PEF-319 universal automatic electronic phase switching device is designed to supply an industrial and domestic single phase 220/230/240 V, 50 Hz load from three-phase four-wire mains 3×380+N in order to maintain uninterrupted power supply of essential single-phase loads and protect them against unallowable voltage variations in the mains. According to the voltage presence and voltage quality on the phases, the PEF-319 will automatically select the optimum phase in limits range set by user and switch the single phase load supply to this phase:- If power is less than 6.6 kW (30 A), the load is energized directly from the PEF-319;- if power is more than 6.6 kW (30 A), the PEF-319 controls the magnetic contactor (MC) single phase coils of the corresponding power (MC are not included in supply complete package). The maximum and minimum voltage limits are set by user adjusting the potentiometers on the front panel as per requirement.
The electronic phase switch PEF-319 is a microcontroller-based digital device. User should make setting of trip threshold limits of PEF-319 – the minimal and maximal voltage values at which PEF-319 trips and switches off the load (or switches over to another phase). Phase L1 has the highest priority. It means that at normal parameters of voltage on all phases connected to PEF-319 (L1>L2>L3), the load will always be energized from phase L1. If on L1 the value is out of limits set by user, PEF-319 switches the load to the nearest by priority phase in not more than 0.2 seconds if the its voltage corresponds to the normal level. If the voltage on the reserve phases does not correspond to the trip set limits the load switches off. After the load had been switched to another phase and the voltage parameters had been restored on the priority phase, the load will be switched back to the priority phase in return time r (from 5 to 200 sec, settable) set by user. If r is in the position “∞”, the return to the priority phase will be performed only when voltage on the other phase goes out of the threshold limits.
In case when the voltage supplied on load goes lower than the minimal threshold limit the load switching over or switching off should be performed with a time delay of 12 seconds. When the voltage goes higher than the maximal threshold limit or goes 30 V lower than the minimal threshold limit, the load switching over or switching off will be performed with time delay of 0.2 seconds. During the load switching off the PEF-319 continues to perform the voltage control on all phases. When the voltage normalizes within the limit range on one of the phases.
