Previous in Forum: Current Through Neutral Earthing Resistor   Next in Forum: Grounded Bus Bar Ratings
Close
Close
Close
11 comments
Rate Comments: Nested
Member

Join Date: May 2009
Posts: 7

Lenze Servo Motor and Resolver Problems

05/18/2009 7:06 AM

Hi guys
Got a question in regards to some automation hope you can help

I was servicing a pick and place stacker crane last night and needed to replace a lenze MCA asynchronous servo motor that controls a set of telescopic forks.

The said motor has a resolver for use with a lenze invert drive, i changed the motor with exactly the same spec as the original but come to power up and reference the motor and drive it ramt up to a 100% speed

Now normally when the crane is in manule and being referencing the motor will usually run at 10% speed, reason being for safety and more control it only runs at 100% when in automatic, so you can imagine my shock when it in shot strait up to 100% shooting a telescopic fork strait at me nearly put me through a wall .

No mater what i did it would go strait up to 100% when a put the old motor back on it referenced as normal so what could cores the motor to ram strait up to 100% when the invert isent calling for the motor to go higher that 10%, could it just be that the resolver is knackered so the inverter dosent no what speed the motors doing or could it be something els any help would be greatly appreciated

Chris

Register to Reply
User-tagged by 1 user
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.
Guru
Popular Science - Cosmology - New Member Technical Fields - Technical Writing - New Member Engineering Fields - Energy Engineering - New Member Engineering Fields - Electrical Engineering - New Member Engineering Fields - Control Engineering - New Member Engineering Fields - Electromechanical Engineering - Old Member, New Association

Join Date: Apr 2008
Location: Lexington, KY
Posts: 1639
Good Answers: 73
#1

Re: Lenze Servo Motor and Resolver Problems

05/18/2009 8:23 AM

Sometimes the manufacturer of a servo motor will use a different encoder (resolver)on a particular motor. I have had to re-wire the encoder to different pins on a connector in order to correct to the old system.

The controller is looking for feedback pulses from the encoder (resolver) to determine the attained speed. It sounds like the acceleration is fairly high which is not unusual for maximizing performance of a servo based system. When the controller, however, gets only part of its signals it may misinterpret the speed. Unfortunately, not all controller manufacturers design their devices to detect an unusual response to a given program.

Check the pin out of your new motor resolver against the pin out of the old one. They must match or you may encounter the exact kind of problem you describe. Also check that the resolvers have the same number of pulses per revolution. If you need to refresh your memory on resolvers, try searching the internet on "encoders".

__________________
A great troubleshooting tip...."When you eliminate the impossible, whatever remains, however improbable, must be the truth." Sir Arthur Conan Doyle
Register to Reply
Participant

Join Date: Apr 2014
Posts: 1
#11
In reply to #1

Re: Lenze Servo Motor and Resolver Problems

06/19/2014 9:16 AM

We have lenze async motors in our plant with the resolver attached we have also exsperenced the same problem with starting the motor up and it taking off we found it was a feedback error from the motor to the resolver. motor was trying to go 1 way and resovler was counting oposite causing the motor to race to match positions. this was causing the motor to ramp quickly. we found that we had to do a motor reference to set the zero position on the motor. hope this helps

Register to Reply
Anonymous Poster
#2

Re: Lenze Servo Motor and Resolver Problems

05/18/2009 9:02 AM

Is it possable to disconnect the brake and move the arm manually? if so you could check the resover position through its axis. Also check the zero positions and that the resolver coupling is not slipping

Register to Reply
Anonymous Poster
#3

Re: Lenze Servo Motor and Resolver Problems

05/18/2009 9:06 AM

Is it possable to disconnect the brake and move the arm manually? if so you could check the resover position through its axis. Also check the zero positions and that the resolver coupling is not slipping

Register to Reply
Guru
Technical Fields - Architecture - New Member Popular Science - Weaponology - New Member Engineering Fields - Control Engineering - New Member Engineering Fields - Electrical Engineering - New Member Engineering Fields - Electromechanical Engineering - New Member Hobbies - Fishing - New Member Hobbies - Target Shooting - New Member Hobbies - Hunting - New Member

Join Date: Dec 2005
Location: Clemson, South Carolina
Posts: 1722
Good Answers: 18
#4

Re: Lenze Servo Motor and Resolver Problems

05/18/2009 10:36 AM

When you say "exactly the same spec," does it have the same number of poles (e.g. does it run at the same RPM at a given frequency)? Does the new motor have its own resolver, and is it the same as the old one?

__________________
We have met the enemy and he is us . . . Walt Kelly
Register to Reply
Member

Join Date: May 2009
Posts: 7
#5
In reply to #4

Re: Lenze Servo Motor and Resolver Problems

05/18/2009 10:55 AM

Hi Bill

The motor is the exact same type motor issued from lenze exactly the same, so it should have been a simple swopt like for like out of the stores, as for the resolver its built in to the motor so is sold as one unit.

Interestingly I found a second same type motor today and fitted it with no further problems, which Leeds me to believe its definitely the resolver at fault.

Register to Reply
Guru
Technical Fields - Architecture - New Member Popular Science - Weaponology - New Member Engineering Fields - Control Engineering - New Member Engineering Fields - Electrical Engineering - New Member Engineering Fields - Electromechanical Engineering - New Member Hobbies - Fishing - New Member Hobbies - Target Shooting - New Member Hobbies - Hunting - New Member

Join Date: Dec 2005
Location: Clemson, South Carolina
Posts: 1722
Good Answers: 18
#6
In reply to #5

Re: Lenze Servo Motor and Resolver Problems

05/18/2009 11:22 AM

Sounds like you're right -- resolver problem . . .

No feedback certainly could result in the controller trying to make it run (at 100%, in your case), depending on the design (apparently theirs), and it gives you an opportunity to make a suggestion to the manufacturer to make such a problem not occur.

__________________
We have met the enemy and he is us . . . Walt Kelly
Register to Reply
Member

Join Date: May 2009
Posts: 7
#7
In reply to #6

Re: Lenze Servo Motor and Resolver Problems

05/18/2009 11:44 AM

thanks guys

Register to Reply
Guru
Popular Science - Cosmology - New Member Technical Fields - Technical Writing - New Member Engineering Fields - Energy Engineering - New Member Engineering Fields - Electrical Engineering - New Member Engineering Fields - Control Engineering - New Member Engineering Fields - Electromechanical Engineering - Old Member, New Association

Join Date: Apr 2008
Location: Lexington, KY
Posts: 1639
Good Answers: 73
#8

Re: Lenze Servo Motor and Resolver Problems

05/19/2009 8:25 AM

Sounds like the problem is "resolved"! Sorry, I couldn't resist!

__________________
A great troubleshooting tip...."When you eliminate the impossible, whatever remains, however improbable, must be the truth." Sir Arthur Conan Doyle
Register to Reply
Anonymous Poster
#9

Re: Lenze Servo Motor and Resolver Problems

10/13/2009 12:55 PM
Register to Reply
Participant

Join Date: Jul 2010
Posts: 1
#10

Re: Lenze Servo Motor and Resolver Problems

07/22/2010 9:24 PM

I just read ur problem. i used to work at lenze a couple of years.i think u have already found the solution for it but i would like to explain the possible reason.

1- the resolver connection can not be wrong. because u didnt say servo drive had no SD2(resolver fault). but it is possible the wrong connection of coins of the resolver to drive. in this case the motor runs another direction.

2) u may have servo position drive or the program of the system can follow a position.the servo motor probably wanted to reach as quick as possible the right position. this is only possible at 9300-es models. But it also is possible at 93xx-EP models.But at position drive has 32 position programming pages. when u had resolver problem and then sorted out it , u reseted the fault from the keypad or HMI screen . and then the program of the servo drive started from page 1 . if the speed choosed 100% it is so normal. u had to reset all ur machine`s program

it is so difficult to explain the reasons from here. the whole system must be check. as u know, the program of the machine have so many conditions.

if we have this kind of problems on our system, after sorting out it we should reset others as well. the machine must start from the first step of conditions.

i hope these would help u

U can ask any questions about lenze

Edit Post #10

Message From CR4 Admin: Please refrain from posting private contact information.

Register to Reply Off Topic (Score 5)
Register to Reply 11 comments
Copy to Clipboard

Users who posted comments:

Anonymous Poster (3); Bill (2); deakin09 (2); hagey (1); NotUrOrdinaryJoe (2); ohanci (1)

Previous in Forum: Current Through Neutral Earthing Resistor   Next in Forum: Grounded Bus Bar Ratings
You might be interested in: Motor Controllers, Servo Valves, Servo Drives

Advertisement