P=I x V

[irelandnewyork]

I am installing some coffee makers in a bar restaruant and the spec sheets from the manufacture state
120/208-240, 480 volts 18.6 - 58.5 amps. For a heater element does the P=IxV equation work or is there considerations to take into account depending on the type of load. Also is there a height requirement for hand dryers in a bathroom that is ADA compliant. Thanks in advance

 

[gar]

121028-2347 EDT

For a purely resistive load P = V * I for either AC or DC.

Your 480 @ 18.6 = 8928 W
120 @ 58.5 A is = 7020 W

These are close. There is probably some way to switch several resistors in different combinations for the different voltages.

Four 8.205 ohm resistors in parallel = 2.051 ohms and at 120 V = 14,400/2.051 = 7020 W.

Four 8.205 ohms in series is 32.82 ohms and at 480 V = 7020 W.

Four 240 V probably use the parallel of two sets of two in series. You get the same 7020 W.

At 208 probably use the 240 connection and require a slightly longer heating time. At 208 the power would be (208/240)² * 7020 = 0.75 * 7020 = 5272 W. This will take approximately 1/0.75 = 1.33 times longer to heat.

Check my math.

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