Why Does My Computer Monitor Go Dark When Turning On Ceiling Fans Connected to an UPS?
Many users have encountered the frustrating issue of their computer monitors going dark for a few seconds whenever they turn on ceiling fans connected to an uninterruptible power supply (UPS). This article will explore the reasons behind this problem and provide practical solutions to address it.
Voltage Fluctuation
One common reason for screen blackouts is voltage fluctuation. When you turn on the ceiling fan, it may cause a temporary drop or spike in voltage. Monitors are sensitive to these changes, and a significant fluctuation can momentarily disrupt their signal.
Inrush Current
Ceiling fans, like many electrical devices, draw a higher current when they first start up. This is known as inrush current. The sudden demand for power can cause a brief dip in the power supply, which can affect other devices connected to the same UPS.
UPS Limitations
Some uninterruptible power supplies (UPS) are not adequately rated to handle the combined load of a computer and a ceiling fan. Turning on the fan can momentarily overload the UPS, causing the power to drop as a protective measure.
Connection Issues
Momentary disruptions in power can also be caused by loose or faulty connections in the UPS or between the UPS and the monitor. Ensuring all cables and connections are securely fastened can help prevent these issues.
Solutions
Check UPS Rating
Ensure that your UPS has an appropriate rating for the total load of all connected devices, including the ceiling fan. A UPS that is rated for higher power can help prevent voltage dips and blackouts.
Use Separate Circuits
Connecting the ceiling fan and the computer to separate circuits can also help. This prevents voltage fluctuations from one device from affecting the other.
Inspect Connections
Regularly check all cables and connections for any signs of wear or looseness. Loose connections can be a contributing factor to momentary power disruptions.
Consider a Different UPS
If your current UPS is not adequately rated for your needs, consider upgrading to a model with more capacity. This can help mitigate voltage drops and blackouts caused by inrush current.
Preventing Momentary Shutdowns
In some cases, connecting the computer system and monitor through a surge protector can help prevent momentary shutdowns caused by surges or transients. A surge protector can provide an additional layer of protection against voltage fluctuations.
Close Circuitry Issues
Note that you should not connect your ceiling fan to the UPS. If the fan is not critical to your operations, it is better to power it from another circuit. Ceiling fans are typically too large a load and can drain the battery of the UPS quickly.
The startup current of a ceiling fan, also known as inrush current, can be up to 5-10 times its normal load. This large starting current can cause a significant voltage drop at the output of the UPS, which may not be tolerable for the computer monitor. The monitor may shut down as a result of this low voltage.
To resolve the issue, it is recommended to connect the fan to a separate circuit from your computer. A second, separate UPS would likely stabilize the power and prevent the monitor from shutting down.
Conclusion
Understanding the reasons behind screen blackouts can help you choose the appropriate solution. Whether it is a faulty UPS, inrush current, or insufficient power capacity, addressing these issues can help ensure a stable power supply for your monitor and other devices.
By following the solutions outlined above, you can minimize the occurrences of screen blackouts and ensure that your computer operates smoothly when turning on ceiling fans or other large electrical devices.