Hello everyone,

so i know theres a lot of posts talking about A911 (Vdc_max), but they dont adress what to do if it happens while its running. 

We recently had a motor melt its coils together because the operator didnt notice the alarms and faults going off. we replaced the motor and hooked everything up like before. however now when we run it, every couple minutes it gives the alarm A911. i dont think that increasing the deceleration time will help since it runs for hours and the alarms comes all the time and not just during deceleration. 

we havent changed anything about the V20 inverter settings except ofcourse the motor properties.

the centrifuge contains a plate so heavy to the point it takes around 45 minutes for it to come to a complete stop. we do not have a brake resistor, as the last motor did not need one.

i hope this is enough information.

Thanks in advance!

When you say centrifuge, I have to ask (probably legally required) what type of materials are placed in the centrifuge?  I also hear about the plate containing something that is very heavy, and then I think heavy metals and wonder if this is a nuclear isotope separating centrifuge.

I suggest contacting Siemens Support using "Support Request" link in gray bar above (in the online forums).  Create "new request".  Be sure and be specific with them as they may be allowed to sign an NDA if required to provide specific support for nuclear centrifuges.

What does the manual for V20 state A911 means?

AlwaysErrors

Hello everyone,

so i know theres a lot of posts talking about A911 (Vdc_max), but they dont adress what to do if it happens while its running. 

We recently had a motor melt its coils together because the operator didnt notice the alarms and faults going off. we replaced the motor and hooked everything up like before. however now when we run it, every couple minutes it gives the alarm A911. i dont think that increasing the deceleration time will help since it runs for hours and the alarms comes all the time and not just during deceleration. 

we havent changed anything about the V20 inverter settings except ofcourse the motor properties.

the centrifuge contains a plate so heavy to the point it takes around 45 minutes for it to come to a complete stop. we do not have a brake resistor, as the last motor did not need one.

i hope this is enough information.

Thanks in advance!

Thank you for answering

Its not that the product on the plate of the centrifuge is heavy, its the plate in the centrifuge itself thats heavy and needs a lot of time to coast to a stand still. 

the centrifuge is used to seperate small particles from a vegetable extract (not sure the company wants me to say which one) the product is alike to water with a slightly higher viscosy. but the centrifuge will be empty by the time we let it coast. 

the A911 alarm is defined as "The Vdc_max controller works to keep the DC-link voltage (r0026) below the level specified in r1242" in the manual. 

my main question is how to prevent this while it is running. if the problem occured during the deceleration phase i would know what to do. but getting this alarm during production when its at a consistant speed is what baffels me.

ones again, thank you for the help

0_Einstein

When you say centrifuge, I have to ask (probably legally required) what type of materials are placed in the centrifuge?  I also hear about the plate containing something that is very heavy, and then I think heavy metals and wonder if this is a nuclear isotope separating centrifuge.

I suggest contacting Siemens Support using "Support Request" link in gray bar above (in the online forums).  Create "new request".  Be sure and be specific with them as they may be allowed to sign an NDA if required to provide specific support for nuclear centrifuges.

What does the manual for V20 state A911 means?

AlwaysErrors

Hello everyone,

so i know theres a lot of posts talking about A911 (Vdc_max), but they dont adress what to do if it happens while its running. 

We recently had a motor melt its coils together because the operator didnt notice the alarms and faults going off. we replaced the motor and hooked everything up like before. however now when we run it, every couple minutes it gives the alarm A911. i dont think that increasing the deceleration time will help since it runs for hours and the alarms comes all the time and not just during deceleration. 

we havent changed anything about the V20 inverter settings except ofcourse the motor properties.

the centrifuge contains a plate so heavy to the point it takes around 45 minutes for it to come to a complete stop. we do not have a brake resistor, as the last motor did not need one.

i hope this is enough information.

Thanks in advance!

 

Thank you for replying!

We already let the load "coast" to a standstill to prevent a big inertia. so we dont get the alarm during the coasting of the motor.  

would a braking resistor help with the alarm during normal production while its running at a consistant speed?

Tractor: "The reason for fitting a VS drive may require justification, is this required, or can a Direct drive be used??"

im sorry, but im not sure what you mean with this part. english is not my mother language,  so some of the engineering lingo isnt known to me yet. Is the VS drive just the inverter, whereas a direct drive is just a contactor?

Also, when you say "change the drive setpoint", are you talking about lowering the frequency or a diffrent parameter?

Thank you again for taking the time to help

Tractor

This will be the DC Link controller cutting in (A911) to extend the ramp down time, however stopping a high inertial load is tricky, possibly needs a resistor braking to absorb the regenerated energy.

Even changing the drive set point will have an impact.

The energy stored in a load of this type can be high, and the resistor rating for controlling this load requires calculation.

Or, is it possible to allow the load to ‘coast’, by disabling the V20 output?

The reason for fitting a VS drive may require justification, is this required, or can a Direct drive be used??

Come back if I can help further.

Tractor

Hello Everyone,

We have been able to test it with P1240 disabled, but now it jumps to F2 when running at nomral operating speed. we have decided to once again look into a braking resistor. However, my boss at some point bought a braking resistor without consulting the technical staff (quote: but it says siemens on it, that should work right?). so we have a 6SE6400-4BD21-2DA0 braking resitor for a g120. Is there some way we can make use of this one on a V20 inverter? or should i tell him we need to get the right on and order one thats specific to the V20 inverter line?

thank you allf or the help in advance!

AlwaysErrors

Hello Tractor 

My apolagies, i did indeed forget that. its a 

6SL3210-5BE32-2CV0 V20 inverter.

Tractor 

The part number of the V20, can you post this?

Or have I missed it?

Tractor

This resistor, 6SE6400-4BD21-2DA0, 27 Ohms, 24kW pk, 1200W continuous.

This will connect to Frame Size (FS) D & E

Tractor

Hey Tractor

does that mean the braking resistor for a G120 will also work for the V20 line? 

also, this may be a dumb question, but i cant find where to attach the cable to the braking resistor. 

Do i just need to connect it to the red circled bolts? i know the small connector with blue wires are the NO switch.