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Estimating Rectifier Operational Costs

January 30, 2009

I would like to know a formula for estimating Operational Rectifier Costs.

Example:

Rectifier for Anodic Cleaning
2000 AMPS and 5.5 Volts
The rectifier is on 75% of every hour.

My idea is like this... 2000 AMPS * 5.5 Volts = 11000 Watts * 75% = 8250 Watts

Rectifier Efficiency = 80%

Therefore I would require 10312 Watts per hour or basically 10 kW. $0.09 per 1 kW and therefore I would have about $1 per hour for the operation of the rectifier... but this seems way too low.

Any help?

Tom Kidd
Student - Budapest, Hungary

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First of two simultaneous responses --

That is a reasonable calculation for direct cost. Do not forget periodic maintenance, calibration, upkeep and amortization of the initial cost.

James Watts
- Navarre, Florida
February 2, 2009

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Second of two simultaneous responses --

The KWH of electricity used to provide the DC power is based on the AC input, not the DC output. Use the same formula to determine KWH but do it on the input not the output and therefore no worry about efficiency.
Wish we had those kind of electric rates in NY.

Gene Packman
process supplier - Great Neck, New York
February 2, 2009

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You need to divide your answer by the efficiency to get closer to the AC input power, and add the electricity for any accessory devices like a fan in the case of an air-cooled rectifier. So, your power consumption is at least 25% higher than your present estimate.

Lyle Kirman
consultant - Cleveland Heights, Ohio
February 5, 2009