Siemens Vector Drive : Trouble shooting tips

Dear All,

I am having a 110kW vector drive SIMOVERT running at 50% at its full load capacity...The problem is I could not get current reading at AC side (I mean Input side) in one phase...The other two phases are carrying the current.

The drive is not giving any alarm or fault indication...What could be the reason for it? Can there be any problem with the power semiconductor devices?

I would like to know your valuable experiences.

Thanks.

Part number of the drive please ?

can you isolate incoming power to the drive and make sure that
all of the power wires have voltage applied to them? If you are not getting power to one phase, I would check for a blown fuse
upstream.

Sounds like it could also be an open diode in the input rectifier circuit on one phase.

On a drive that size, I'm sure that it monitors that all three phases are present on the input, so I'd doubt it's anything upstream.

The suggestion to switch the input phases around and then check for current flow will isolate a drive problem from a power supply problem.

I suspect that the drive has a bad input diode block but, at only half load the DC bus is not sagging down enough to trip. In fact, that is exactly how a three phase drive is derated to operate on a single phase source.

And, while I am not closely familiar with the Siemens drive, it is more the rule than the exception that a larger drive will tolerate the input being single-phased at light load without any fault or warning being generated. Or, if there is a fault or warning, it can be turned off in the software.

It sounds like there is no problem with your present situation even if the diodes are bad. I'd just keep using it and consider myself lucky! Unless, of course, the imbalance current is upsetting your power network.

It should also be noted that "most" 3 phase drives will run on a single phase input to about 50~60% rated capacity. Is the dead leg terminated on the feeder side? Is this a system that you just installed or are you troubleshooting? It may be running single phase intentionally, with the third leg being terminated as a spare in the event of a utility phase loss. If the lineman makes the changeover at the pole, the user won't have to re-wire his/her drive. Just a theory.

In any case, at 50% load, you're not going to see any ill effects.

I meant to ask you above:

What's the kW rating of the motor? If it's half drive rated output, I would be willing to suspect that the single phase input is intentional. Peace.

One phase L1 missing current on Siemens Drive

Hi dears, I have a problem in one of my Siemens drive(6SE7033) 160KW, Input 400VAC, 3 phase. There was an insulation paper damaged on this drive on the capacitor bank and caused to short the positive and negative copper bars. Due to this short circuit, the drive was not running. I replaced the insulation paper and now the drive is running but it is missing the current always on L1 on the input 400VAC of the drive. I replaced one by one all the electronics cards on the drive except the IGBT card that I do not have but same, I replaced all 3 rectifiers on the input of the drive but same, I reprogrammed the CPU but same. I changed the phase sequence on the input but the same phase missing the current on another location. Can any one help regarding this problem. The drive was running on a 160KW motor very good for many years. Thanks