Another newbie question: fel and general work versus rpm

[murphy1244]

Last line says it all

 

[eyi]

Interesting responses indeed.

Thanks

 

[EMB5530]

This may be of no consequence as tractors are concerened but I know for a fact that RPM speed on an excavator has a direct impact on hydraulic strength. In some excavators you can have the engine RPM's at max and have less power then at a set specfic point. Although this is all I know. Is it because the overpressure has an electric adjustment that when said excavator is set at proper RPM allows for more pressure or is it a work of pump efficiency?
Don't know but maybe someone here will educate us all.

Oh yea, the machine I was in that I found this to be true was a Volvo EC220 I think.(as that may be of importance:anyone

 

[creekbend]

All the other TBN members have offered Sound Advice, so I won't attempt to add to their posts. I would like to suggest this addition to your FEL Bucket. The addition of a Tooth Bar will aid you in digging deeper or digging out rocks or stumps. Please remember that a Tractor isn't a dozer. Just a thought. Best wishes.

 

[MHarryE]

Every compact tractor I know uses direct acting relief valves in their loader circuits. Direct acting means the oil pressure acts against a spring. When the pressure is enough to lift the check off the seat, a bit of oil flows through. The pressure continues to build until the opening is enough to let all the oil flow through and that is where the loader stops lifting. Raise the engine rpm and the pump puts out more flow so the poppet must compress the spring more to allow the additional flow to bypass. Therefore the highest rpm will provide the maximum lifting force. Somewhere in my files I have charts of flow vs pressure characteristics of all the major relief valve suppliers but I don't have them available on my iPad or I could give you a graphic illustration. However you can see for yourself when you use your loader. I have Case, John Deere, New Holland, Caterpillar, Kubota and also older International equipment. They all work the same way.