Powerflex 700 AC Drive

[proplasint]

Can anyone help. I have installes a Rockwell Powerflex 700 on the Hydraulic pump motor of a injection stretch blow machine. On all the machines I have installed these drives on before I have had no problem, however on this machine the motor is a 12 terminal leroy somer LS200LU 45kw motor. Originally this was controlled via a star delta starter. I have connected the motor in 400V delta as per the instructions on the terminal box. (The other option was 200V star!)

Since installing the drive the line current has increased by a factor of 33%. Does anybody know of a reason why?

I have installed these drives on similar applications and never had a problem to date

 

[waross]

Hello proplasint
What is your system voltage? What are the rated voltages of your motor? What are the rated voltages of your other existing motors?
yours

 

[proplasint]

Hello Waross

the terminal plate shows the motor connected 415V delta or 220V star.

All the other motors that i have connected have been 415v star. However, since the original readings taken in star delta, the current readings in delta with an AC Drive should be comparable with the original star delta?

 

[waross]

Is the drive set for the right frequency? A 50Hz./60Hz. confusion may be the cause.

 

[cbarn24050]

Hi, you appear to have it the wrong way round. the star connection is the higher voltage. Check to make sure is not 415 star/240v delta

 

[proplasint]

Hi cbarn24050, Usually 415V star/240V delta is correct - or always as been in my experience, however in this case the connection diagram inside the motor terminal box indicates otherwise. It does make sense that that the motor is connected wrong, as this would verify the increase in current by a factor of 33%, however i am just going off what it says on the tin. I would like to try the alternative connection but am afraid of causing damage to the motor.

 

[waross]

The troubling point is that with a delta voltage of 415 volts, the corresponding star voltage would be 719 volts. With a parallel connection this would drop to 360 volts.
Despite that, I would probably be guided by the information on the motor nameplate.
Try this site for connections;

http://www.firstelectricmotor.com/images/motcon15.jpg

the parent site;

http://www.firstelectricmotor.com/motor_connections.htm

yours

 

[jraef]

I have seen large Weg motors on rock crushers where it was in fact 415 Delta / 720 star (actually they were re-labeled 460V delta / 797V star 60Hz for use in the US). I have no idea why because I have never seen 720V used anywhere. Maybe Brazil since that's where Weg motors are made? Confusing as heck because we are used to connecting to the hign voltage pattern here.

I don't think that is the situation here however.

Eng-Tips: Help for your job, not for your homework Read faq731-376

 

[DickDV]

proplasint, I recently had a situation with a 12 lead motor where it was not dual voltage at all but rather a dual wound motor, a star connected start winding and a delta connected run winding. Both windings are rated the same voltage and are completely separate. You should check this with a continuity checker to see if that's what you've got.

If it is, there is a second question to ask. The motor may be designed to deliver nameplate hp with both winding connected in the run mode or it may be designed to run only on the delta winding. You will need to get this answer from the motor manufacturer.

 

[proplasint]

Hi everybody, and thanks for your responses. Here are the motor connections:

Originally the motor was connected as this in star/delta

This is the connections for 400v star/delta
u1 v1 w1 - connected to contactor

v2 linked to y1
u2 linked to x1
w2 linked to z1

z2 y2 x2 - connected to contactor

************************************

connections for 200v star/delta

contactor connected to u1, v1, w1
u1 linked to u2
v1 linked to v2
w1 linked to w2

contactor connected to z1, y1, x1

z1 linked to z2
y1 linked to y2
x1 linked to x2

**************************************

I have connected the motor to the drive as follows for

drive connected to u1, v1, w1

u1 linked to y2
v1 linked to z2
w1 linked to x2

v2 linked to y1
u2 linked to x1
w2 linked to z1

********************************************

The alternative connections on the motor terminal box is for 200v and is as follows

Drive connected to u1, v1, w1

link u1, u2, y1, y2
link v1, v2, z1, z2
link w1, w2, x1, x2

*************************************************

hope this makes sense and thanks for your help