mmmmmdonuts 274 #1 Posted March 16, 2017 I am looking to buy a hydraulic gear pump for a project I am working on and I want to double check what the rotation I need to buy. Specifically the engine is a Kohler Command Pro CH621/CH18 and the pump will be mounted through an electric PTO on the PTO shaft side. I believe the PTO shaft spins CCW? So therefore the pump I would need to buy would be CW? Is that correct? The pump will most likely be mounted using a yoke or a lovejoy coupler. Thank you. 1 Share this post Link to post Share on other sites
wallfish 15,935 #2 Posted March 16, 2017 Your assumptions are correct but I'm curious about how the "yoke or lovejoy" coupler is connected to an electric PTO. Belt to a jack shaft? How about a description of the project? 1 Share this post Link to post Share on other sites
gwest_ca-(File Mod) 10,503 #3 Posted March 16, 2017 You will need to verify how the pump manufacturers determine the direction of rotation. Looking at the end of the pump shaft or the back of the pump? Another consideration Some pump shafts run on a bearing and that allows them to withstand the side load of a drive belt. Others have no bearings and need to be driven by a lovejoy coupler. If you have ever had to wrap a rope around a starter hub to pull start an engine the hub is always on the flywheel side of the engine. The pulled rope turns the flywheel clockwise - that's how I remember the crankshaft direction. So the pto side is turning CCW. Garry 3 Share this post Link to post Share on other sites
rmaynard 14,909 #4 Posted March 16, 2017 Get yourself a pump that is bi-directional, then you won't have to worry about which way is correct. 3 Share this post Link to post Share on other sites
wallfish 15,935 #5 Posted March 16, 2017 CW or CCW -- Belt or direct couple This should solve all those questions except volume required. http://www.northerntool.com/shop/tools/product_200329712_200329712 Good for small tractor stuff but may be a little slow for big stuff like a 5 inch log splitter cylinder. 2 Share this post Link to post Share on other sites
mmmmmdonuts 274 #6 Posted March 16, 2017 (edited) Yes it is a belt to a spline shaft (1 inch 15T) for a front PTO that runs at 2000 RPM. I keep looking at that pump from northern tool (and it currently backordered ) but since at WOT it is only slightly above 4gpm I don't know if my cycle times are going to be too slow especially if I operated 3/4 to full throttle range. The hydraulics are 4 (2x16x1.125 cyclinders) two for the boom and two for the bucket. Using the 2 cylinders each at 2GPM because they are operating together I calculate a cycle time of 10.8 seconds (6.4 extend and 4.8 retract). I was looking at different loader manuals with cycle times and this seems a tad slow but I could be wrong. This was the pump I was looking at http://www.surpluscenter.com/Hydraulics/Hydraulic-Pumps/Gear-Pumps/0-73-cu-in-DYNAMIC-GPF2012PC-HYD-PUMP-9-7790-B.axd This should provide me a cycle time of 7.4 (4.4 extend and 3 second retract) **ADDED IN EDIT BELOW ** Sorry for the double post but I think this one would work better possibly and it is bi-directional although it would be slightly slower than what I linked above. http://www.northerntool.com/shop/tools/product_200641992_200641992 Just trying to figure cycle times to shoot for. Edited March 16, 2017 by mmmmmdonuts 1 Share this post Link to post Share on other sites
Ed Kennell 35,829 #7 Posted March 16, 2017 (edited) Garry has it correct again. All shafts turn CW and CCW....just depends which end you're looking at. Reminds me of a new $50,000 model reversible pump/turbine runner I tested many years ago for the Raccoon Mt. Hydro Project. After much head scratching over the very low efficiency, It was discovered to be the wrong "hand". That was when we quit referring to turbine runners as left or right hand and went to CW/CCW always viewed from the motor/generator. I do still have a $50,000 5 axis milled hand polished aluminum bronze 90 lb boat anchor. The point is when someone says CW or CCW, make sure you and they know which end they are looking at. Edited March 16, 2017 by Ed Kennell 2 Share this post Link to post Share on other sites
elcamino/wheelhorse 9,060 #8 Posted March 16, 2017 @Ed Kennell How big is your dang boat? 90lb anchor would take two men and a boy to lift and toss over the side. 1 Share this post Link to post Share on other sites
JoeM 7,645 #9 Posted March 16, 2017 I've used both 4 gpm and 8 gpm pumps on loader builds. The 8 was to fast for me, okay if your just throwing dirt around but when I have fine work I have to almost idle. The 4 is slow but sure, but I would lean toward the 6 gpm unit if building another. Model# G1224C5A300N00. Not to much difference in speed using 1 1/2" or 2" cylinders. I did use #6 hoses with #4 JIC nuts on the hoses for the cylinders. #8 nut JIC on the pump. Share this post Link to post Share on other sites
wallfish 15,935 #10 Posted March 17, 2017 9 hours ago, mmmmmdonuts said: (6.4 extend and 4.8 retract). That seems like a long time when written down but unless you are scraping the ground and loading trucks all day, you rarely go full motion for long periods of time. It can be a real pain when it's too fast. BUT it is easier to slow it down with finesse of the spool valve levers or with a flow restrictor valve than it is to speed it up. 1 Share this post Link to post Share on other sites
mmmmmdonuts 274 #11 Posted March 17, 2017 Thank you for the help. I think I am going to try and size it for a little more than 6GPM and go from there. I completely forgot about a flow restrictor valve as a possibility so sizing it up and having the option to slow it down is great. Share this post Link to post Share on other sites
JoeM 7,645 #12 Posted March 18, 2017 Other consideration is if your using a hydro transmission. I spin up the RPM to 3000 to keep the hydro running good and cool. The flow restrictor will work, but keep in mind, your using a positive displacement gear pump. The excess oil is going to be dumping across the relief, can make a lot of heat in a small system. Share this post Link to post Share on other sites
mmmmmdonuts 274 #13 Posted March 19, 2017 I ended up ordering this pump. http://www.northerntool.com/shop/tools/product_200641992_200641992 It is bi-directional and like OILUJ52 said, I plan on operating the tractor somewhere between 3000-3600RPM because it is a hydro with an Eaton 11 transmission. With that pump listed at full throttle the PTO will be spinning at roughly 2000RPM and the pump will be outputting approximately 6.06GPM. At 3000RPM on the engine, the PTO is at 1667RPM outputting approximately 5.05GPM. Thank you for all the help. Share this post Link to post Share on other sites