Diference between Vin and Vout

[JulioCesar]

Hello,

I have a Smart-UPS 3000 RM, and it has a fault, but I don't know what it means. The fault message is:

"A site wiring fault exists."

I was monitoring the voltage measurements, and there are variations between Vin and Vout. I don't understand why there's a difference in voltage if the load and current are constant.

Can someone help me with this problem?

[Teken]

You have two questions which are not directly related. VIN / VOUT relate to the voltage seen and generated by the system.

VIN: This is the input voltage coming into the unit.

VOUT: This is the conditioned output voltage from the system. A online (double conversion) UPS provides regulated and filtered pure sine wave output. You’ll almost always see the output on these units to be solid 120 / 240 VAC regardless of the input voltage.

Line interactive is what you have in your system. It uses a combination of AVR / Battery Only modes when a user defined threshold has been met. As such the input / output will never be the same vs a On-Line (Double Conversion) UPS.

If the unit is also defined to Green Mode. This too will cause the unit to provide different output voltages. Both types of UPS Topology offer RFI / EMI filtering to negate what people often call *Dirty Power*.

Site Wiring Fault: This crude message indicates one or more detected faults on the line. Bad / missing ground, unbalanced neutral, reversed polarity.

Ground: It can be missing such as using a 3-2 prong adapter. Ground is loose or actually missing in the feeder circuit. The single point Earth ground in the electrical panel is above 25 Ohms.

Neutral: The system detects more than >5 VAC on the neutral line.

Reverse Polarity: The hot / neutral wire are physically reversed in the circuit whether it be on the outlet or breaker. 

If you have more questions please do ask. If not and this reply provided the insight you needed please mark this as a solution. So it will help the next person asking the same. 👍