© Siemens AG 2011

0RWRUIHHGHU

0RWRU

0DFKLQH

00427

HJ

SXPS

_

G ST80 XX

 

Wear fields in the motor environment

Acquisition variables for wear fields

Contact erosion

The contact condition and thus the remaining life time of a contactor can be determined directly based on the degree of contact erosion. You can simultaneously use this to make a de- termination about the condition of the power distribution, the motor feeder, or the converter.

Number of starts, breaking current

The number of starts or the level of the breaking current indi- rectly gives you information about the erosion of the swit- ching contacts (empirical values, manufacturer's informati- on). Using empirical values, it is also possible to make state- ments about the load of the driven machine.

Number of operating hours (with/without limit value) The runtime effects the wear of the motor and the machine. The need for maintenance can be determined based on empi- rical values, user knowledge or manufacturer's information.

Number of overload tripping operations

Overload tripping operations can have different causes. They can give information about the condition of the machine or plant, or they can signal an incorrect setting or motor selec- tion. If necessary, the motor size should be changed.

Current limit/overload

Gradual changes in the overall application environment such as pollution or bearing damage can cause increased current consumption. Preventive maintenance can be planned and carried out so that faults such as those caused by an overload can be prevented.

Temperature

Corresponding sensors in the switchgear environment can give information about the condition of the contacts. War- ming of the ambient air can indicate that the switchgear is too heavily utilized. One remedy is to avoid simultaneous activa- tions, if applicable. The temperature of the motor or machine can also indicate wear.

Ground fault or insulation detection

In isolated IT networks, faults can be detected in the motor or supply line.

Underload/performance measurement

Performance measurements on machines can indicate broken couplings, torn belts, slippage in the coupling bay, dry run- ning of pumps, or fan filter contamination.

In addition, there is a series of special acquisition variables for specific components such as pumps and general sensors who- se measured values are recorded via analog inputs. In many cases, the analysis of the described acquisition variables de- pends on the user's estimation.

Acquisition variables

Devices for condition monitoring

 

 

 

 

 

SIRIUS com-

 

 

 

 

Motor contac-

pact starter

SIRIUS motor

3RW44 soft

SIMOCODE pro

 

tor with RLT *

3RA6

starter M200D

starter

3UF7 **

Contact erosion; end of service life

 

 

 

 

Current detection

 

 

 

Performance recording/power factor

 

 

 

 

Number of starts/breaking current

 

 

 

Number of operating hours

 

 

 

Number of overload tripping operations

 

 

 

Current limit/overload

 

 

 

Temperature

 

 

 

 

 

Ground fault detection (int./ext.)

 

 

 

 

 

Underload/performance measurement

 

 

 

 

 

Maintenance timer

 

 

 

 

General sensor technology via analog inputs

 

 

 

 

 

 

 

 

 

 

 

 

Acquisition variables which can be provided by Siemens protective devices and control cabinet devices

*RLT stands for remaining life time monitoring

**a power contactor is needed to activate the motor

Monitoring and diagnostics 23

Page 23
Image 23
Siemens SIMATIC PCS 7 brochure Contact erosion, Number of starts, breaking current, Number of overload tripping operations