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motor selection for power hammer

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Hello everyone.

Ive started to build a power hammer for sword making. I have a base made of 3 layers. One is 3/4inchwood, then a layer of thick rubber and 15mm steel sheet on top of that, this is to take the shock out of the hammer. The main beam is 8 inch boz iron bolted to the floor. I want to have an 100lb hammer but I only have a 1hp 1475 rpm single phase motor. I want to know if this motor is powerful enough to lift the hammer weight and if not what size of motor would be needed. I am also using a tire clutch. The motor also needs to move the hammer at a good speed.

 

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Get your self a beverage of your choice a comfortable chair and research this section . All of what you want to know is all ready posted by someone. 

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I agree with the previous post about conducting research - but I can say that a 1hp motor is probably too small.  I have a 3hp, 1750 RPM motor driving a jackshaft on a 100lb Beaudry hammer and it's not oversized - I would not want to use anything smaller.

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You cut your coat to fit your cloth---down size the weight or go buy another motor,  Will the hammer have a baseplate on top of that measly 15mm plate?

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One thing about the motor is that it is an older motor and very large and heavy. I read somewhere on this forum that have more power than what the nameplate says.

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I want a pickup truck with the power of a Freightliner but the fuel economy of a VW Jetta diesel. Can you recommend a model?

Here is a chart which takes into account old motors, because it was written when they were new;

 

http://www.littlegianthammer.com/resources/Useful Information.pdf

1 hp will power a 25lb hammer. 

You could maybe go 35 lb but you are already starting to compromise. 

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Horse power is a measurement of work done, 1 Hp= 1Hp no matter what some youtube video may say to the contrary about theirs being bigger, multi phase, or other nonsense.  sorry.

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That may be the case in the world of electric motors, Steve. In the world of gas and desiel the morketing guys have jaked us all up, shaft, breke etc. a 4 horse steam tractor has a heck of a lot more "grunt" than a 40 horse desiel tractor. 

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A bit of reserch to remind me of the facts, a metric horsepower (the original messure is 735.5 watts, a mechanical horsepower Is 745.7 watts, wile modern electric mottors are rated at 746 watts, 

so if the original is 33,000 ft#a min is equal to 735.5 watts or one horsepower.

automotive horsepower is to wonky to get into, as well as taxed horsepower and steam boiler horsepower (9,809.5 watts) 

locomotives and tractors used to be tested on the same test, draw bar, or how much/how fast could it acualy pull somthing, now tractors are operating off somthing else wonky like automotive shaft hirsepower

the question is, as in automotive testing, the method has changed both in the us,and europ several times, leading to as much as +/-10% deviation between tests and the same powerplant, how has the testing changed for electric motors in the last 125 years? 

Edited by Charles R. Stevens

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As I recall older motors don't magically generate more power for a given size (as Steve noted) but the generally larger mass of the windings found on big old motors are able to soak up more heat if abused.  That means they can be mistreated slightly more before the bad smelling smoke comes out and things get expensive.  Not much more, but perhaps that is where the misunderstanding came from.  

There is a lot of trade literature out there for comparing electric HP to internal combustion HP and it indicates that in the real world the two are not equal.  Gonna have to read up, alway wondered why my tractor had 2 HP ratings.  Shouldn't 50 hp in one spot be 50 hp in another?

 

Edited by Judson Yaggy

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I must have missed the part of him wanting to install a steam boiler and a V8 engine to the hammer. should I list water wheels too. It is possible tht since the octane was so low in early auto engines, its ratings were first set up for those 24 octane fuels/Cu In displacement formula, than as fuels got higher octane,  as in 87 to 95 octane available,   they never re calculated the  formulas for Hp ?

Edited by Steve Sells

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Never know! Lol. Sorry Steve the point I was trying to make is the "horsepower" is a widely abused unit of mesure, that infact was soon abandoned after its inseption, exept that it made for good marketing at the time, then because of marketing it has stuck!. Now adays (thanks for sending me down that rabit hole) electric motors are rated bu theoretical modles generated by compuers based of the desighn of the motor, i would assume a pre appollo electric motor would have been tested by phisical means as apposed to crazy sliderule computations. And as the automotive industry has changed how it tests and has lead to changes in the "output" of the same powerplant one would assume it may apply to electric motors as well. 

Interesting tid bit, Depart ment of energy sugjests fitting a motor so it runs at 3/4 of its rated output for max energy effencey (has some interesting tests you can perform to tell if your "over motored" dont know how that helps any of us tho...

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simply put:  today electric motors HP is calculated by the wattage used these days, very straight forward.

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Nope, calculated buy theroretical output, not imput, based on the desighn and therotical madnetic feilld strength. A 5 hp 3 phase brushless motor draws a lot less wattage (amps X voltage) than a single phase 1 hp (or god forbid a DC motor) this is why electric cars use 3 phase motors.

wow, a once in a decade event here, rare is it that you catch Steve, and on a simi electric question no less. i respect hou more now that I know your human, lol. 

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Nope, calculated buy theroretical output, not imput, based on the desighn and therotical madnetic feilld strength. A 5 hp 3 phase brushless motor draws a lot less wattage (amps X voltage) than a single phase 1 hp (or god forbid a DC motor) this is why electric cars use 3 phase motors.

wow, a once in a decade event here, rare is it that you catch Steve, and on a simi electric question no less. i respect hou more now that I know your human, lol. 

​Nah, you only think you caught him. 3 phase are also calculated by wattage as he said.

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wattage = ampres x voltage

3 phase has the voltage split 120 degrees and has 4 wires plus ground

single phase is split over 180 degrees and has 2 wires plus ground

Two phase is 90 degrees to confuse everyone and has 4 wires plus ground, only available in a  limited geographical area.

wattage is wattage,  there is no reason to confuse the issue,  If you really want,  I can repost the Hp calculations page from the National Electrical Code book, I am a licensed master electrician and its sitting right here on my desk.

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Gets a little confusing when you start describing mechanical energy in watts , not sure how you apply Ohm's law there. I have no doubt of your knowledge, no less your skill as an electrician. I would recommend you. I'd hire you (not so many trades men I would say that about) it's just that this is fuzzy, as this is a case of "watts" as a metric measurement describing energy, electric, heat, kinetic etc, and "watts" the standard measure of electrical energy. You just can't put the same amount of energy in one side of a machine and get the same out the other. A 1hp motor (745 wats out put) is going to use some energy, so if the I put Wattege is the same or less we are not talking about the same measure of energy. But that isn't my point, my point is that before the computers to make calculating theoretic out put the out put was physically messed, and like an old anvil, the weight stamp and the scale often don't agree. Wether that is to the pluss or the minus? Depends on the day it was built and shows finger was on the scale. Would I replace a 1 1/2 hp motor with a 1hp? No, I like safe bets, and short of an engineer and some fact tests I,m going with what works.

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I dont know but I have this Chop Saw advertised at 5.5 horse

http://www.congresstools.com/catalog/categories/

and this shop vac at 5hp in my shop

http://www.homedepot.com/p/RIDGID-12-gal-5-PHP-Wet-Dry-Vacuum-WD1270/202554972

I also have a 55lb stirker power hammer with a 5hp electric motor that  beats at about 240 hits per minute and the machine's total weight is about 2700 pounds

Should I be able to run that hammer on the shop vac or saw 5hp motors?????

 

I think this proves the point that horse power is all over the map. 

 

Edited by pike3e

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unless your machine needs at least a 40 amp line at 120 volts to work,  they are not 5 HP.  You wont get more than 2 Hp from a normal house outlet,  But have fun with your fantasy.  I give up.

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unless your machine needs a 40 amp line at 120 volts to work,  they are not 5 HP.  You wont get more than 2 Hp from a normal house outlet,  But have fun with your fantasy.  I give up.

​You tried.

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Na, Steve you always a wealth of information. Tho advertizing copy and manufactures "rating" for consumer products can be realy out their. 

The chop saw is advertised at 15 amps and 5.5 hp, ( 1800 watts Imput?) and the shop vac as 5 max hp (ith that when the smoke gets out?) i relise that industrial motors, those we talk were talking about for the hammer, have a continual operation rating (the rating on the plate) and depending on the thpe of motor it has an over power rating, operating at more than rated output causes heat, heat eventualy melts the insulation ot pops the breaker. Most of us know that most electric motors will draw more electricity as the load (resistance to its ability to reach desighned RPM) so not only will an over loaded electric motor draw a lot more electricity under load, it will infact draw a lot as it starts up,'thats why many single phase motors have capasior starts. 

 

 

dont give up on us ignorant heathans,'Steve. We need you,'your the only voice of reason some of us have!

 

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Ok found some specta, acording to the electric mottor manufacuring assotiation type "B" motors are rated at 50-70% so a 1hp, 120v motor draws 10-13 a (1200-1560 watts) to produce 745 watts of mechanical out put. 

So both the chopsaw and the vacume are using some gues (max hp) as to how much you can overload theas mottors befor the factory smoke gets out (assuming it can draw enugh amps before circut breaker trips) as a marketing ploy.

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​You tried.

I should have gone into full load current calculations, and that states we would need 60 amp lines installed for proper power for 5 Hp, because of the 140% of the HP rating needed,  I was trying to explain the BS out there to actually help people understand what is needed,  but I should have known better, some people dont want to learn so why do I waste my time trying.  Its fine if you want to believe you have 5 Hp all you want, but do not complain here when it fails to operate your hammer.

Horsepower is not all over the map,  snake oils salesmen are all over the map when they are telling you this crap.

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