he parameters of the ABB REM610 C51HCNN02 motor protection relay are as follows:
- Rated Voltage: 100/110/120/220/240V AC
- Control Voltage Range: 20–265V AC/DC
- Making Capacity: 30A for 0.5s
- Sampling Frequency: 5Hz
- Response Time: 8 seconds
- RTD/Impedance Sensing Current:
- Maximum 4.2mA rms (100Ω platinum RTD)
- 6.2mA rms (10Ω copper conductor)
- Thermal Overload Protection: Based on thermal stress calculation, with optional speed switch interlocking.
- Phase-to-Phase Overcurrent Protection: Time-delay characteristic with speed switch interlocking for three-phase phase-to-phase overcurrent protection.
- Undercurrent (Loss of Load) Protection: Time-delay characteristic.
- Ground Fault Protection: Directionless ground fault protection with time-delay characteristic.
- Negative Sequence Protection: Inverse-time characteristic for three-phase unbalance and reverse phase sequence protection based on negative sequence current.
- Temperature Protection: Supports PTC thermistors and different types of RTD sensors, such as:
- 100Ω platinum TCR0.00385
- 120Ω nickel (US) TCR0.00672
- 108Ω copper TCR0.00427
- Measured Quantity Inputs: Six measured quantity inputs, with password protection selectable via the HMI to display electrical quantity information one at a time.
- Current Inputs: Four precise AC current inputs.
- Digital Inputs: Three additional electrically isolated digital inputs; the RTD module option includes two additional electrically isolated digital inputs.
- Signal Output Contacts:
- Two normally open/normally closed signal output contacts
- Three normally open heavy-duty output contacts, which can be freely combined for output contact functions according to actual working conditions.
- Communication Protocols: Supports SPA bus, IEC 60870-5-103, and Modbus (RTU and ASCII) communication protocols.
- Communication Interfaces:
- Front/back panel communication: selectable wireless or communication cable
- Backplane communication module: selectable plastic optical fiber or RS-485
- Insulation: 2kV (input to protective ground)
- Electromagnetic Compatibility (EMC): Meets requirements of 1MHz burst interference test (Level III), electrostatic discharge test (Level IV), etc.
- Net Weight: Approximately 4 kg (estimated, as the specific net weight of C51HCNN02 was not found; reference similar model REM610C55HCNN02).

