gas hp compared to diesel, steam, electric hp?

[Sawing 4 fun]

I was wondering if any one knows of a conversion chart that would help me see how Diesel hp is rated against gas, steam, electric hp?
For example, if I was powering my mill with 150 hp gas engine and I wanted to switch to diesel or electric or steam. How would you go
about it? Gas hp is not the same as electric hp and so on. Is there a chart to convert all of this?

Thanks for everyones input!!!  say_what

[POSTON WIDEHEAD]

I found this concerning Hp vs. Electricity. Is this something that might help?
                                    Conversion Chart / Table
hp to kW Conversion Chart / Table:   kilowatts to horse power Conversion Chart / Table:
hp = kW
1.0 = 0.735
2.0 = 1.471
3.0 = 2.206
4.0 = 2.942
5.0 = 3.677
6.0 = 4.413
7.0 = 5.148
8.0 = 5.884
9.0 = 6.619
horse power = kilowatts
10 = 7.355
20 = 14.710
30 = 22.065
40 = 29.420
50 = 36.775
100 = 73.550
500 = 367.749
1000 = 735.499
5000 = 3677.494   kW = hp
1.0 = 1.360
2.0 = 2.719
3.0 = 4.079
4.0 = 5.438
5.0 = 6.798
6.0 = 8.158
7.0 = 9.517
8.0 = 10.877
9.0 = 12.237   kilowatts = horsepower
10 = 13.596
20 = 27.192
30 = 40.789
40 = 54.385
50 = 67.981
100 = 135.962
500 = 679.811
1000 = 1359.622
5000 = 6798.108

Metric horsepower is exactly defined as 0.73549875 kW (kilowatts), that is roughly 98.6% of US mechanical horsepower. Metric horse power is widely used in auto industry to indicate power of car engines in Europe and Asia. French, Japanese, Korean, German, Swedish, Italian and other automobile companies use this unit. Metric horse power was first used in the 19th century in Europe, primary in Germany and them was adopted in Asia. British car manufacturers and dealers can intermix metric horsepower and US mechanical horsepower depending on particular marketed product. The unit can have different abbreviations -for example "CV", "PS", "pk" or "ch" but all translated to "horse power" or "hp" in English language. This online calculator-converter provides conversion of horse powers to kW and backwards kilowatts to hp.

[scsmith42]

You also need to look at torque, as this is an important factor when the blade starts boggging down in a cut.

[Ianab]

HP is HP, as long as it's measured on the same scale.

But as SC suggests, it's the torque curve that makes the difference. When you reach max load on a gas engine and revs start to drop, the torque drops even faster and the engine continues to bog until it stalls.

But with a diesel the torque curve is flatter and doesn't fall off as fast. While the slightly lower revs mean less load on the saw, and the torque can keep you cutting though that tough spot. This is why a diesel engine with a little less power can still run a mill.  It's simply how it responds to that peak loading.

Electric and Steam have completely different torque curves, usually with max torque around zero rpm, and falling off as the revs increase. Add in a big flywheel in the case of a steam engine, and again the way it responds at peak load is totally different again.

There is no exact comparison as the torque curves of different engines, even of the same type, are different, as a big slow revving gas engine may behave more like a diesel than a highly tuned turbo diesel does.

Ian

[steamsawyer]

Hey Sawing 4 fun,

Somewhere I have a chart that compares the different types of power, when I find it I'll see if I can get it posted for you.

All I use is steam. I have had one gas tractor on my mill, a 1941 John Deere A. I knew when I belted up it was too small but of course I had to prove it.

I have had my engine on the sawmill at the Florida Flywheelers park. That was right next to the Cat D8800 that we used when there was no steam engine to belt up. I think the cat engine is about 100 or 110 HP I don't know for sure. I do know that my 70 HP James Leffel will pull way more than the Cat deisel.

Electric and steam have about the same in torque performance. Steam has relatively the same torque at stall as it does at its governed speed. Keep in mind that Torque is the amount of work that gets done and Horse Power is a measure of how fast that work is done.






  

  

[steamsawyer]

A few videos that relate to torque and horse power... Demonstrated with a prony brake... This machine measures the torque on the shaft in foot pounds and the hp can be calculated with the tachometer reading.

http://www.youtube.com/watch?v=fXgRS4Wy_IY

http://www.youtube.com/watch?v=T28nfZimW2s

http://www.youtube.com/watch?v=vutlSmZwDjo

[Satamax]

A HP is a HP in the metric world ;D

http://en.wikipedia.org/wiki/Horsepower

Tho, i remember stories of american cars being highly overestimated on HP, due to the pre 72 SAE calc, and i should admit 70's peugeot and Renault were the same, being optimistic. Which might be the case with any auto maker. And may be that is still the case for small petrol or diesel engine makers, which don't have much rules to comply with as far as regulations for emissions are met.

Three phase squirrel cage motors in turn are all the same i'd think, and they have torque. As a rule of thumb, over here, we say one HP electric per 10cm (4") of cutting edge or diameter of blade.  Thought that doesn't work for bandsaws.

[stefan]

As i understand it one of the things when comparing different types of engines is that a gas or diesel engine only makes the power it is rated at, but, the electric motor when loaded draws more and more ampere and makes much more hp than it is rated at. To a point, of course, when it stalls.
If i remember correctly, the WM lt300 which is rated 30hp is said to make 60-70hp under max load.

Also i think it is recomended that a diesel engine should have roughly twice the hp vs. an electric on a sawmill.

[Al_Smith]

Although people like to argue the fact it's a general rule of thumb that electric as per HP rating equates to about double an internal combusion engine .

Just as one example of that if a person looked up the power requirements for hydaulic pumps on Surplus Center Hydraulics they give the rating as per electric motors .They have a foot note saying if using gasoline /diesel  double that rating .I didn't write that chart ,they did .

[bandmiller2]

One reason steam is such good power for a sawmill or locomotive is the reserve capacity in the boiler.You can pull 3 of 4 times the rated HP for a short time due to the energy stored in the boiler.When a saw is in the cut your drawing alot of HP the rest of the time the engine is loafing,that lets the boiler catch up. Frank C.

[Al_Smith]

Steam is a different breed of cat . I've seen 40 HP steamers out pull on a Baker fan what a diesel with twice the HP rating not be able to do .The harder they pull the more they exhaust steam up the stack the harder it draws the fire box .Under a big load while one might think the boiler pressure to decline it does just the opposite .

At Portland Indiana which has probabley the largest steam show in the midwest I saw a 40 HP Case steamer on an old Frick mill .36" plus oak and that old steamer never lost an rpm on the cut .By the same token a 830 JD diesel had a chore and they could not feed it quite as fast .Made  the JD bark pretty loud .

[rmack]

I think the original poster was asking about electric/diesel/gasoline relationship.

I'm not sure of the exact ratios but the relationship is something like

25hp electric = 35hp diesel = 45hp gas

again, those numbers are ballpark but I think that's the idea as far as comparing output.

If he's thinking about powering portable mill, steam probably isn't really an option. If it was, you could order an LT40 Super/Steamer  :D

[tyb525]

Horsepower is the same across the range of engines. It is the torque that makes the difference. Steam and electric have full torque basically through their whole rpm range.

Gas has the most torque at a certain rpm range only. Diesel has more torque at lower rpm's than gas, usually.

Horsepower is only a measure of how fast a certain amount of work is done. I.E. how fast the motor has to turn to do a certain amount of work.

A 10hp gas engine can do the same amount of work in the same time as an electric, but it would have to be spinning at ungodly high rpm's. Which is why 10hp electric seems much more powerful than gas, because the electric makes the torque at a much lower rpm.

[hackberry jake]

All motors are different. Ever seen those pop can motors they put on air compressors and planers and shop vacs? They're rated at 2-5 hp most of the time. I have a shop vac that says "8 horsepower" but only pulls 12 amps. I have  a 3 hp "real" motor on my RBI that would pull over 40 amps on 110 volt. Something is definately amiss

[Al_Smith]

 :D It's simple ,they lie about it .To be a true HP it has to draw at least 746 watts per HP .Unless they've somehow changed the laws of physics and didn't tell anybody .

[mikeb1079]

jake i've often chuckled about that phenomenon too.  it's all marketing and hype.  if you look close often they'll get a little creative when they describe the power ratings like "6.5 hp peak horsepower" or something like that.  luckily we're too smart to be taken in by such nonsense.   ;) :D ;)

[Al_Smith]

I think all that means is it will carry an overload for period of time before the smoke leaks out and it never runs again .

From my perspective on that I think the biggest prevaricators on that subject are Pacific rim motor manufacturers or vacuum cleaner salesmen .I would say the latter might in fact  tell bigger woopers than the former .

[tyb525]

I agree, with electric motors the amp's drawn is more important than the HP

[Al_Smith]

Actually amp draw is HP truth be known .

[bandmiller2]

ARHP [asian rim horse power] will leave you wanting,quess there horses are smaller than ours. Frank C.

[steamsawyer]

:D It's simple ,they lie about it .To be a true HP it has to draw at least 746 watts per HP .Unless they've somehow changed the laws of physics and didn't tell anybody .

Their little portable generators work the same way... 5500 watts peak, and 2500 continuous???  :D

[Al_Smith]

They are all guilty of handling the truth carelessly to some degree .

Take for example good old Briggs and Stratton . One year they call an oppossed twin cylinder an 18 HP .Couple years later the same exact engine is 19.5 .Same model number ,same displacement .The list is endless.