# motor drive control conical-rotor brake motors --help



## sparkie

We have a machine fitted with two Demag motors in parallel.

when the motor is fluxed, spring loaded rotor moves and releases the brake

* The supplier who chose this unit*
(leading manufacturer in this country)said that this type of setup has worked previously on another make drive control. 

The problem we have is the motors are not becoming fully fluxed 

Speed mode it doesn't move.

Torque mode-it's like driving down the road with brake on and we are not prepared to wind torque current up too high in case of motor failure.

so far we have entered the motor rating plate data as instructed by manufacturer and inserted the combined current rating.

Performed the self test and allowed it to compute the setup.

Both speed and torque modes do not produce required flux to pull off the brake- can anyone point us in the right direction of any data relating to two motors and if it affects COS value or similar setup

Or for that matter anyone had a similar issue and resolved it

We thought that setting it up like a lift motor would work, but so far no joy.


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## frank

I do not know what type of motors you have - but if they have any DC braking component check that there is no DC being applied prematurely to the stators. Just a guess . Would be better to see the full set up. Also. In the deep and distant past i seem to have come across a similar problem with a single motor application. In this case the motor would not flux because it had not been exited correctly.

Frank


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## sparkie

hi frank these are strange motors, the rotor is sprung loaded and when the windings power up it causes the shaft to move (like a solenoid) and this causes the brake drum to lift off shoe.
There is no dc braking and according to demag these motors can have drive speed control

http://www.demagcranes.com/Products...ke_motors/Product_details/index.jsp?prospekte


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## sparkie

Sorted it, :thumbsup:
Software bug-the panel and inverter operate as two modules that can upload to each other, several power cycles and factory resets.

we found

Fast run do not use DC setting
Decided to do a short id run, motors do not move, but you can see a solenoid action occurring as motor windings flux and apparent clicking.

We are using digital inputs run right, run left, enable,stop and reset.

We were able to run the motor in one direction reliably, for some reason occasionally we experienced what appeared to be dc locking up the motor in speed mode.
Changing to v/hz mode and auto IR comp- we had reliable two way drive control.


Regards Daniel


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## frank

Hi Daniel

Glad you got it sorted. Just a note for the future in case you think such things can't happen - but - control of such motors carry an inherent poor fluxing factor. So poor speeds can sometimes be expected and not easily overcome. There are Companies out there that offer a better fluxing/speed control systems than others so the first install option may not in all circumstances do the trick. It's a tricky business but good fun.

Frank


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## sparkie

Yes have experienced this, basically your at the mercy of the makers algorithm and software.

Also open loop systems without encoders etc are a joy sometimes.

this is on a gantry crane used in steel production, we had to synchronize it to another, so two cranes can move large steel beams.

As you can imagine a production machine they don't like down time. 
Friday 13 :thumbsup: superb


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## Simisteven

sparkie said:


> Sorted it, 👍
> Software bug-the panel and inverter operate as two modules that can upload to each other, several power cycles and factory resets.
> 
> we found
> 
> Fast run do not use DC setting
> Decided to do a short id run, motors do not move, but you can see a solenoid action occurring as motor windings flux and apparent clicking.
> 
> We are using digital inputs run right, run left, enable,stop and reset.
> 
> We were able to run the motor in one direction reliably, for some reason occasionally we experienced what appeared to be dc locking up the motor in speed mode.
> Changing to v/hz mode and auto IR comp- we had reliable two way drive control.
> 
> 
> Regards Daniel


Hi Daniel are you still around?
If so I havea question for you regarding this Demag conical brake motor


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## joe-nwt

Report
*sparkie*
Registered · From UK South West
Joined Apr 2, 2008
Last seen Dec 20, 2016


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