Hello,

I am facing problem in Siemens sinamic power module 230 that it trip at different interval of time and give fault of F7011(Drive: Motor Over Temperature). The inverter is running at 20Hz, on BOP it's showing 107.3V and 146.93A.

I observe one thing that motor draw current more than it's rated current. Kindly suggest where the problem is ? How to rectify it?

Regards,

RSID

The motor protection may be creating this. The current drawn by the load, and reduced operating frequency (20Hz), may be creating a fault. The cooling may be calculated as inadequate.

To test this set P0335 to 1, 'Force Cooled using separately powered cooling fan', this will remove the protection which is creating the fault. If this removes the fault, the load and low motor speed is 'rightly', creating the fault.

Be aware now that the motor temperature has been removed! this is for diagnostic evaluation purposes only.

If this proves to be correct, can the motor operating speed be increased?

Check that P1080, switching frequency is at 'factory default' or lower.

Can, fixed speed cooling be added to the motor?

For further support some detail would help here:

VSD part numbers?

What is the mechanical load, with belt or gear ratio?

Motor nameplate detail.

And, pictures always help.

Hello,

The application is of aeration blower, the motor is belt driven. The inverter (Sinamics Power Module 230 6SL3210-1NE31-5ULO) doesn't have any connection of motor temperature sensor but generating fault F7011.

As per my observation the output voltage scaling is not correct, As on 50Hz it will be 400v and on 20Hz it will be 155v but in real at 20hz it's generating 107v due to which it's running more than the rated current.

For reference motor spec is attached.

Considering the motor  and Drive:

Motor FLC = 128 Amperes

VSD maximum current = 145 Amperes

Current at 20Hz = 146.93 Amperes

The load is a 'blower' for aeration, which can be variable torque for a centrifugal load or, constant torque for a 'Rootes' type?

Vector control will provide a more dynamic control of the motor, does this improve the operation?

Consider the load:

It appears that the load is ok at 50Hz, no overload that is?

At 20Hz, it is creating an overload?

At low flow, do you have diffusers creating a restriction. I am thinking about these devices in waste water tanks.

Comment:

'Rootes' blowers; these devices are constant load machine's, and are positive displacement devices, different to 'centrifugal' machines which are also referred to as 'blowers'. If this is the case then the drive may not have the required capacity.

I have tried to visualize the situation here, and make some assumptions, which may be incorrect perhaps. I hope these comments and suggestions help. Thank you for the pic of the motor, these do help.