SolarAndWood said:
Gooserider said:
Northern may well be using the same part number, seeing as how they are getting the pump from Haldex, who probably hasn't changed the number either... The big advantage of a two-stage pump isn't so much saving electricity as it is allowing the use of a higher volume pump under low load conditions.
While I was running it yesterday, I thought it was a straight pump with that volume coming at pressure as I never heard the motor bog down or noticed that the cylinder slowed. In fact, when I stopped it and checked everything, the motor was the only thing still comfortable to touch. Definitely happy with the electric power.
On my machine, I definitely hear the engine load change as it hits a good round, but the cylinder rarely slows noticeably - what I've observed is that even tough rounds usually "pop" within less than an inch of wedge travel, and then the pressure drops back to very low as the wedge continues down to shear the remaining connecting fibers and spread the splits apart.
I have a 5" cylinder and a 16gpm, two stage pump - assuming all values are nominal, that means I am pumping 61.6 cubic inches/sec which is going to move my wedge at 3.1"/sec in high speed, and 15.4c"/sec at low speed for .78"/sec wedge speed - even if I kick into low speed for a fraction of a second, it is HARD to see the wedge change speed... I have a pressure guage on my machine, and what I've seen is that it splits most rounds at between 500 and 1,000 psi, and the tough rounds might go to 1500, it is RARE to go over that - but the pressure surge is for only a fraction of a second, and as soon as it is over the pressure goes back to about 2-300 PSI, which is about what it shows any time I'm moving the wedge. Considering that the switch to high pressure / low speed happens around 6-800 psi, I'm probably only spending a fraction of a second at the slower speed.
Watching the guage and wedge, essentially what happens is that when a heavy round is encountered, the wedge slows and the pressure starts building in a linear relationship until the round "pops" and then the wedge immediately speeds back up as the pressure drops down to the minimum needed to keep it moving.
Electrics don't generally have the same sound change that a gas engine does, but certainly it doesn't sound like my engine is working hard. I just get a slight tone change when I work the cycle lever, with occasionally an even slighter tone change if I hit a tough round.
Gooserider said:
For fluid temperature, I would say that if the pump is complaining, you are either WAY to hot, or you have a different problem that is being agravated by the fluid warming up...
Is this something I figure out with pressure gauges? Should I be adding one/more while I have it apart anyway?
You probably could figure it out with guages, but what I've seen suggested is to use an IR thermometer, you will see a hot spot where you are experiencing a pressure change that isn't doing work, which you want to address...
I have a pressure guage on the outlet side of my pump, but I didn't "need" it - I mostly added it because I wanted to add a couple inches to my hose length, and the easiest way to do so was to put in a "T" fitting, and add the guage... It is a nice to have, but more for the fun of it than because it tells me anything I didn't already know...
Gooserider
