November 15, 20178 yr Question to those who have tested. When a 2 stages pump mentions 13 hp or 8 hp, does this necessarily require such an engine? On my press made from a log splitter I had a 2hp engine and the pump seems to be a truck power steering. I can not do the analogy of the specs of the pump but it is powerful and fast. Put a motor 2-3 hp on a pump that asks 5 hp will like effect? Slower flow? Thank you.
November 15, 20178 yr The pump just wont develop the design pressure and the smoke will quickly all leak out of the motor and it wont go any more
November 16, 20178 yr Author I found the specs of my pump, it's a 5 hp I was on the believe that a electric motor is stronger than a gas engine hp for hp... Anyway, I will stop doing my cheapstake and buy a 5 hp motor
November 17, 20178 yr Author Exactly, it's probably because of the torque of an electric motor is higher than I thought a 2-3 HP motor was equivalent to a 5 HP gas engine
November 19, 20178 yr On 2017/11/17 at 2:20 PM, blacksmith-450 said: Exactly, it's probably because of the torque of an electric motor is higher than I thought a 2-3 HP motor was equivalent to a 5 HP gas engine Here I agree with the logic! as we all "know" 100MPH is faster in a Porsche than in a Toyota! sorry it was too easy.
November 19, 20178 yr Why yes it is; that's why you are more likely to get a speeding ticket in a sports car than in a family car doing the same speed!
November 20, 20178 yr Electric motor HP rating is a thermal contraint based on a load needing that HP from the motor continuously at a temp of 40C ambient. Requesting more power from the motor for long periods will either burn it up or shorten it's life span. Gas engine horsepower is based on its maximum capability with no overlaod capability like electric has. See the difference? With such a characteristic you can spec an AC induction motor for lower horsepower in some specific applications because not only does the torque jump up in overload, but the speed change is very minimal, so you get more horsespower out of the motor when it's being overloaded. You can only do this for loads that do not require a constant HP over long periods. Like if a load is 5 HP at all times, then a 3 HP AC motor will burn up. You can only spec an AC motor with lower horsepower for periodical loads that will have rest periods in between the overload periods such that the motor's average temperature is the same of though the motor is ran at its full HP rating at all times. An example would be like log splitter since each piece of wood will need different levels of power, but you may occasionally run into a knot that will require more power beyond the motor's rating. Here is the conversion: 3 HPeletric = 5 HPgas 5 HPe = 8 HPg 7.5 HPe = 10 HPg 10 HPe = 15 HPg CONVERSION VALID ONLY FOR PERIODICAL LOADS!!!
November 21, 20178 yr Author Thank you very much Dennis for putting knowledge on simple impressions. Also I'm glad I'm not totally way-out !
November 22, 20178 yr One thing I forgot to add is DO NOT USE COMPRESSOR DUTY MOTORS unless you plan to do one for one conversion for gas engine replacement since they are peak rated!!!! Those motors are already factored into the load profile for compressors. They are NOT continuous rated at the power level they state. They will say a word phrase called "special" in the the run duty box instead of continuous. That is just a fancy term for peak power rating. So a 5 Hp compressor electric motor is the same as a true 3 HP electric motor or 5 HP gas engine. The price and weight of the motor also reflects this as you will often see that compressor duty motors are quite a bit cheaper and lighter in weight than the regular rated electric motors. Hope that helps!! Have a good thanksgiving!!!
February 21, 20224 yr On 11/15/2017 at 12:49 PM, BeaverNZ said: smoke will quickly all leak out of the motor Once the magic blue smoke leaves the motor it is a doorstop.
February 21, 20224 yr Close but not quite. Lots of Alaskans are frozen by magic smoke but it's usually passing. The ones that end up door stops can make it a permanent state if they stop the outside. Frozen exhaust is a problem in Fairbanks but it's mostly a prevailing inversion in the valley and modern autos don't crank out the exhaust smoke like the old days. Still, air quality can be a problem in winter. Frosty The Lucky.
February 21, 20224 yr Yes there is an inversion up the valley by Albuquerque so they are trying to ban wood stoves.
February 21, 20224 yr Air quality has always been poor in winter Fairbanks. EPA has been trying to clean it up since before I moved here and it's done a pretty good job. Unfortunately there's a faction that thinks it should be pristine and have managed to have the sales of new wood stoves seriously limited to high tech clean burning ones. Old types are grandfathered in so they get to stay. We have a Jotul multiple burn zone wood stove and once it warms up a little doesn't smoke at all. I stopped sweeping the stack because it doesn't get dirty at all. It was expensive though, around $6,500 14 years ago IIRC. Frosty The Lucky.
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