MPL servo motor speed

Does anyone have any [successful] experience with an Allen-Bradley MPL-A320P servo motor and Ultra3000 drive?

We have used the MPL-A320H motor (3500 rpm) in the past without any problems. Now I have an A320P which is rated at 5000 rpm. However, I can't seem to get it to go any faster than 3000 rpm. Normally I would suspect a cable or connection problem, but when the speed is ramped up it faults at almost exactly 3000 rpm every time. I have spent hours tweaking the gains and other settings without any results. This is making me wonder if we got the wrong motor or something. The full P/N is MPL-A320P-HJ22AA. It does have the older 2000-line encoder, but I would assume that when they rate the motor at 5000 rpm, that includes the encoder too.

I would appreciate any suggestions.

-John

kolyur said:

Does anyone have any [successful] experience with an Allen-Bradley MPL-A320P servo motor and Ultra3000 drive?

We have used the MPL-A320H motor (3500 rpm) in the past without any problems. Now I have an A320P which is rated at 5000 rpm. However, I can't seem to get it to go any faster than 3000 rpm. Normally I would suspect a cable or connection problem, but when the speed is ramped up it faults at almost exactly 3000 rpm every time. I have spent hours tweaking the gains and other settings without any results. This is making me wonder if we got the wrong motor or something. The full P/N is MPL-A320P-HJ22AA. It does have the older 2000-line encoder, but I would assume that when they rate the motor at 5000 rpm, that includes the encoder too.

I would appreciate any suggestions.

-John

Click to expand...

I have an upcoming project with Ultra 3000 and MPL-A230P-VJ42AA though it is rated at 3000rpm.
Are you using SERCOS drives or what?
I'd like to know what you come up with since i absolutely hate Ultras with a passion but the end customer decided to opt for the Ultras instead of Kinetx (don't ask me why).
I cannot offer any advice, but if the motor is rated for 5000rpm the built in encoder is also capable of 5000rpm.
Any chance that in your hardware configuration you misconfigured the motor? (if you are using a Sercos setup, RSL5K)

Thanks for the response. Where are you seeing that your motor is rated at 3000 rpm? According to my information the P option is 5000 rpm. Are you limited by your encoder somehow? If you have something that says the P option is only 3000rpm I'd really like to see it.

We are not using sercos, we have the indexing version of the drive and are doing all programming with Ultraware. Very simple. Can I ask why you don't like the Ultra3000? To be honest I have had good luck with them, been using them for 5 years without any problems until now. Of course we aren't doing any coordinated motion or sercos, only indexing.

I have double-, triple-, quadruple-checked my motor configuration, I even tried to open the Ultraware MDB database to see what's in there but it is password-protected.

What kind of ultra drive and what kind of configuration (analog, indexing, sercos...)? Did you program the new motor type and specs? How are you adjusting the speed?

Drive is 2098-DSD-010X
Motor is MPL-A320P-HJ22AA

The drive is used and mounted on my test board. The motor is brand new. I configured the motor just by picking MPL-A320P-H from the dropdown list in Ultraware. We are just running motion profiles in indexing mode, nothing more complicated than that. If I run an index with gradually-increasing velocity and watch the Ultraware scope, I notice that when the motor speed reaches 3000rpm, the command velocity continues to rise (as it should) but the velocity feedback stays at 3000rpm. Eventually the drive faults with a velocity error because the difference is too great. What's driving me nuts is I don't understand why the motor velocity is seemingly limited to 3000 rpm, it should be 5000.

kolyur said:

Thanks for the response. Where are you seeing that your motor is rated at 3000 rpm? According to my information the P option is 5000 rpm. Are you limited by your encoder somehow? If you have something that says the P option is only 3000rpm I'd really like to see it.

We are not using sercos, we have the indexing version of the drive and are doing all programming with Ultraware. Very simple. Can I ask why you don't like the Ultra3000? To be honest I have had good luck with them, been using them for 5 years without any problems until now. Of course we aren't doing any coordinated motion or sercos, only indexing.

I have double-, triple-, quadruple-checked my motor configuration, I even tried to open the Ultraware MDB database to see what's in there but it is password-protected.

Click to expand...

Already found out that I got the wrong info!
Yes, absolutely right, it is a 5000rpm motor, Thanks for pointing that out.
I just like Kinetix, a lot simpler to setup as well as wire, SERCOS and always control all motion through the PLC.
If you use Y type motors with Ultra you have to spend a lot more time grounding and bonding the motor, drive, clamps, etc.
I/O connector on the Ultra needs to be terminated on a breakout board almost every time especially if you use a brake motor as there's no connector for just a brake. Kinetix offers a connector on the drive for the brake, plug cable in on both sides and you are done. Since I use Sercos and Logix5K there's no Ultraware configuration to mess with , everything done on the PLC.
The only thing that we do as per customer spec will be using the high speed inputs of each drive for "home" or "registration".
Other than that it is cleaner and less labor intensive to use the Kinetix. Besides, Kinetix 2000 is out now and it is a bit cheaper than 6000. If you don't need an auxiliary feedback signal use a Kinetix 2000 system and you are up and running.Price is about the same range as the Ultras, footprint is about the same, I just can't see a reason for using Ultras at all.
Keep posting though. I'd like to find out what's wrong with your motor. I do have the -SE version of Ultras. (SERCOS).

Where's Ken R when you need him????
I think the "Velocity Mode" on an Ultra rings bells now, not sure, but a while back there was an issue with "Just" the velocity mode.
Any chance you can dig up tech notes from the AB site?

Problem solved!

Well I was getting desperate this morning so just on a whim I changed the input power on drive to 208v (I had previously been using 110v since it's on my test board). And voila, 5000rpm with no problem. So apparently the max motor speed can be affected by the drive input power, although I can find no mention of that in my Ultra3000 documentation. It just says 100-240vac single phase.

kolyur said:

Well I was getting desperate this morning so just on a whim I changed the input power on drive to 208v (I had previously been using 110v since it's on my test board). And voila, 5000rpm with no problem. So apparently the max motor speed can be affected by the drive input power, although I can find no mention of that in my Ultra3000 documentation. It just says 100-240vac single phase.

Click to expand...

Sounds good to me, we will be using 208VAC single phase, good to know.
I've checked the manual and there's nothing about incoming power affectinh the output rpm, a major bummer though.
Thanks for posting.
As far as the "Velocity Mode" issue mentioned earlier, it could have been a firmware related issue, can't find the tech note.

For the motor to run at full speed you must supply the full motor rated voltage to the motor (this would apply to any motor be it servo or induction). If you use an MPL-B motor on a 230v drive with 230v supply it will only run at half the motor rated speed. So this lets you use a MPL-B rated at 5000rpm to replace a MPL-A motor rated at 2500rpm. If you cannot obtain an MPL-A motor but are able to get an MPL-B motor get one that is rated at twice the maximum speed that your motor is running at, it does not have to be twice your original motor speed.


Alan