SIRIUS 3RR2 current monitoring relays   
8.5 Configuration 
  SIRIUS Innovations 
696  System Manual, 01/2011, A8E56203870002-03 
8.5.2.1  Wear detection 
The current monitoring relay detects the onset of wear on the basis of changes in current.  
Example applications: 
●  Detection of blunt blades or tools in chucking machines (e.g.: turning, milling, sawing 
machines) 
●  Detection of a lack of lubricant 
●  Detection of bearing wear 
●  Timely replacement of resistance heaters 
The current rise at the end of service life can be evaluated to detect pending failures. 
8.5.2.2  Process monitoring 
Kneading resistance 
The current monitoring relay detects changes in process states on the basis of changes in 
current. This means that in cement or resin production, for example, the required state can 
be detected at a specific kneading resistance, so that agitation can be terminated as a result.  
Resistance due to pressure 
In car washes, the system uses the rising mechanical resistance and, in turn, the current, to 
detect how much pressure the rollers can be allowed to exert without causing damage. 
8.5.2.3  Overload detection 
The current monitoring relay detects possible machine overloads (affecting screw conveyors, 
conveyor belts, cranes, fans, for example) on the basis of changes in current. 
Example applications: 
●  Detection of excessive startup or transportation weight 
●  Detection of deposits on shovel blades 
●  Detection of insufficient viscosity 
8.5.2.4  Detection of load shedding 
The current monitoring relay detects undesirable load shedding on the basis of changes in 
current. By evaluating the drop in current, in particular by analyzing the active current, the 
current monitoring relay is able to respond to load shedding. 
Example applications: 
●  Machine downtime due to belt slippage or defective drive although the motor is running 
●  Dry-running of pumps