Mm440 drive speed vary

[deno]

Sir ,
Here can I used same rating 6 pole motor to get high torque at low speed ?
And our problem is that we don't have 1:80 ratio gear box in spare right now that why we are using 1:40 ratio. In that we are getting high speed but not getting required torque. Which is able to move the roller with load.

Sir if you have any other options to solve my problem please tell me
Thanks

 

[deno]

Sir,
We have 90 kw mm440 drive which usrd for bevelling m/c spindle rotation. Drive run ok but now a days it frequently trip at f0003 under voltage I have check incoming power found ok 415 .
Please suggest any solution.

 

[robertmee]

Sir,
We have 90 kw mm440 drive which usrd for bevelling m/c spindle rotation. Drive run ok but now a days it frequently trip at f0003 under voltage I have check incoming power found ok 415 .
Please suggest any solution.

Do you have a line choke installed prior to drive? Mm440s are prone to rectifier failure due to varying incoming line voltage. Also how are you monitoring the incoming voltage? Just checking it periodically tells you nothing. You need a recording device to see if you are having dips in voltage due to other loads starting or transformer issues or service issues.

 

[JRW]

What is p210 set at?

 

[deno]

Hi robo,
Yes we have line choke at input side of drive. I have try to bypass the choke but still the problem is same.i have measure line voltage periodically through DMM. and also having analog volt meter on panel. This also show there is no voltage drop. Kindly suggest any solution.

Also sir JRW

IN p0210 having 400 volt. And I have try it to increase /decrease this between 380 to 415 volt but problem is still same.

 

[robertmee]

Swap the drive with a spare and see if the problem goes away....

 

[deno]

Hi,
I think replacing the drive is last option .because forthat I need to convenience to my boss that drive has faulty.
In the mean time I have observe that in without load drive has running smoothly and it dc link voltage become 570-580 volt.but when motor goes in load dc link voltage become 400 volt .I think this is create problem?
I think all igbt are not fire or weak? Please suggest what are the reason to drop dc link voltage? And also how I check all igbt are healthy.?
Thanks in advance

 

[GaryS]

It looks to me like you may be single phasing the input
Look at the current in the 3 power feed lines they should be close in value just because you have voltage doesn't mean you have current.
You could have one of the input power rectifiers has opened the available power would be down by about a third. The caps on the DC Link bus would charge OK with no but when the drive loads the voltage would drop off. With Lower buss voltage the drive lower the output frequency. The current should be balanced between the 3 legs both input and output.

 

[jraef]

Adding a VFD will not solve your problem, it will make it worse. You had an 80:1 gear reduction, which also meant you had an 80:1 torque multiplication ( keeping it simple here, don't get caught in details). You have replaced that gearbox with a 40:1 ratio, you now have 1/2 the amount of torque at the work shaft. We don't know how much torque you needed, but apparently 1/2 torque is insufficient.

If you use a VFD to double the speed, it cannot increase the torque, and in fact since you cannot also increase the voltage as the speed rises above normal, you will actually LOSE torque. If you double the size of the motor to double the torque, but it is the same speed, you are still short of what you need. You need to double the speed AND double the size, but no VFD. If you want to double the speed using a VFD, quadruple the size of the motor.

Or... Just go get the right gearbox.

 

[deno]

Hi,
Jraef I have just replaced the gear box by 60:1 which is available at shopefloor.

 

[deno]

Hi garys,
I have check the input/output line current it almost balance . But I think one of drive igbt get weak when drive have load it become open. But I am not sure so please how to check check and confirm that igbt has fail?

 

[Steve Bailey]

Jraef I have just replaced the gear box by 60:1 which is available at shopefloor.

And now you have 75% of the torque you formerly had instead of 50%.
If the original designer of the system included a generous margin of safety in the design, you may be able to turn the rollers. Be aware though, that you will have increased the load on the motor and lowered the speed. That means the fan won't be drawing as much cooling air over the motor at the same time that the motor will producing more heat. That will reduce the motor's life.

 

[deno]

And now you have 75% of the torque you formerly had instead of 50%.
If the original designer of the system included a generous margin of safety in the design, you may be able to turn the rollers. Be aware though, that you will have increased the load on the motor and lowered the speed. That means the fan won't be drawing as much cooling air over the motor at the same time that the motor will producing more heat. That will reduce the motor's life.

Hi steve,

Yes you are true for that I have check the fan and motor .it's not overheated and the motor is not continues running. But thanks for your reply as we think about design point of view.

Please also reply me about my latest query about mm440 drive trip at f0003 and how to check drive all igbt are work ok.

 

[deno]

Hi please help me

Now I am facing new problem in same 90 kw drive the drive is trip f0001 overcurrent fault without running motor .so I have check motor and motor cable find ok. Also increase ramp up time. But problem is same .some time drive work ok in load condition also and motor taking rated current but some time drive trip in ideal condition at f0001.

Please help my m/c under break down.

 

[deno]

Hi please help me

Now I am facing new problem in same 90 kw drive the drive is trip f0001 overcurrent fault without running motor .so I have check motor and motor cable find ok. Also increase ramp up time. But problem is same .some time drive work ok in load condition also and motor taking rated current but some time drive trip in ideal condition at f0001.

Please help my m/c under break down.

Hi no one is here to give any suggestions.

Ok in mean time I have check my drive found that when I disconnected the CT cable from control card the fault f0001 has gone or reset.further I have check found that V phase having problem either due to CT /IGBT get faulty . So please anyone give me idea how I check and confirm IGBT ant CT ?

I am waiting your reply expert's