WEG DWE-3 Motor Protection Relay Amperometric Extension Module

The WEG DWE-3 Amperometric Extension Module is an accessory for the DWE-3 electronic motor protection relay that extends the motor current measurement range to cover very large motors from 630 kW to over 2000 kW using standard 5 A secondary current transformers. In Saudi Arabia, the largest motors used at Aramco gas processing facilities, SWCC desalination stations, and SEC power plants operate at motor currents of several hundred to over a thousand amperes, requiring external current transformers with 5 A secondary output rated for the motor primary current.

Technical Extension Details

The extension module connects to the DWE-3 base relay and accepts 0–5 A CT secondary inputs in place of the standard direct-connection current inputs. The module's burden is less than 1 VA per phase, compatible with standard 5P or 10P protection class CTs. The scaling factor is programmable via the DWE-3 front panel or communication interface to match the CT primary/secondary ratio. All DWE-3 protection functions (overload, unbalance, phase loss, thermistor, ground fault where fitted) operate identically with the extension module, providing the same comprehensive protection for very large motors as for medium motors.

Saudi Large Motor Applications

Saudi Aramco's main oil pipeline station motors (typically 630 kW to 1500 kW), SWCC's main seawater pump motors (1000–3000 kW), and SEC's cooling tower fan motors for power plants (200–630 kW each in large arrays) all exceed the direct-connection range of the DWE-3 base unit and require the amperometric extension module for protection. Razz Middle East provides CT selection assistance, burden calculation, and relay setting calculations as part of the DWE-3 supply package for these large motor applications.