NewElec’s KE electronic motor protection relay is ideally suited to detect dry running conditions in pump applications. User-selectable dry run detection methods may be either by current or by power factor measurements. The relay detects dry run conditions on small kW motors and in applications where a large drive ratio is a factor, such as with V-belts or large reduction gearboxes. Nuisance load loss trips are avoided with ‘pump prime time settings’ and user-selectable trip time delays are all built-in. The relay can be selected to automatically restart the motor after a given time interval (only on dry run trip conditions).

Jam or running stall protection with user-selected trip levels and trip delay times, start per hour limitation settings, permissible consecutive starts, short circuit protection and statistical motor operation data are provided. Phase rotation, over and under voltage measurements are all included features. The thermal overload curves are adjustable Class 5 to 40 s.

Earth leakage and earth fault protection features are available with appropriate and distinguishing latched LED fault displays. The trip sensitivity threshold can be set in the range 30 to 1 000 mA. The curve may be set for instantaneous (trip delay settings 100 ms to 1 s) or IDMT. Incorporated into this is harmonics filtering allowing for far less nuisance trips when used with VSDs or high inrush currents. Even more protection is made available by adding the earth insulation lockout module that prevents starting of the motor when the windings are contaminated.

The relay also measures real and apparent power motor consumption and logs up to 2 000 events and 60 last faults with accompanying current and voltage measurements at time of trip.