Siemens Drive Fault

[Viks]

We have a lot of Siemens drives (Micromaster 440) on Profibus and I have noticed that just in a few months time I have got two drives which have faulted (F0003) and the fault won't clear until you replace the drive. The fault indicated is " Undervoltage" but the mains voltage is okay and there are other drives connected on the same bus which run okay. One thing I have noticed is that every aftertoon the operator will switch OFF all the Mains Isolating Switch to the control panel (cuts off the 3 phase incoming mains, PLC power supply and I/O's) before leaving for home and will switch it back ON again the next morning. Is this a practical thing to do? Could this be a reason for the drives faulting. FYI, all the equipments and components were installed in 2007 and the plant doesn't run 24/7 (just running 44hrs/week. Anyone who has experienced this before?

 

[rpoet]

Powering down and powering up VFDs is one of the hardest things you can do to a drive. The inrush on power up beats on the input rectifiers and DC link capacitors. To say nothing of the thermal cycling all the components in the cabinet will see every time it gets powered up and down.

It's possible you've lost a part of the input rectifier on the failed drive(s), giving you the undervoltage errors. Probably better to leave the cabinet on all the time, unless you need to shut down for maintenance.


-rpoet

 

[Viks]

Thanks for your quick response rpoet. Upon seeing the operator isolating the control cabinet every afternoon, I asked the operator what was the purpose of doing so and he told me that one of the commissioning engineers from the OEM told him to isolate power to the equipment when not in use. The OEM is from Italy. This is the first time for me to come across this type of isolation. What I knew is that for an emergency stop, all power to the load should be isolated but the VFD still has incoming power on it and the output power is disconnected by placing a contactor between the motor and the VFD output terminal and de-energizing the contactor during and e-stop situation. For total isolation, simply lockout the mainswitch which will isolate everything. In this setup, even pressing an E-stop trips the mains supply so there is no input power to the drives. Are there different safety standards in europe? I hope someone from the continent will explain.

 

[rpoet]

Viks,
Normally, in an E-stop situation, you don't care too much about the drives, in terms of power cycling. You just want to remove motive power as quickly as possible, and render the system safe. It's pretty standard to cut input (mains) power to a drive with a mechanical (no solid-state relays allowed) contactor to e-stop it. Most drive manufacturers recommend AGAINST placing a contactor between drive and motor, as opening the contactor under load (motor running) can damage the output stage of the drive.

Repeated power cycling of a system is what leads to eventual damage... sometimes. Some drives are better designed and thus better protected from power cycles. Good practice, however, is to leave them powered under normal operation. Keep in mind, that cycling power during commissioning and troubleshooting won't do any appreciable damage. It's repeated power cycles (hundreds+) that may cause damage.

For reference, I have a bunch of Parker Gemini servo drives where I work, some of which are 10+ years old, and have been treated pretty poorly. I occasionally find DC link capacitors that are at the end of their useful lifetimes, and are starting to swell. I simply replace the caps and all is well. No ka-boom cap failures (yet).

It could be that the OEM just gave some bad advice; It's not the first time I've seen it. I can see no reason to shut the entire cabinet down when done for the day; if the machine is so poorly designed (and I'm not saying it necessarily is) that you can't walk away from it, maybe it should be modified.


-rpoet

 

[Viks]

Thanks for the info rpoet. About placing a contactor between the drive and the motor, we used to have a few seconds time delay before it opens to allow for the drive to switch Off the output first before the contactor opens. Now I know that it is not reccomended but the fact is we never had these drives fail. Another thing is that they were ABB not Siemens. There maybe a differene in design as you said. I think at present we will just advise the operator not to switch off the power to the cabinet and see if it makes a difference.

 

[rpoet]

About placing a contactor between the drive and the motor, we used to have a few seconds time delay before it opens to allow for the drive to switch Off the output first before the contactor opens.

If you have a time delay in place, the drive shouldn't care. I've seen poorly implemented E-stops that opened the contactor immediately, and that tended to frag drives pretty frequently.



-rpoet

 

[Highland Controls]

In general, if the drive is running in V/Hz mode, opening a contactor on the output is OK. If you are in vector, or some other non-V/Hz mode, then the drive needs to see a load.

Power cycling once a day is no big deal. The issue is when you cycle power frequently, with only seconds between cycles, that you will smoke a drive(servo or VFD). The DC charging circuit heats up with every power on, and if you don't let it cool off, something will fail.

 

[JesperMP]

Cutting the supply to a drive should not damage it.
Reconnecting it too soon could do some damage, but that seems not to be the case here.
The fault F003 just says that supply voltage is off. It is a warning that does not need to be reset.
I suggest to use STARTER, or DRIVE ES software to investigate the fault log on the drive.

If the drives are really repeatedly being damaged, you could send one to Siemens for them to analyse what it is that goes wrong.

 

[arihant]

which drive you are using is it MICROMASTER OR SINAMICS series???

 

[Viks]

which drive you are using is it MICROMASTER OR SINAMICS series???

The drives are Micromaster 440. I just found out last friday that all the drives in the control panel are configured for 400V supply voltage (P0210) whereas our local incoming supply voltage here is 440V. Although the drives have a tolerance of + 10%, could this be a possible reason for the drives faulting?

 

[ernitin29]

The drives are Micromaster 440. I just found out last friday that all the drives in the control panel are configured for 400V supply voltage (P0210) whereas our local incoming supply voltage here is 440V. Although the drives have a tolerance of + 10%, could this be a possible reason for the drives faulting?

this might be a reason but i dont think so that, this is the real problem but not simply tolerable, configure the drive bit higher than the incoming supply voltage. but what i think that if fault doesnt clears that means this is DC BUS VOLTAGE FAULT, there is capcitor which become open and faults appers u may look at this.

 

[JRW]

On the faulted drives-
what does r26 read??

 

[Viks]

On the faulted drives-
what does r26 read??

I haven't checked parameter r0026 yet but will check and confirm when I can. Thanks.