Drive problems .... Arghhhhhhh

[Cowmanator]

when changing direction the brake was never coming in to play

 

[milad.rahmani67@yaho]

hi every body
i have a problem in acs800 and i have 2 questions if anyone can help
the problem is: the "comm module" fault (FW 02.12) occurs usually and it has not been reset by the reset button on the panel.(but the drive is working and it is not tripped). it can only be reset by turning the DC voltage on and off !! what's the problem?
now i want to write an additional block in DriveAP and use
BSET block to make it reset by reset button on the panel.
1- do you think it will help or not?
2-the reset button on the panel is included in which parameter? i mean when i push the reset button on the panel, which parameter and which bit is changed?

 

[Steve Bailey]

I suggest you start a new thread. This one was related to a different problem.

 

[jraef]

I still think the issue is related to your having used open loop Sensorless Vector Control, and the drive not being able to ensure there was enough shaft torque. So the drive was putting out torque, just not enough to keep the load from falling. But that only became evident when that rapid direction change took place. By adding the encoder feedback, the drive now knows what's happening in the motor.

One issue I see happen to people is that they witness an SVC drive working on a hoist, and assume they all work on all hoists, which is the dangerous assumption. They work when there is a mechanical issue that will not allow the load to drop anyway, such as a right angle worm gear driven hoist, or a conical motor like on a Demag hoist that will not let go of the rotor until AFTER the motor has already developed sufficient torque to hold the load.

 

[GaryS]

change the drive to a Electromotive hoist drive and you problems will be solved
standard VFD's are not designed for use as a hoist drive.

 

[jraef]

change the drive to a Electromotive hoist drive and you problems will be solved
standard VFD's are not designed for use as a hoist drive.

That was probably true 15 years ago, but not any more. Much of the rest of the drives world has figured out how to do torque proving now, although it's often something only implemented in the high-end products. A-B does in on theirs, all the way into Medium Voltage. And as DickDV said, ABB offers it in their high-end drives as well. I can think of a half dozen others off the top of my head.

The thing that was special about Electromotive back in the day was that they had their own custom chip added to the old Yaskawa P5 drives back when nobody else was doing this with AC yet. That same Yaskawa drive was marketed through Magnetek, Saftronics, IDM and EMS at the same time, but only Electromotive had that chip which added the Torque Proving algorithm that was necessary to ensure the drive could hold the load still when the brake was released. That's no longer true. Yaskawa bought out Magnetek and EMS, then fired Saftronics, but Magnetek then bought Electromotive so that's the only Yaskawa drive they sell now because of it being a specialty package for cranes and hoists. However you can now get the same features in several other product lines that Yaskawa sells too. It's just not that special any more.