Q & A

Q: Can I use the new Jaz Drive with my K2000?

A: The K2000 (as well as the K2500 and K2vx) and Jaz drives do work together, however there are some problems you should be aware of. The Jaz drive has a feature built into its system software that puts the drive to sleep after 30 minutes of non-usage, meaning the Jaz will automatically shut down its platter motor. This is the motor that spins the disk inside the Jaz cartridges. This Sleep feature is used to extend the life of the motor. If you go to the DISK Mode on the K2000 when the Jaz is "sleeping," your K2000 will lock up. You must then repower your K2000 and power cycle the Jaz drive in order to start working again. This situation also exists with Zip drives.

Here's a temporary workaround for the K2000/ K2500 Jaz (and Zip) problem: After you have accessed the Zip or Jaz Drive, turn the drive off (or, in the case of a Zip drive, unplug the power cord). Before you go to the DISK Mode again, turn the drive back on and let it spin up a bit. You can now go to the DISK Mode with no problems. A second solution: After you have accessed the Zip or Jaz Drive, eject the removable media. You can double press the two left-most soft-keys to do this from your keyboard. Before you go back to the DISK Mode again, reinsert the removable media and let it spin up a bit. You can now go to the DISK Mode with no problem.

Q: I'm trying to buy a voltage regulator or a UPS that can handle my equipment but I'm a little confused by the ratings. I'm used to worrying about how many amps things are, yet I keep running into ratings called volt/amps and a power factor. What gives?

A: Wow! Great question, but the answer involves getting a bit tweaky. It would help to fully understand the difference between voltage (volts) and amperage (amps), but that is beyond the scope of our newsletter. For this discussion, suffice to say that different kinds of equipment present slightly different "kinds" of loads to the electrical supply that is powering them. An electric light bulb, for example, is a very different kind of load than an electric motor. What this boils down to is that sometimes all of the power supposedly available to be delivered to a device isn't able to be used by it (technically this is because it sees the voltage and amperage as being slightly out of phase with each other). So the device that may be rated for 10 amps at 120 volts may actually need a little more than that if one takes into consideration that to the device, the volts and the amps aren't completely in phase with one another.

So, a textbook definition of Power Factor is: A number between zero and one which represents the portion of the VA (volt amps) presented to the AC load which actually delivers energy to the AC load. With some equipment such as motors or computers, current (AMPS) flow into the equipment without being usefully converted to energy. This happens if the current is distorted (has HARMONICS) or if the current is not IN PHASE with the voltage applied to the equipment. Computers draw HARMONIC currents which cause their power factor to be less than one. Motors draw out-of-phase or REACTIVE currents that cause their power factor to be less than one.

The definition of Volt Amps is: A VA (volt amp) rating is the Volts rating multiplied by the Amps (current) rating. The VA rating can be used to indicate the output capacity of a UPS or other power source or it can be used to indicate the input power requirement of a computer or other AC load. For loads, the VA rating multiplied by the Power Factor is equal to the Watts rating. The VA rating of a load must always be greater than or equal to the Watts rating because Power Factor cannot be greater than 1.

I know this probably sounds like a lot of techno babble, but when you see a power supply (like a UPS) rated in volt amps (instead of watts and amps), it simply means that they aren't taking any Power Factor into consideration. It would be a little misleading to give the rating in watts, because that would imply that some Power Factor had been assumed in the rating (which is often done and can indeed be misleading). If you intend to be working with any device like a computer, motor, or anything that presents a highly reactive or inductive load to the supply, then you will need to allow a little headroom on your supply for this. Problem is, however, that if a device has its power consumption rated in watts, then that usually means they have allowed for the Power Factor of that device. In those cases you can usually just match the consumption rating (in watts) of the various loads to a wattage rating of a power supply (like a UPS). If the supply is rated in volt amps, then just multiply the volts and amps together (which will give you a "fantasy" wattage rating) and then compare that to the wattage ratings of the loads. Because these loads should have had their Power Factors taken into consideration when calculating their wattage ratings you should be fine.

If all of this is too confusing (as I suspect) then feel free to call us here at Sweetwater. These are advanced concepts that generally do not really have to be fully understood in order to use a UPS or similar device. We'll help you get the correct item.


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