ABB 7
Motor Protection
REM615 ANSI
Product Version 2.0
1MAC251744 -PG Rev. A
Issued: 03.01.2010
4. Application
The REM615 relay constitutes main protection 
for asynchronous motors and the associated drives.  
Typically, the motor relay is used with circuit-breaker or 
contactor-controlled distribution motors and contactor-
controlled medium sized and large low voltage motors in 
a variety of drives such as pumps and conveyors, crushers 
and choppers, mixers and agitators, fans and aerators.  
  e motor relay is thoroughly adapted for ground fault 
protection.  Using cable current transformers, sensitive 
and reliable ground fault protection can be achieved.  
  e ground fault protection can also utilize phase current 
transformers with a residual connection for the ground 
ct input.  In this case, possible unwanted operations of 
the ground fault protection at motor start-up can be 
prevented using the relay’s internal interlocking features 
or suitable stabilizing circuits.  Figures 3 and 4 show 
typical REM615 application in substations with motor 
protection requirements.
More comprehensive protection of medium sized motors 
is possible with the VT inputs options. Voltage, power 
and energy metering and phase, sequence and ground 
voltage protection are available with these additional 
voltage inputs.
Figure 3. Protection and control application using the 
REM615 confi guration A
Figure 4. Protection and control application using the REM615 
confi guration C 
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IEC 61850
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REM
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REM
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615
M1 Mn
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REM
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REM
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615
REF
615
IEC 61850
M1 Mn