Difference between an inverter and a UPS is very simple, when a layman talks about this difference. Any person will tell you that both the inverter and the UPS are used to give your electrical and electronic appliances and gadgets a backup power support when there is an electricity failure in your office or home. A layman will also tells you that the electricity backup from the UPS is instant and it does not let your electronic gadgets to get switched off and the electric supply is continuous and that is why it is given a name UPS which stands for uninterrupted power supply. However, the backup supply of power from an inverter gets delayed by one or two seconds, which causes your electronic gadgets to get switched off and you have to switch them on to start them again. This is the reason that most people use UPS to support backup of electricity to their computers and other costly electronic equipment, which otherwise get damaged due to sudden power failure.
Let us now define the difference between an inverter and a UPS from the technical point of view:
UPS: The one power cable of your UPS is fixed in the power socket of your wall when the power is on. So, the UPS keeps on getting a regular power supply from the mains when the power is on. This AC power received from the mains power source continuously keeps on being converted to DC. This DC power keeps on charging the battery of the UPS in a continuous charging mode. So, the battery of the UPS is always kept charged during the time when the power is there in the mains. The output from the battery goes to the Sine wave inverter of the UPS. It converts DC to AC and this feeds the equipment. This makes it very clear that the power to your electrical gadget which is connected to the UPS is always supplied from the battery. Due to the power always being drawn from the battery to the electrical equipment, there is no time lag in case of electricity failure and the flow of the mains power stops. It is only the battery of the UPS which stops from being charged since there is no power in the mains. However, the backup power from the battery of the UPS keeps on being supplied uninterrupted till the battery is discharged and is no more able to supply the power to the eqauipment. This is why we find that the backup power of the battery of the UPS is of very short period ranging from 15 – 20 minutes upward. The more is this backup time of the UPS battery, the more will be the cost of the UPS. Otherwise also, the circuitry of the UPS is expensive making the UPS even of a small backup time more costly.
Inverter: As far as the power to the inverter is concerned, like UPS it also comes from the mains for the inverter battery to get charged when there is no power cut off. The main difference between the inverter and the UPS lies in the fact, that in an inverter, the power is directly sent to the output which is connected by wiring to various appliances. At the same time the AC is also converted to DC and this DC is constantly charging the battery. On the other hand, the power to the appliances is not directly sent to the output but it goes from the battery of the UPS which keeps on getting discharged. A sensor and relay mechanism checks whether the mains is ON or OFF in an inverter. When the mains get switched off, the relay mechanism triggers to switch from mains to inverter. Rest is same like the UPS. Because of this sensor and relay, there is a gap between triggering.