Lenze drive/ AC motor problem.

[hotrod]

Yep my fault for not wording that correctly, not a1 a2 i just changed the phases, it has three phases leaving the drive to the motor and two leads + and - DC 680 coming into the drive.

 

[rsdoran]

Yep my fault for not wording that correctly, not a1 a2 i just changed the phases, it has three phases leaving the drive to the motor and two leads + and - DC 680 coming into the drive.

I give..

 

[504bloke]

Sounds like the drive is on a common DC Bus.


Not done anything on Lenze but SSD (Eurotherm) can do this on their 890 series.

 

[Leadfoot]

The encoder being wrong usually causes problems in BOTH directions. I am supprised it worked OK in one direction.

BTW, How did the encoder wires get phased wrong? Considering all was working right and then suddenly things ran slow with high amps in reverse.

 

[hotrod]

Hey thanks rsdoran, I'll be at plc's for Idiots.

 

[rsdoran]

Hey thanks rsdoran, I'll be at plc's for Idiots.

You said it, I didn't. NOTE, your question had nothing to do with a plc.

Well here it is, we got an a/c motor hooked to a d/c inverter,

NO, you do not.

Technically I am the last person to be nasty etc, but when warranted I can be.

Well they found that the encoder was out of phase, It has an a+ and a A- wires that have to be reversed when the phase of the motor is changed. It is a lenze 9300 series drive hooked to a Lenze 1.7 kw motor. they called lenze this morning to get the scoop on the encoder. thanks guys!!

An encoder uses A, NOT A, B, NOT B, Z, NOT Z but not A+ and A-, what I suspect is a tach generator. Overall I think you do not have a clue though, if the motor reverses any feedback device should not have to change wiring physically.

ALL through your discussion you never mentioned the drive or motor being worked on or that it was a new installation BUT did state it was a new problem that had been running properly. Whether tach or encoder it will NEVER just, out of the blue, be out of phase OR magically move its wiring to the wrong connector.

Personally I do not care what you think about what I say, you should feel good because I am one of the NICE ones in most cases.

As I stated before, use the proper terminology and state the problem fully. If you do not know then learn.

 

[hotrod]

Well I guess you said it all, i don't have a clue, since i have only 8 days training in the field of plcs which makes me an rookie, the encoder in question is an encoder, with ten wires connected to it, which are connected to the inverter. I did understand my question didn't possibly involve a plc but there is one in the loop. a mitsubishi. and after i called lenze they told me I would have to reverse the a- and the a+ wires on the encoder. after reversing phases on the output of the inverter. this was after the fact I replaced the faulty encoder to begin with. which was an old theleim encoder that had a different wiring schematic, things had to be changed to accept the new style encoder. and in the future i will research anything in question and properly explain it in proper detail so as not to offend anyone who may view my post in the future, enough said I promise to do a better job so as not to insult your intellegence.

 

[ward]

in the future i will research anything in question and properly explain it in proper detail so as not to offend anyone who may view my post in the future, enough said I promise to do a better job so as not to insult your intellegence.

Not to belabor the issue but it's worth pointing out that it's probably not so much an issue of offending or insulting anyone's intelligence as it is frustration at not being able to help properly. Everyone (I think)understands the learning curve for anyone beginning this field and sincerely wants to help; they press for more accurate and detailed info in order to provide better answers.

I, for one, learned (or remebered) a few things from some of the posts even if they didn't quite explain your particular situation.

 

[DickDV]

OK hotrod, let's let the personal stuff go and get back to the problem. I misunderstood some of your earliest material so let's see if I've got the pieces in place correctly now.

It sounds like you have a Lenze 9300 AC drive connected to an AC induction motor.

It sounds like you have a simple pulse encoder providing speed feedback to the drive. This encoder has only A and NOT A signals, no "B" channel, no quadrature, no home reference pulse Z.

It sounds like the Lenze AC drive is powered by a 680V DC power supply rather than the usual AC supply.

It sounds like you are testing the motor bare-shafted---no load of any kind.

It sounds like you are observing high motor amps in one direction and low motor amps in the other direction.

Do I have the "facts" of this case correct to this point?

If not, please be specific with what I've got wrong.

Thanks, DickDV

 

[kamenges]

In case hotrod floats off into the mist and doesn't return for a while:


The Lenze 9300 inverter is a full feature flux vector drive. It sounded to me like hotrod is operating the drive in flux vector mode with a true quadrature encoder feedback. Further, it sounds like someone didn't like the command direction versus actual direction of the motor. So 'they' swapped two of the motor leads (to change direction) but didn't change the encoder phasing (of a previously working system) to match. Swapping the encoder A and /A lines corrected the motor rotation to encoder direction relationship and he is again good to go.

I suspect something was changed on this system that 'had nothing changed on it' unbeknownst to the people working on it.
Keith

 

[Leadfoot]

For those that have not yet seen them, some encoders do in fact use + and - signs instead of the familiar A and A NOT.

I do not have a computer keyboard that allows me to put the line over the A to signify NOT. Does anybody have one? I imagine this allows easier designation of the phases.

Since hotrod is admittly a rookie, it is easy to see why he has had some issues with describing what is going on and what was done. I do believe all of us have been there once upon a time.

 

[tb844]

Thanks, this fixed my problem with a Lenze 9300 servo to a motor that was changed by my customer. It had a Theleim encoder also on the old motor but the new motor had a different encoder.

What I learned from all this....I will never put a Lenze product in anything I build new.