Alternating Relay 2 motors with timing RA221

Alternating Relay RA221
Alternation Command for hydropressor plant with 2 motors - with timing

Operation
Whenever the alternation command (6-8) (ALT) closes, the output relays (1-3) and (1-4) arm alternately. If the alternation control (6-8) remains closed after the previously set time 'T' or if the simultaneity control (6-7) closes (YES). the two output relays (1-3) and (1-4) are connected simultaneously, the relays only disarming after opening the two control circuits.

In order to avoid hydraulic shocks, the relay has a device that delays the cut-off or start-up of the second electric pump by approximately 2s, even if the simultaneity command has been carried out together with the alternation command.

The RA221 relay is a model that will soon be withdrawn from production and may be replaced by the new RA25A multifunction alternation relay model.

Changes to replace the old RA221 Relay with the new RA25A