VFDs with SEW Eurodrives

phuz

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Jun 2008
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I'm looking at a new project for a customer. We're taking an antiquated line and upgrading everything on it and adding AB controls. I want (and the customer wants) to use PowerFlex 525s; however, they already have some of the motors, which are the SEW Eurodrives. Is there any reason we wouldn't be able to bypass the built-in inverter control and run the VFDs directly to the 3-phase motor? The remaining motors will be sourced according to our upgrade plan.
 
I may be wrong, but I have never seen a SEW Eurodrive with an inverter as part of the motor. I looked quickly at their web page and don't see one either. We have a couple of different applications using their motors being controlled by PF700s.

Post the part number of the motors in question so we can give you a better answer.
 
I have actually done this, recently, with a SEW motor that had their on-board drive system. This SEW was the only SEW in the system and all of the other motors were to be driven by 525s.
 
The built-in inverter attached to the motor was a marketplace experiment in the 90s by several manufacturers as an attempt to deal with reflected wave phenomenon with the idea that the distance from drive to motor was the problem, so put the drive right on the motor and it's no longer an issue. As a general rule, it was a flawed concept and died out quickly. Motors are hot, VFDs don't like heat... hmmm, what's wrong with this picture?

The motors were standard induction motors, so yes, you should be able to just remove the old inverter and terminate directly to the motor windings.
 
We have a mid 2000s machine with one of these SEW motor/drive combos, and quite honestly its worked very well. I am a little surprised after reading what jraef said(it makes sense), because ours is bolted to a chamber that goes close to 80c every 10 minutes or so, 6 days a week.

Anyway don't see any reason why you couldn't use another vfd to operate it.
 
Thanks for the responses. I'll be happy to get rid of these built-in inverters. The current speed control they are doing on the existing line with these drives is done via RS485 and a 1746-BAS module and it's painfully slow. You basically need to allow 0.5 seconds for each address on the network to send/receive, so you can see how long it takes for 13 motors to respond to speed changes. (Imagine trying to anything precise with this!)
 
We have a mid 2000s machine with one of these SEW motor/drive combos, and quite honestly its worked very well. I am a little surprised after reading what jraef said(it makes sense), because ours is bolted to a chamber that goes close to 80c every 10 minutes or so, 6 days a week.

Anyway don't see any reason why you couldn't use another vfd to operate it.
Probably the majority of them worked fine, but the one's that didn't failed in somewhat spectacular ways, then because the systems were built without room in the control panels for VFDs, retrofitting them became a nightmare for OEMs. Eventually the popularity waned so much that almost all of the manufacturers dumped the products.
 
This approach is still quite popular with Grundfos pumps. And I hate it. Configuration has to be done with an app on your phone using Bluetooth. There's no screen. If a drive dies then it's much more intricate to replace and I can't just use a different brand drive.
 
The built-in inverter attached to the motor was a marketplace experiment in the 90s by several manufacturers as an attempt to deal with reflected wave phenomenon with the idea that the distance from drive to motor was the problem, so put the drive right on the motor and it's no longer an issue. As a general rule, it was a flawed concept and died out quickly. Motors are hot, VFDs don't like heat... hmmm, what's wrong with this picture?

The motors were standard induction motors, so yes, you should be able to just remove the old inverter and terminate directly to the motor windings.

I worked on a project a few weeks ago that had may be 40 Lenze motors with built in drives, why I have no idea. Aside from heat they will get banged around as products are moved out on carts and pallets.
 
I remember using sew drive. When we tried to modify the controller settings, we had to order the "tech option" that cost over a grand in order to modify anything. But their support team was really good, they helped me set up everything on that controller and really put a lot of time helping me set it up.

Sorry this comment doesn't help you much with your solution.
 
I've run across many of the Sew inverter-on-board motors. Seen a few Lenze ones too. I worked at a plant full of the Sew units and never had one die that I can remember. I thought it was a pretty cool idea. I didn't realize they died out.
 
If you guys are talking about the SEW MOVIMOT, we used 1000s of these in conveyor application. We have them controlled in a discrete fashion, and are in an open air environment, minus rain. We have never had an issue with them. In this setting they work great.

Troubleshooting can sometimes be a pain to check for signals since you have to pull the inverter off to get to the terminals. We used junction boxes and terminal strips between the IO and drives so you can at least check it there. Also going online with the drive is SUPER easy and Motion Studio is free.
 
This product is still available and widely used. You are talking about SEW "MoviMot" products. They also have one with a DOL built in called a "MoviSwitch". The thing is basically a standard SEW asynch motor with a MoviTrac VFD built into it. They offer several variants with/without comms, various I/O, isolator, on machine and so on.

If you open the cover, and look under the drive system, you will see the wires for the motor coils are run to terminals.
 

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