. The coil (or solenoid coil) is open (or defective). We're using different words for the same thing.

Not knowing the particulars of the unit you have, many brake units require a calibration of some sort. This calibration normally sets the minimum gap between plates so that the proper movement of the brake disc happens as it should under application of power.

I have seen it happen where new, or rebuilt, units are put into service, without the calibration having been done, that cause problems when they heat up. The problem can be attributed to "drag" between the rotating and stationary plates plates that are not sufficiently separated from each other.

FWIW, I would contact the manufacturer, or check the manuals (you have done that already right?), for a calibration procedure, perform the procedure and see what happens.

Assuming solenoid is working properly, its most likely your pads are binding when subjected to the rotating disk (assuming disk) and not fully releasing. And, maybe also, your pads are not properly sized to absorb the breaking energy - too small to stop the train.

Why don't you contact Stromag directly? http://www.stromaginc.com/

It would be the intelligent thing to do whenever you are seeking answers to a problem with a piece of machinery!

After all who would know more about it than the people that make it?

DUH!