KVA and KW is not the same thing?
About UPS Power Nominal Issues How do I choose the right UPS capacity when I have a network UPS power for my server? If you choose improper, usually the following two conditions, one is too small, the so-called small horse carts, is likely to cause damage to the equipment; the other is the capacity is too large, anti-aircraft guns, causing funds waste. Therefore, the correct choice of UPS capacity for network managers is an important thing. Often the UPS power supply on the market, the smaller capacity to "W" as a unit to mark; more than 1 kWh, with "VA" logo, "W" and "VA" value is different. This requires us to distinguish the specific situation to choose UPS. For small-capacity UPS users are more familiar with the concept of w (W), so small-capacity UPS generally use "W" that capacity, but this is not correct, with "VA" can more accurately show the UPS load capacity matching Degree, because the UPS output capacity is determined by the current value (A), so use "VA" that more appropriate
May 9, 2017
In fact, "W" is always less than or equal to "VA". The conversion relationship between them can be calculated using the following formula: W = VA × power factor. The power factor is between 0 and 1, which represents the percentage of useful power (W) for the load current. Only the electric heater or light bulb and other power factor of 1. For other equipment, there is a part of the load did not work. This part of the current is harmonic or reactive current, which is caused by the load characteristics. Since this part of the current, so "VA" value than the "W" value, "W" can be seen as "VA" value when the power factor of 1 when the special case. In general, the computer's w (W) value is 60% to 70% of its "VA" value.
May 9, 2017
In fact, all the power factor of the computer power factor is about 60% to 70%, microcomputer tends to 60%, mainframe tends to 70%. The newly developed UPS has a power factor auto-correction function, its power factor is called 1. Some UPS manufacturers use "W" to represent capacity, and in fact they refer to "VA" values. The computer load "W" value should be 60% to 70% of the indicated value, so the value is 100 W UPS power supply, can drive a 100 watt bulb, but can only drive 65W computer. At present, most of the computer equipment capacity with "VA" said that some computers also use "W" that capacity (such as IBM), but in general or "VA" more, so UPS with "VA" that capacity better reflect The degree of matching with the load. All UPSs produced by APC in the United States provide both "W" and "VA" values.
May 9, 2017