Purchased a CAT 312 Rega a few months ago and got into a conversation with a guy that has a lot more experience than me with excavator's about the operating speed I was using. On the scale of 1-10 I was running the machine at 6-7 most of the time, thinking the machine was doing what I wanted and I wasn't stalling the machine with the work I was doing. He stated I should be running the machine at full power all the time or I would burn out the pump. Doesn't seem right to me. If I'm not continully loading the pump to the max why would I need to run the machine wide open. Anyway, I don't have a lot of hours on excavators and would like some advice. Thanks in advance for your comments. CW
We had a fair bit of discussion in regard to skid steers here: and most of that is relavent. I have to tell you, IMHO the "burn out the pump" business is a load of crap.....otherwise there would be tens of thousands of excavators all over the world with "burn out" pumps. A concrete contractor I work with regularly has a 312. He builds concrete retaining walls and does all difficult concrete pilings etc. The machines has about 7000 hrs and he runs it at 80%. I've looked over a number of manuals and not been able to find anything that says you must run at 100%. I run my mini at 100% when digging because it clocks a lot of hours idling and low speeds.
Welcome to HEF Bugle1! :drinkup
I am always looking for a definite answer on this, & it seems everyone has their own ideas, but I was running a little Terramite ( made here in West Virginia) today & on the hoe was warning label saying to set the throttle at half throttle when using the backhoe. The machine had a Perkins diesel. Each machine is different I am sure, but it may be that the manufacturers want them ran at full throttle so the user has the best impression possible of the machines capabilities.
faster rpm water pump etc circulate more oil and water through coolers. Fan runs faster. But also if the pump is a say fixed displacment pump (not variable), your running lots of oil over the bypass if yoru not working it hard/fast, and creating a lot of heat as well by running full throttle vs half
i run full throttle and in the fastest user/work mode i can all the time. Don't see any reason why i would want to work slower :beatsme
I don't run it at full throttle either but its running at 95% throttle but as Tyler said run it at the fastest setting you can get. Faster the hydraulics move smoother you can be. Most machines now have auto revs where the machine revs up automatically when you start using the controls. I'am not sure how good that is either but it seems to work. I ran three machines a old Hitachi a Komatsu and a Deere the Deere had the hydraulics turned down or something was wrong with it. Using the Deere drove me whacky it was slow. You get used to things moving at a certain speed to work. Well I was used to a fast machine so it took alot to try do things slower.
With the computer controlled load sensing machines with variable displacement pumps it doesn't matter where you set the throttle. Basically the computer senses the speed of the engine and adjusts the output of the pump to keep from drawing engine speed down. Say you want to pick up the boom and the throttle is set so the engine is turning at 1,000 RPM. In old machines that used positive displacement pumps the engine RPM might drop 200 to 400 RPM. If there was a load in the bucket the engine might even stall. With today's machines the computer knows the engine is running at 1,000 and as soon as it starts to dip the computer changes the output of the pump and slows down the flow so it will pick up the boom. That is also how the mode systems work. Each setting has a set engine speed and a specific flow characteristic from the pump to suit the operator for a specified operation. So run the machine anyway you want. You can't hurt it!
When doing digging or trenching, I am at full throttle. When moving spoilage, loading trucks or moving stone, I am at 90% throttle.
what are your personal reasons for slowing the machine down for certian jobs? i see it as these machines are made to move dirt, and that extra 200 rpm makes a big difference in your speed. When loading trucks, or moving material if you can get 5 cycles per minute instead of 4 that adds up in a hurry, hundreds of yards in a day. unless you are on a t&m job i dont see the benifit
Been gone for a few days. Thanks for all the replies. I'm not a contractor. Don't have any of what I would consider hard digging. Just a little logging, stump burning and ditching on my own place. I would guess I'm running it at 2/3 throttle most of the time and it seems to do all I want smoothly. Seems like the consensus is that I'm not gonna hurt anything runing it at that speed. So thats what I'll continue to do. Thanks again. CW
I don't run at less than 80% throttle, ever. If I'm trenching or hogging dirt I run the machine full bore. You won't burn up the pump by running at lower RPMs, but lugging a diesel is something I don't do.
Pyrometer, anyone????
Most of our work involves working around lines. I usually dig at 80-90% throttle, but when I know lines are near, I back it down. If I hit a line, it usually bogs the machine down enough that it will not harm the line.
What kind of a digger do you have that will bog down if you hit a 3/4" plastic gas line?
A properly set up hydraulic excavator will not "lug" or bog down the engine....it will go slower...it might stop, but the hydraulics will not overload the engine...it will only do with what power is available. Older machines or dozers, graders, loader...different story.
Here ya go. Run it just above idle...
Ya know, I saw one of those a while back. After searchin for a half hour I threw it down and walked off. I could not find the master switch.:beatsme
Thats because you don't have your Phd ointhead
Hummm...Shovel..DOT....no comment..
Excavator speed If it was hard on an excavator pump when not run at full throttle, Why does Hitachi and John Deere have different Modes and engines speed built into the machines standard?? Cat has this feature as an option on some machines. If running a machine at less than full speed was right I know of many machines that should not be running. It is just another old wives tale.
i set all throttle controls on my excavators on R&R..."rock/n/roll
I really don't notice too much of a difference b/n the 2 settings. I can load a truck just as quick on both settings. I do it for fuel consumption. Does it work ??? I have no idea. I guess that it is just my personal preference.
most excavators have three modes light mem high this changes the rpm setting from low med high when u see that guy again tell him when he is slewing his machine to count the nuber of times he slews around tell him if he go's to many times he will twist the hoses that go to the travell motors and tyey will break cheerse gotta go my pet kangaroo has ran of goto catch him
i dunno, i run a hoe all out all the time, if it couldnt stand up to something made like that from the factory, why would they put "10" on there??
First of all, this has been a main topic of mine for many years now. I have been running hoes for 26 years (just to get the experience out of the equasion) I DONT EVER run less than full throttle EVER and yes I am always digging around utilities both plasic and steel it is my firm belief the machine runs smoother and is most controllable at full throttle. at full throttle, you dont have to fight the ground and the bucket pulls through much easier and you can feel see and sense through the levers for resistance. the only exception would be old air controlled bucyrus hoes (40 h and such)
I have never heard that one. I don't see how not running wide open all the time would hurt the machine. if that where the case they would only have one mode on machines instead of giving you a choice.
yeah what he said...i also think the machine is smoothest and easiest to control when wide open, and if you vary your speed all the time you cant get used to the reisistance in the levers at one certain speed....well said:cool2
I can tell i'm in the minority with this comment but i normally run at 7-8 range. I am not a 7-5 excavator operator, or make a living off of being an operator. i've own my 320 for 2+ yrs. taught myself, and tried to pickup tidbits of expertise from places like here. I have found the fuel consumption to be much less operating at a little less RPM. I will grant the machine runs slightly slower and yet in my own case i find it to be smoother operating and get just as much done.
i guess its just a personal preferance and machine behavior thing, if your machine is smooth and you can run it good on a lower rpm, then dig'er up. I just think that if you have it on 7 or 8 if you are trying to pull the stick in and go to lift the boom or curl the bucket it seems like it takes away alot more from one function than if you have it wide open and i think it swings a load a little smoother on full throttle, the only time i idle one down is puttin it on a trailer, i turn it all the way down to 1 so i dont jerk myself off the ramps. And as for fuel consumption the company buys fuel so i wouldn't know about that i dont keep track of it...all i know is if you dig the guts out of a 315 its still hard to run a whole tank out in a day. And also its a production kind of thing...run it wide open, use more fuel, but get the job done faster, i guess it depends on if you bid the job or doing it by the hr.