Indramat 3trm2

I'm preparing the diagrams and will post them soon, but i noticed something, i removed mesa from the loop and signaled the indramat via a battery. X and z axis move only when i connect the battery. But when i turn y axis in clockwise it works fine but when i turn it anticlockwise, it drifts, it doesn't stop quickly as it should. This might be the problem. Any suggestions?

Yeah, so in clockwise direction, i feel the resistance but in anticlockwise direction it rotates easily. As i stated above, when i run indramat with battery, it drifts in anticlockwise direction but runs ok in clockwise direction.

This doesn't sound right.

On our Maho, we couldn't get the following error acceptable by tuning ff1. It wasn't "centred" around 0, so you could tune ff1 to get it 0 in one direction, then it would be out in the other.

The problem was the tacho. The stator of the tacho on the motor can be rotated. If it is not in the correct position, the tacho feedback voltage is not the same in both directions for a given RPM of the motor. It should be the same, but negative at the same rpm but different directions.

I think you may have another problem on your drive though.

I think this is a half wave thyristor drive. I haven't done it before but it might be useful to check thyristor gate pulses using an oscilloscope.

It is strange though that the drive doesn't report an error....is the drive ready relay (BB I think) contacts closed?

Bb1 and bb2 were connected with a short wire when i received the maho. So i didn't bother changing them. But the wire connector on the motor is tilted a bit(on the other motors, it is at 90° with respect to the motor flange). How can i determine that the tachometer wound stator is in correct position with respect to the stator magnets and brushes?

I think you need to open the back end cover on the motor to get to the tacho.
Compare the position with one of the other motors that is working.

I turned the tacho similar to other motors, now the motor doesn't have any torque when turned on, any ideas? All the carbon brushes look fine to me.

Does the drive take encoder signals for position and velocity feedback, and then relay this back to the Mesa board? Can you check that the encoder is working properly? There may be a defect in that Indramat drive that is causing it to not register the encoder properly.

Jon

There is only a tacho on those motors. No encoder. Position feedback to lcnc is from the linear scales on each axis.

Can you verify that the tacho is working when you spin the motor shaft by hand? You should see at least 1 to 2 volt.

I expect the motor to run away if the tacho is not working so I expect that there is something wrong with the drive.

OK, more old-school than I thought. Well, there has to be an issue witht the tach or the circuit that receives the tach signal and feeds it to the velocity error amp. Since rotating the tach body changed things, then I'd definitely try turning it the other way.

Jon

hello,

you can change the motor and tacho wires on the drive between x and y axis.
if after this, the same behaviour is on the other motor, you know that the fault is in the drive.

If your y-axis on the maho is still the vertical one, then a little assymetric behaviour is normal. this depends on the calibration of the thyristor firing circuit, because the table everytime wants to move down...
if the motor constantly turns changing left/right direction, you also have to calibrate the firing circuit (pictures with the saw-tooth in the manual)
Do you have the service / calibration manual?