[Scott_bob]

It may be interesting to know what people pay for Electricity in various parts of the US.

In order to make comparisons we would need some guidlines:

1) Total Horse Power of your Equipment
2) Line Voltage (220 or 480)
3) Number of Hours of operation per month

Equipment efficiency varies a great deal, as well as power company rates.
But it may be interesting to see these costs relative to your location.
You Electrical guys, let me know what I am missing...

[Adobe Machine]

1) 40, not including a tig welder, a mig welder and a plasma cutter all 220 equip. Also not including some table and circular saws.
2) Line volts, 220 residential
3)before being hospitalized, at least 60 hrs or more per month
4) " " " average bill was $275-300/mo, after I could no longer "Play", dropped to $150/month ( my wife said "I tole you so")

Adobe (old as dirt)

[in2steam]

It may be interesting to know what people pay for Electricity in various parts of the US.

In order to make comparisons we would need some guidlines:

1) Total Horse Power of your Equipment
2) Line Voltage (220 or 480)
3) Number of Hours of operation per month

Equipment efficiency varies a great deal, as well as power company rates.
But it may be interesting to see these costs relative to your location.
You Electrical guys, let me know what I am missing...

If you are talking about a comercial shop in my area you pay by power factor, the worse the power factor is the more you pay, so you are going to be comparing apples to oranges in most cases with your question. Also line voltage has little to do with it, you pay by the service not so much the votlage unless you are on single phase residential then you pay by watts(consumed). Typically in wisconsin you get a 3 phase hook up at a flat rate for the power rating coming in. After a certain rating they monitor you to see your lag, these are built into the transformer, so voltage matters little on 3 phase hook up it just improves your PF if you run alot of inductive loads.
This is why you see companies that have larger metling operations only do it at night as its cheaper in a lot of casses, the power is usally nearer unity(100% PF)

For instance I have 6 services coming into my plant 1 480 3 phase, 2 residential 240 3 phases and 3 240 3 phases comercial, this isnt a typical "plant" as we on the edge of a res. area and have expaned several times. The res. services cost more then the comercial as they are on watt meters, wereas the comercial are current transformers, these only record lag.
This why you often see comapnies more concerned about power factor correction then how much they actually use. The funny thing is we "use" more on the comercial services then on the res. services.

chris

[Scott_bob]

Thanks Chris for that info.

There is a simple formula that I use to determine how many amps are required to run a shop. The formula is based on full load amps which does not really mean that you will ever draw the full load, but it is a good guideline. Another thing to consider are your local electrical codes which often require that the breakers in your panel be sized at 125% of the full load amp rating on any particular connection.

The formula is as follows.
Total HP and multiply by .745 and then multiply by 1000 and then divide by your line voltage. This will give you the total number of amps required.
Here is an example. Your total combined HP for your shop equipment is 65 and your shop voltage is 220.

65 x .745=48.525(Total Kw)
48.525 x 1000=48,425(total watts)
48,425/220v=220.11 Amps(watts/volt=Amps)

Lighting and other loads (coffee pot, micorwave) which can be estimated at 2,000 kWh per macine cell. You can simply add the this total to the total above before you divide by the volts. Simple rule: Watts/Volts=Amps

Minimal single Machine cell Example:
20hp Haas CNC VMC
+10hp compressor
=30*.745=22.35 (kW) *1000=
=22,350 (total watts)
+ 2,000 kWh (for lights and basics)
=24,350 / 220v =111 Amps

[in2steam]

You have some interesting ideas, this would work well in a small shop area, or cell, if you have dedicated power to each area through either a bus or panel. But it would not work in any plant area that I have worked in, mainly because you are thinking local, when I have lights wired its in banks, often 50-60 on one or two breakers. My machines have there breakers set to what ever the manufacture states, not 125% of that, after that you either rate the circuit to NEC like 15 amps on a 120 branch etc. Simple fact of the matter is that in complex machine you cannot figure out what a HP rating is, of course my presses run well over 100' long with multiple 3 phase motors every few feet.

I think you would be more accurate doing it the way my engineers figured load when I worked at leeson, because you are not taking to factor single phase motors, transformers, eff, and PF, which in inductive loads tend to add up(most 1 hp motors are rated at 1000 watts no?), they just simply take your HPx1000-(10%) this now you effective KW rating. So in your example of 65 HP you would have 65000 watts of power usage(or 295 amps- 10% or 266), this will put you into a realistic range of power rating and make up for variances in amp ratings of different types of motors/processes.
And to say that you never use FLA would also be in error, in the case of HVAC its almost always, pegged to FLA, I have 3 30 HP air handlers, running 30 HP worth of air at all times, and then the compressors to boot when called for.

Larger motors demand more attention for the obvious reasons, and they tend to be more eff. in the end.

If you were to do this in plant that runs allot of dynamic processes you would find you are fairly close. I do like that 2000 kwh for other stuff, its rare that you have problems with electrical fed to a machine in terms of trips, its always the dammed coffee machine.....

Chris