Warren1,

If you are looking for Horsepower [HP] from the KW rating, try the simple calculation of:

Take the KW rating, convert it into simple Watts by moving the decimal point 3 places to the right [or multiply by 1000], then divide that number by 746. The result is the HP.

Example:

HP = [KW*1000]/746

2.984 KW = 4 HP

2.984 * 1000 = 2984

2984 / 746 = 4

If you already knew this junk, please ignore the above calcs.

Now, if your looking for KVA, from which you derive load calcs, Panel Schedule calcs and an Ampere Rating figure, that will be really tough to pull off with only a KW rating.

One must know the KVARs included with the drawn KWs, in order to find the total line KVA load.

The Reactive Power [KVARs] will vary from Machine to Machine, resulting in various KVA ratings.

In this case, you will need documentation - either from Manufacturer's Manuals, or from a Nameplate's ratings.

A good example of 2 different KVA per KW ratings I have run across recently reflect separate 400 watt High Pressure Sodium fixtures [HID lighting].

1: Most commonly used, run-of-the-mill HPS Ballast kits for the 400 watt lamp are the typical "Quadri-Volt" Ballast [per Advance Transformer Co.], which is a 4 Input Voltage type Autotransformer [CWA to be exact], and use a 55 MFD [Micro Farad] Capacitor to bring the Power Factor from Nominal - or +/- 50%, to High Power Factor - or +/- 90%.

This CWA setup draws 480 VA [0.480 KVA]. The lamp is driven with around 400 Watts, and the Lamp / Ballast combination at High PF draws an additional 80 VARs[ Volt-Amps Reactive] - making the complete Volt-Amp load on the circuit 480 VA.

2: Due to some incorrect ordering, 3 fixtures with CWI Configs were used to make up the slack.

These are to drive the same S51 lamp, but the Line VA load is now 465 VA. The PF correction Capacitor is 48 MFD.

This results in only 65 VARs while driving the lamp at aproximately 400 Watts.

As you can see, there's really no way to figure KVA from KWs, when dealing with Reactive Equipment.

If something in the fixture dissipates additional heat, this will be an increased Wattage draw, but not more VARs - so the Line KVA increases to reflect the additional Wattage drawn from the supply.

If the loads were Linear [nearly 100% Resistive, or very-very-very minimal Reactive Power], then you could apply KW's directly to HP AND to figure load Amperes.

Let me know if this was in the direction you were going with your Q [AKA does this help??].

Scott SET