NewElec’s N Series electronic motor protection relays are designed to protect LV motors. They offer the user a choice of protection features, mounting options, and a choice of appropriate motor thermal curves with five models to choose from. When used with their own integrated current transformers, which incorporate an earth leakage core balance C.T in the same housing, and the inclusion of a 4 to 20 mA loop for monitoring motor loads, significant space and cost savings are achieved.
Designed to IEC 60255-8, the N Series relays are reliable and provide overload protection with user-adjustable cold and hot thermal curves linked to a comprehensive thermal memory. The user has the ability of selecting the appropriate thermal curve for the kW of the protected motor. This allows the motor to work hard but within its designed thermal envelope. Excessive jogging of the motor will not be tolerated, and the cooling time after an overload trip is never compromised.
Earth leakage protection with a 250 mA sensitivity and a 100 ms trip delay, including harmonic filtering, enables D.O.L starting of large kW motors without accompanied nuisance trips on start-up. N Series relays recognise the potential danger of opening the main contactor on potentially high energy faults. They provide co-ordination so that either the trip is blocked if the earth fault current exceeds a safe level, or use is made of a dedicated earth fault trip contact designed to operate the back-up circuit breaker on detection of such faults.
If required, LED and remote relay fault indication is available.