UPS for 1.1kW system
simulate this circuit &ndash; Schematic created using CircuitLab

Figure 1. Automatic standby arrangement.







simulate this circuit

Figure 2. A more European representation of the same circuit.

How it works.


With mains power present RLY1 is energised and RLY2 controls the motor.
When mains power fails RLY 1 drops out and the motor is powered from the UPS.


Don't expect your typical computer UPS to run the motors. You'll need one that can provide enough power to start the motor and handle the inductive load.



Note: 'k' for kilo, 'W' for watt. You have in one place written 'KW' which is a kelvin-watt which is nonsense. Capitals matter.