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ASEA RIS & P&B Gold Protection Relays Time/Overcurrent Characteristic 2
- Thread starter GVP
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2
- #2
Hi GVP,
regarding the RI characteristic, I quote the following from the manual for the ABB SPAJ140 combined overcurrent and earth-fault relay:
The RI-type characteristic is a special characteristic used mainly for time grading with existing mechanical relays. The characteristic is based on the following mathematical expression:
t = k / (0.339 - 0.236 x I> /I) where
t = operating time in seconds
k = time multiplier
I = phase current
I> = set starting current
P+B Golds are now called P+B Engineering and you could try emailing them, requesting information at mail@pbeng.co.uk or check their website at
Hope that helps
SECV72
regarding the RI characteristic, I quote the following from the manual for the ABB SPAJ140 combined overcurrent and earth-fault relay:
The RI-type characteristic is a special characteristic used mainly for time grading with existing mechanical relays. The characteristic is based on the following mathematical expression:
t = k / (0.339 - 0.236 x I> /I) where
t = operating time in seconds
k = time multiplier
I = phase current
I> = set starting current
P+B Golds are now called P+B Engineering and you could try emailing them, requesting information at mail@pbeng.co.uk or check their website at
Hope that helps
SECV72
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