Why use an Uninterruptible Power Supply (UPS)?
Interruptions in the power to your lighting control console can be caused by a wide range of factors. Very brief interruptions will cause your console to reboot, and even if power is restored right away, you still have no control over your stage lights until the console has rebooted and is back online. Depending on the console type this can take a minute ore more. While 60 seconds may not seem like a long time, when you're in the middle of a performance it can seem like an eternity.
A UPS is the only device that can reliably eliminate the problems associates with power interruptions, providing you with reliable, temporary backup power. A quality UPS will also provide protection against spikes, surges, brownouts, and EMI/RFI noise.
In entertainment lighting applications, the UPS should be installed between the power source and the lighting control console, as close as possible to the console. Any console peripherals and monitors not plugged into the receptacle on the back of the console (not available on all ETC consoles) should be plugged into the UPS as well. Also, only the console and its related equipment should be connected to the UPS; no coffee machines, USB power adapters, etc.!
How to Select a UPS
If you decide to use a UPS, you must select one with adequate capacity for your system. To do this you must calculate the total maximum power consumption of your control equipment in either watts or volt-amperes. The UPS you select should have a rating that is at least 10% greater than the system's total power consumption.
Equipment Power Consumption
|Expression 2||60 watts|
|Obsession 600||120 watts|
|Obsession Remote Console||120 watts|
|Obsession Processor Units (two rack-mounted)||250 watts|
|Obsession Designer's||50 watts|
|ETCnet Remote Video Interface||50 watts|
|ETCnet Remote Interface||50 watts|
|Eos Classic||360 watts|
|Ion XE & Ion XE 20||120 watts|
|Element 2||120 watts|
|Cobalt 20||756 watts|
|Cobalt 10||240 watts|
Converting Watts to Volt-Amperes (VA)
To convert from watts to VA, use the preceding power consumption table to determine the power consumption of all devices that will be connected to the UPS. Next, divide total power consumption by .7. The resulting number is the approximate power consumption of your system, expressed in VA.
For example, an Obsession console with two VGA monitors draws 320 watts. A ten percent safety margin brings it to 352 watts, or 503 VA. The correct UPS would be a unit rated at 700 VA. As a more complex example, let's consider a system that consists of two rack-mounted Obsession processor Units controlled with an obsession Remote Console. The Remote Console has two monitors and a third is plugged into the connector labeled Diagnostic on the back of one of the Processor Units. With a total power consumption of 670 watts or 957 VA, the correct UPS would be one rated at 1.4KVA or greater.