RE: (ET) DC hydraulic pumps [Virus checked]

["Dave Reuter" <david reuter iavinc com>]

Just a far out thought to those that are looking into putting hydraulics on
their Tractor. If your starting from scratch why not look into electric
ball screws or electric screw lifts. Put them in place of your hydraulic
cylinder. Nothing more needed but the wires and controls switches. Use a
nut & screw if you want it stay in position after a load is on it and the
power is off. Or use  a ball nut & screw if you just want a lot of lifting
power. Ball nut is more efficient but since there is minimal friction it
will not stay in place unless you keep the electric load on the motor. When
power is off it will want to back drive the motor with a load. If you use a
screw nut then the friction in the nut (if designed right) will stay in
place until you power screw in the reverse direction to lower your load.

I have used both in automotive applications before and was able to generate
about 3000 lbs force from a single screw nut 12v system which held against
its load when power was off.

Dave Reuter


----- Forwarded by Dave Reuter/IAVINC/IAV on 05/12/2003 09:16 AM -----
                                                                           
                                                                    
                      "Pieter Litchfield"                                  
                                                                    
                      <plitch attglobal net>           To:       "harry 
landis" <hlandis hotmail com>, <elec-trak cosmos phy tufts edu>        
                      Sent by:                         cc:                 
                                                                    
                      owner-elec-trak cosmos ph        Subject:  RE: (ET) 
DC hydraulic pumps                                                   
                      y.tufts.edu                                          
                                                                    
                                                                           
                                                                    
                                                                           
                                                                    
                      05/10/2003 10:02 AM                                  
                                                                    
                                                                           
                                                                    
                                                                           
                                                                    




My ET has a bucket loader, and the pump for it is a conventional single
stage hydraulic pump mounted on a bracket and coupled with a rubber and
metal assembly to a 36 volt motor.  It has worked well for over 30 years.
If a 36 volt motor can be found, the other parts are readily available
(new)
from places like Northern Tool.    See thie web site.  A new pump is about
$90, a coupling $7, a mounting bracket about $30.  The first bid on the
used
pump below was about $150.  When bidding remember the alternative is $120
plus the cost of a new or used 36 volt motor.  I would think a trip to the
local hydraulic repair shop and gold cart dealer would get you a used pump,
mount and motor for a dollar amount under the opening bid on a very used
looking fork lift system.  Of course, you would still need a resevior,
filter, fittings, hoses, valves, and cylinders.

As a design suggestion (given here before), I'd suggest looking into the
possiblility of making the pump run only when the controls are actuated
(like an electric/hydraulic pickup truck plow) rather than on a constant
basis with valved flow of oil (like my tractor).  A constantly running pump
heats the oil (by compression and friction) and shortens battery run time
significantly.  I wonder if, in fact, a 12 volt hydraulic/electric plow
lift
could be retrofitted with a 36 volt motor?  It would be a great package for
ET lifts that require both lift and dump circuits (two seperate functions)
since the old h/e plow I used on my pickup had angle and lift circuits (two
seperate functions).  Hmmm.....



-----Original Message-----
From: owner-elec-trak cosmos phy tufts edu
[mailto:owner-elec-trak cosmos phy tufts edu]On Behalf Of harry landis
Sent: Friday, May 09, 2003 10:46 PM
To: elec-trak cosmos phy tufts edu
Subject: (ET) DC hydraulic pumps



I mentioned a while ago that there was available a 2 HP 36/48 VDC motor
driven hydraulic pump available. Actually it turns out that it is about 1
hp, and there are also two other 24 VDC pumps available also. And it is
possible that there may be more similar stuff showing up, like some 24VDC
7.5 HP hydraulic pumps, and some heavy duty relays, etc. I got a friend who
is better equipped to store and ship such things to put them on ebay. They
came out of some perfectly good electric forklifts that a big warehouse
decided to get rid of. Some companies appear to have way too much money and
way too little brains.
The URLs are:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2530085643&category=11770

&rd=1

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2530098281&category=11770

&rd=1

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2530098801

Also, I got a GE EV100 SCR controller. It looks like it controls a bunch of
high powered contactors to run a forklift. Is it a ET or EV useful thing?

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