VFD Compatibility

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Jraef said:
The perception that it is Wye Delta but that it worked with two speeds and is an IEC motor likely means it is what they call a "Dahlander" motor, what we call a "2S1W" for 2speed 1winding. To the untrained eye, it appears similar to a Wye Delta starting scheme, but it is different in that it changes the number of motor poles, not just the connection pattern. If that was the case, the original control system would have had to introduce a delay when changing speeds because there was a phase shift between the Delta and Y-Y connections that made the two speeds happen. If all you did was remove the contactors, replace them with the drive and used the speed relays that turned on the different contactors to provide preset speed inputs to the VFD, you may have inadvertently left behind the pole changing delay in the relay logic and introduced it into the VFD's run command signal.
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The motors have two windings, low and high, landing on different contactors. I am familiar with the "2S1W"; just don't see it often.
The drives are getting worse, starting over today, and looking at contact point at buss system. A new week, a clean slate; sure seems this could've been more straight forward than I have made it.
 
Jraef said:
The perception that it is Wye Delta but that it worked with two speeds and is an IEC motor likely means it is what they call a "Dahlander" motor, what we call a "2S1W" for 2speed 1winding. To the untrained eye, it appears similar to a Wye Delta starting scheme, but it is different in that it changes the number of motor poles, not just the connection pattern. If that was the case, the original control system would have had to introduce a delay when changing speeds because there was a phase shift between the Delta and Y-Y connections that made the two speeds happen. If all you did was remove the contactors, replace them with the drive and used the speed relays that turned on the different contactors to provide preset speed inputs to the VFD, you may have inadvertently left behind the pole changing delay in the relay logic and introduced it into the VFD's run command signal.
Click to expand...

I had a sneaking suspicion about the Dahlander drive. Furthermore, if it was used wit an SEW ASD befoe, I was wondering if the speed-change did not initialize a new set of parameters in the drive first. The two sets of windings WOULD make that necessary. I am not aware if you can do that with the AB drive. So either you go back to the original SEW drive with the exact parameters they had or buy another drive and have two AB drives, one for the low speed winding and one for the high speed winding. Isolating contactors and all that jazz...a POA.

The flying restart with a single is not working since your motor parameters are different for the two windings. At initialization, when the motor performs the characterization of the circuit only one set of windings are characterized and when you switch to the high speed winding, you will have what you're experiencing where the ASD is trying to control based on the original set, so it is 'adjusting' when you switch to high speed and even with that it is questionable if it can control it correctly from that point to the end of the speed curve.

You can try to use a single winding, I would choose the high speed, and reconfigure your controls around it. The question here will be if you can develop sufficient torque on the high speed winding for the low speed start. Instead of Hi/Lo speed pushbuttons just a 'dimmer' style potentiometer to go from zero to max speed. If you choose the two speed then eliminate all contactors and have the two speed controls directly wire into the ASD inputs and have the two speeds associated in the programing with the two inputs. Since this is a crane application and safeties are involved I wonder if the SEW had a 'safety stop' input.
 
weressl said:
I had a sneaking suspicion about the Dahlander drive. Furthermore, if it was used wit an SEW ASD befoe, I was wondering if the speed-change did not initialize a new set of parameters in the drive first. The two sets of windings WOULD make that necessary. I am not aware if you can do that with the AB drive. So either you go back to the original SEW drive with the exact parameters they had or buy another drive and have two AB drives, one for the low speed winding and one for the high speed winding. Isolating contactors and all that jazz...a POA.

The flying restart with a single is not working since your motor parameters are different for the two windings. At initialization, when the motor performs the characterization of the circuit only one set of windings are characterized and when you switch to the high speed winding, you will have what you're experiencing where the ASD is trying to control based on the original set, so it is 'adjusting' when you switch to high speed and even with that it is questionable if it can control it correctly from that point to the end of the speed curve.

You can try to use a single winding, I would choose the high speed, and reconfigure your controls around it. The question here will be if you can develop sufficient torque on the high speed winding for the low speed start. Instead of Hi/Lo speed pushbuttons just a 'dimmer' style potentiometer to go from zero to max speed. If you choose the two speed then eliminate all contactors and have the two speed controls directly wire into the ASD inputs and have the two speeds associated in the programing with the two inputs. Since this is a crane application and safeties are involved I wonder if the SEW had a 'safety stop' input.
Click to expand...


I like your observations. Other than the brake release contactor, all of the others have been taken out of play. We are using the high speed windings only, and I too question the torque when under load. I don't think SEW has anything in these cranes other than bridge motors. The cranes are around 15 years old and are the P&H/Morrissey brand.
Am making adjustments with the parameters. Hoping to have a better report tomorrow.
 
jimC. said:
I like your observations. Other than the brake release contactor, all of the others have been taken out of play. We are using the high speed windings only, and I too question the torque when under load. I don't think SEW has anything in these cranes other than bridge motors. The cranes are around 15 years old and are the P&H/Morrissey brand.
Am making adjustments with the parameters. Hoping to have a better report tomorrow.
Click to expand...
Again, the PF40 is not a vector control capable drive, open loop or otherwise. So if you are connected to the high speed windings and you are attempting to run it very slow, you are likely lower than the accuracy limitations inherent in Scalar (V/Hz) VFD technology. I would suggest a PF70 drive or if you have a decent A-B distributor available to you, the new PF525 drive. Both are capable of Sensorless Vector Control and will provide excellent performance at low speeds.
 
Jraef said:
Again, the PF40 is not a vector control capable drive, open loop or otherwise. So if you are connected to the high speed windings and you are attempting to run it very slow, you are likely lower than the accuracy limitations inherent in Scalar (V/Hz) VFD technology. I would suggest a PF70 drive or if you have a decent A-B distributor available to you, the new PF525 drive. Both are capable of Sensorless Vector Control and will provide excellent performance at low speeds.
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Or you can buy the ABB 550 at half the price or so:lol:
 
You guys may be right that the flex 4 is not the drive we need. In using 2 drives (src & snk), both are good a low speed, when we make the jump to high, we lose the src drive, and the snk cycles only to end up on the low setting. Not sure why we lose the src; conflict on inputs or if I have a parameter wrong.
Thanks for all of your input.
 
Jraef said:
Again, the PF40 is not a vector control capable drive, open loop or otherwise. So if you are connected to the high speed windings and you are attempting to run it very slow, you are likely lower than the accuracy limitations inherent in Scalar (V/Hz) VFD technology. I would suggest a PF70 drive or if you have a decent A-B distributor available to you, the new PF525 drive. Both are capable of Sensorless Vector Control and will provide excellent performance at low speeds.
Click to expand...

I'm sure you're right. I'm not sure any $'s will be spent to continue the experiment. I was told to figure it out with what is available.it just keeps coming back to torque. Whether or not the PF 4 IS capable of vector control is definitely above my pay grade; though I will be researching that here shortly.

I will continue with this experiment as long as they allow; maybe I'll get lucky and one of (two?) the recommended drives will be purchased.

Again, Thanks.
 
weressl said:
Same same for all of them. I used to have a problem with the Japanese drives with terribly written Jinglish translations. ABB is KING. Can you give an example what you presented a problem for you?
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I haven't programmed one in about 6 mos, so I don't recall all the details. I'll come back to this thread the next time I have to program one.
 
An update:
The AB 525 came in, installed it, and works pretty nice; with a couple of caveats.
Cannot go straight to high speed, it just crawls along at low; if you start in low and then jump to high works well and is smooth. Any ideas? I'm thinking I dont have one of the A group parameters set right; I guess it could be in the logic group though.
If travelling in forward and switch immediately to reverse, no change in direction.....not good. Any ideas, or is that just characteristic of an electronic drive? If so, no way they can be used for cranes (load sway control).
Thanks to all who are/have/will participate in this public education forum.
 
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