Hydraulic Competition winches

[Vit rich]

Hi all, im new to this forum but many of you may know me from Difflock.

Im looking at buying a milemaker hydraulic winch, and i have a few questions to go with this, iv had a search and whilst there are plenty of helpful topics they dont answer all my questions.

Im looking at using an upgraded 100CC motor, of almost exact spec to the type R. What bolt pattern and shaft size should i be looking for or are they universal?

For the pump, im looking at either a 78cc pump with a max cont pressure of 160 bar and a max pressure of 200 bar, or a 60cc pump but with a continuous pressure of 180 bar with a 230 bar max. The motor has a max continous pressure of 175 bar and a max intimittent of 200 bar. So would i be better off going with a larger pump displacement at a lower pressure or a small displacement with a higher pressure? What would be the advantages/disadvantages of going either way?

I also hear that thhe solenoids of the milemakers are pretty crappy, so im looking at a lever control valve to replace it. What should i be looking for? A two way lever to control forwards and revese? So it would just change the flow direction depending on which position i put the lever in?

The over center valve, am i correct in thisnking this acts like a brake on an electric winch? It will stop the car decending if i am holding it on the winch on a steep incline? Will this also allow me to go from stationary to lowering on a steep incline without having the intial drop as the system comes up to pressure again as it goes into revese? Can i get a lever controll valve with one of these valves built into it already? Will i need any other valves in there? Possibly an overload valve to stop the system over pressuring? If so what sort of pressure should i set this to as im guessing this will also stop me pulling to higher load with the winch by simply cutting it out? Does anyone have a diagram of how to set this whole system up?

What about pipe bores? What sort of size should i be looking at using? Im guessing smaller but thicker walled from the pump to valve to the motor and back, then thiner but larger for the resevoir to the pump and back?

I have pretty much decided to mount the pump direct via a UJ or similar to the crankshaft by moving the rad forwards slightly, this is being fitted to my project truck which has the body off atm so im trying to get everything fitted to the engine whilst it is nice and exposed.

Thanks for your time and patients with me, im new to hydraulics so im just trying to get my head around it all.

Thanks again and merry christmas

Rich

[Bush65]

Sorry I don't know type R motor specs.

These type of hydraulic motors are available as gerotor or geroller type. The geroller type has rollers that the rotor teeth run on. The rollers reduce frictional loss and allow higher loading, which translates to less power loss, higher allowable speed and pressure. They can also run slower.

The motors are available with different mounting flanges and shaft styles. You will need a 2 bolt flange (bolt centres 106.35 mm). The shaft required has straight sided splines. From memory it is 1" diameter and 6 splines - hopefully someone will confirm this.

Solenoids have an electrical coil and metal core that moves when current in the coil creates a magnetic field. I believe you are confusing the solenoid with the directional control valve that is operated by solenoids on the stock Milemarker winch. I don't know of problems with the solenoids (all solenoids get hot when energised for long periods and special solenoids are required for long energised periods), but the valves of a cheap design and only suitable for low flow rates (designed for use with a power steering pump). Their motor braking function is adequate for what was intended, but not for what you obviously want.

You will need to use a directional control valve suitable for the flow rate from your chosen pump. It is up to you whether the directional control is manual or solenoid operated.

I use a lever operated valve of the type used in mobile equipment. These have many different types of spools. For you application I recommend you get a spool that allows you to meter the flow with how much you move the lever.

The different spool port options affect flow and pressure drop with different flow directions. If you are intending to have a dual valve bank for front and rear winches, you have less options and will have to accept greater pressure drop.

You should get a valve that is spring return to centre.

You will need a pressure relief valve somewhere in the system. The lever operated valves used in mobile equipment can be supplied with a built in pressure relief valve. This will save space, hoses and fittings and make for a neater installation.

You should use an overcentre valve - you only need one for each winch (because the load can only pull rope from the winch in one direction).

Pipe/hose bore diameter is chosen to limit flow velocity. You need to know your pump flow rate, then the velocity can be calculated for pipe/hose bore. The recommended maximum velocity in pump suction lines is less than in pressure and return lines.

Edit: Regarding pump/motor size and pressure:

Consider the rated pressure for both the pump and motor. For the required rope pull, you can calculate the torque required at the winch drum, and then the torque required at the motor.

Then for the pressure and torque select the motor size.

Motor torque (Nm) = displacement (cm^3) x pressure (bar) / 62.8

or torque (lbf in) = disp (in^3) x pressure (psi) / 6.28

From required rope speed, determine drum speed then motor rotational speed (rpm).

Then Flow rate (l/min) = disp (cm^3) x rpm / 1000

or flow (gal/min) = disp (in^3) x rpm / 192

The required pump size (displacement) can be chosen for the flow rate and pump speed.

Edit 2. I'm not aware of any directional control valves with built in overcentre valves. Motors have optional port styles. You can get styles that suit mounting an overcentre valve directly on the motor. Remember if the overcentre valve is remote from the motor, braking will be lost if the pipe/hose between motor and valve fails.

An overcentre valve is used for braking and to control lowering. There are other valves that can be used for braking, but do not control lowering. You won't have any problems lowering if you use an overcentre valve that is adjusted (pressure setting) correctly.

[Vit rich]

Solenoids have an electrical coil and metal core that moves when current in the coil creates a magnetic field. I believe you are confusing the solenoid with the directional control valve that is operated by solenoids on the stock Milemarker winch. I don't know of problems with the solenoids (all solenoids get hot when energised for long periods and special solenoids are required for long energised periods), but the valves of a cheap design and only suitable for low flow rates (designed for use with a power steering pump). Their motor braking function is adequate for what was intended, but not for what you obviously want.

You will need to use a directional control valve suitable for the flow rate from your chosen pump. It is up to you whether the directional control is manual or solenoid operated.

I use a lever operated valve of the type used in mobile equipment. These have many different types of spools. For you application I recommend you get a spool that allows you to meter the flow with how much you move the lever.

The different spool port options affect flow and pressure drop with different flow directions. If you are intending to have a dual valve bank for front and rear winches, you have less options and will have to accept greater pressure drop.

You should get a valve that is spring return to centre.

This is the sort of thing i was looking at;

http://cgi.ebay.co.uk/BUCHER-HYDRAULIC-1-BANK-LEVER-VALVE-100-L-MIN-3-4_W0QQitemZ310188714106QQcmdZViewItemQQptZLH_DefaultDomain_3?hash=item4838b0287a

Mainly because the cheaper valves can only handel 45lpm, and the max flow of the motor im looking at is 60lpm. Sound reasonable?

Oh and im only using Hydraulic on the front, im using a Goodwinch TDS on the back with a bow 2 motor and 24v turbo unit.

You will need a pressure relief valve somewhere in the system. The lever operated valves used in mobile equipment can be supplied with a built in pressure relief valve. This will save space, hoses and fittings and make for a neater installation.

Im assuming thats what the 'main relief valve' on the valve i am looking at above is? How do i know where to set this? At the max pressure of the system?

I have read that whilst the main job of the relief valve is to stop the system bursting if a malfunction occures, it is also used to set the max pulling force of the winch, in that once the load becomes to hig, the pressure in the system becomes too large and the valve trips, but how is it possible to set this to be the case? By calculating the pressure of the system whilst the winch is at maximum pull? How would i go about doing this?

You should use an overcentre valve - you only need one for each winch (because the load can only pull rope from the winch in one direction).

Where abouts should this be located? Between the output of the directional controll valve and the motor?

Consider the rated pressure for both the pump and motor. For the required rope pull, you can calculate the torque required at the winch drum, and then the torque required at the motor.

Then for the pressure and torque select the motor size.

Motor torque (Nm) = displacement (cm^3) x pressure (bar) / 62.8

or torque (lbf in) = disp (in^3) x pressure (psi) / 6.28

From required rope speed, determine drum speed then motor rotational speed (rpm).

Then Flow rate (l/min) = disp (cm^3) x rpm / 1000

or flow (gal/min) = disp (in^3) x rpm / 192

The required pump size (displacement) can be chosen for the flow rate and pump speed.

Ok, the motor im looking at is;

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=310177906347&ssPageName=STRK:MEWAX:IT

Mated with either this pump;

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=320414356719&ssPageName=STRK:MEWAX:IT

Or this one.

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=320414367456&ssPageName=STRK:MEWAX:IT

Your formula confuse me slightly in that i carnt quite understand what i need to work out to make my selection. I know that pump 1 has a smaller displacement per stroke, but at a higher pressure, wereas pump 2 has a larger dispalcement, but at a lower pressure.

I would say im looking for speed over power, its only to pull out a sub 1.5tonne suzuki based truck, so aslong as i can get 9 - 10,000lb pull from it in low gear im happy, anything other than than will be wasted.

Thanks for all your help so far, as someone very wise once said, a little knowledge is a dangerous thing!

Rich

[Boothy]

Welcome to the forum.

I suggest you PM Saley, he's on this forum, he manafactures and competes with his own designed hydraulic competition winches, which are superb and very reasonably priced.

He's the man.

[Bush65]

This is the sort of thing i was looking at;

http://cgi.ebay.co.uk/BUCHER-HYDRAULIC-1-BANK-LEVER-VALVE-100-L-MIN-3-4_W0QQitemZ310188714106QQcmdZViewItemQQptZLH_DefaultDomain_3?hash=item4838b0287a

Mainly because the cheaper valves can only handel 45lpm, and the max flow of the motor im looking at is 60lpm. Sound reasonable?

Oh and im only using Hydraulic on the front, im using a Goodwinch TDS on the back with a bow 2 motor and 24v turbo unit.

You will need a pressure relief valve somewhere in the system. The lever operated valves used in mobile equipment can be supplied with a built in pressure relief valve. This will save space, hoses and fittings and make for a neater installation.

Im assuming thats what the 'main relief valve' on the valve i am looking at above is? How do i know where to set this? At the max pressure of the system?

I have read that whilst the main job of the relief valve is to stop the system bursting if a malfunction occures, it is also used to set the max pulling force of the winch, in that once the load becomes to hig, the pressure in the system becomes too large and the valve trips, but how is it possible to set this to be the case? By calculating the pressure of the system whilst the winch is at maximum pull? How would i go about doing this?

You should use an overcentre valve - you only need one for each winch (because the load can only pull rope from the winch in one direction).

Where abouts should this be located? Between the output of the directional controll valve and the motor?

Consider the rated pressure for both the pump and motor. For the required rope pull, you can calculate the torque required at the winch drum, and then the torque required at the motor.

Then for the pressure and torque select the motor size.

Motor torque (Nm) = displacement (cm^3) x pressure (bar) / 62.8

or torque (lbf in) = disp (in^3) x pressure (psi) / 6.28

From required rope speed, determine drum speed then motor rotational speed (rpm).

Then Flow rate (l/min) = disp (cm^3) x rpm / 1000

or flow (gal/min) = disp (in^3) x rpm / 192

The required pump size (displacement) can be chosen for the flow rate and pump speed.

Ok, the motor im looking at is;

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=310177906347&ssPageName=STRK:MEWAX:IT

Mated with either this pump;

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=320414356719&ssPageName=STRK:MEWAX:IT

Or this one.

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=320414367456&ssPageName=STRK:MEWAX:IT

Your formula confuse me slightly in that i carnt quite understand what i need to work out to make my selection. I know that pump 1 has a smaller displacement per stroke, but at a higher pressure, wereas pump 2 has a larger dispalcement, but at a lower pressure.

I would say im looking for speed over power, its only to pull out a sub 1.5tonne suzuki based truck, so aslong as i can get 9 - 10,000lb pull from it in low gear im happy, anything other than than will be wasted.

Thanks for all your help so far, as someone very wise once said, a little knowledge is a dangerous thing!

Rich

I don't know that particular manufacturer of the directional control valve.

The specifications look like they would be ok since you only want to use one hydraulic winch (it has an open centre spool which will not work if you have 2). Unfortunately not much information is given for spool options/details - perhaps the manufacturer has a web site with more info.

It is best IMHO, to have a spool with Vee notches so you have better speed control using the hand lever. As this is relatively common requirement with mobile equipment it may have them.

The relief valve in the valve body will do what you want. The adjustment for the relief valve can be seen on the right hand end of the valve body. The large silver hex section will be a relief valve cartridge that screws into a port on the valve housing. The smaller hexagon part is either a cover over the pressure adjustment screw, or the actual adjustment screw.

One way to set the relief valve pressure is to, hose the valve up to the pump ('P' pressure line) and tank ('T' return line), screw a pressure gauge into either of the motor ('A' or 'B') ports and plug the other. Back off the relief valve (screw out) then start up the pump and use the lever to select the output port that has the pressure gauge on it. The reading of the gauge will then be the setting that the relief valve is open and diverting all flow to tank. Screw in the relief valve adjustment until you have the required pressure reading. You will hear the fluid spilling through the relief valve and the load coming up on your engine as the pressure increases.

While the flow is going through the relief valve the power from the engine is going into heating the oil (by forcing it through the restriction in the relief valve). So you don't want to be doing this for too long and you need to watch your oil temperature.

Also you don't want to set the relief valve higher than necessary for the reason of heating the oil and for the overload protection of rope and attachments.

I can't tell from the information what type of relief valve it is or how fast it reacts. I assume it will be a direct acting (not compound) type. Direct acting relief valves are quicker acting than compound, but put more heat into the oil. For safety when winching, the quicker acting the relief valve the better - imagine if you have some slack rope while winching up a steep incline and the vehicle slips back and shock loads the rope. The quick acting relief valve will open to relieve the pressure spike (if the valve is not set too high) and soften the shock on your rope, winch and attachments.

You will need to calculate the pressure setting vs rope pull. After setting it try the winch with what you expect will impose your highest load on the winch rope. You may not hear the relief valve spilling flow to tank if you are running the engine hard but you may notice the winch slow as the load increases so the system pressure cracks the relief valve open. The winch will stall when the load exceeds the setting of the relief valve. If the setting is too low, the screw the relief setting in a little.

A relief valve doesn't trip. They crack open when the pressure overcomes the spring holding the poppet closed, and open further as pressure increases - more force (pressure times area of poppet) is needed to compress the spring further and open the port to allow greater flow. The pressure rise (above cracking pressure) is less for compound relief valves than direct acting relief valves.

Some people use a pressure gauge permanently connected. This is good for knowing what is going on, but I strongly caution against it because it is bad practice to have hydraulic lines in the vehicle cab. If you get a leak, the high pressure fluid is easily capable of puncturing your body - at best you may loose one of your legs, at worst you could loose your life. This stuff must be take very seriously. With my hydraulic winch system I use a pressure transducer that sends an electrical signal to an indicator - more expensive and not as accurate as a pressure gauge, but much safer.

The overcentre valve goes in the line between the directional control valve and the motor. Usually both of your lines will connect to the body of the overcentre valve, but it is important that the overcentre valve is in the line that is flow into the motor when winding in. The valve will have an internal 'pilot' passage from the other line (this is why they are both connected to the body).

An overcentre valve contains several components, a non return valve and a pilot operated relief valve. What makes them special is the pilot section of the relief valve is not supplied by the line that the valve is in but from a remote line. Pressurising the pilot line causes the relief valve to open regardless of the pressure on the relief poppet.

The overcentre valve has to be adjusted to a pressure that will hold your vehicle when the winch is stopped but under maximum. It allows free flow (through a non return valve) into the motor when you are winding in. It blocks the flow in the opposite direction so the rope can not be pulled off. A pressure relief valve section in the valve body will open allowing rope to pull off if the load is higher than the setting of the relief valve. When you move the lever of the directional control valve to wind out, the pressure in the line is connected to the 'pilot' section of the overcentre valve and opens the relief valve, allowing fluid to flow out of the motor - effectively releasing the brake. If it starts to run away while winding out, the pressure will drop in the 'pilot' line and the relief valve will close to hold the load.

There are different overcentre valves with different 'pilot ratios'. The numerical values will vary between manufactures, so I can't say use x.x pilot ratio. You should speak to your supplier and explain what you want to do, so they can supply a valve with the most suitable pilot ratio available.

With pumps the manufacturers pressure rating is not a pressure that the pump will produce, it is the system pressure that should not be exceeded (this also applies to the motor and may not be the same as the pump). The system pressure is produced by the load on the winch motor - at this stage forget about the pump.

Your choice of motor displacement determines what the system pressure will be. I gave you a formulae relating pressure, motor displacement and motor torque.

Motor torque (Nm) = displacement (cm^3) x pressure (bar) / 62.8

If you work from rope pull times winch drum radius (or more precisely radius to rope layer) will give you torque at the winch drum. Divide by the gear ratio (6 from memory but best to check) will give motor torque. As there are friction losses the actual torque will need to be increased (say multiply by 1.1 should be conservative enough).

Now you have torque, transform the formula to obtain pressure

Pressure (bar) = Torque (Nm) x 62.8 / displacement (cm^3)

If this pressure is low compared to the rating for the pump and motor, try a smaller displacement motor as it will wind faster for the same fluid flow. If the pressure is higher than the pump or motor rating, then you will need a higher displacement motor.

Remember that there will be pressure drop across your direction control valve and the overcentre valve, so the pressure will be higher at the pump and pressure relief valve in the control valve body, than at the motor.

[Vit rich]

Thats brilliant, thanks John.

One last question i now have.

You stated that the relief valve will create heat as the fluid passes through it. How can i get around this then?

A clutch on the pump to disengauge when not in use? Or another valve i can used after the pump to return oil back to the tank withoud causing excess heat build up?

Thanks again

Rich

[Vit rich]

Using your equations it would appear i have done somthing wrong or this motor isnt upto the job.

Ok, first of il calculate the max pull of the system with that motor fitted.

So, Max Motor torque 24.2DaNm x 6 (Gearbox) = 145.2 DaNm or 1452 NM

1452Nm = 12850 Inch Pounds

12850/1.75 (Winch drum radius, can anyone comfirm this? I read it had a diameter of 2.5")

= 7342.85 Lb of pull, which isnt enough!

Is it my maths thats wrong or one of the figures i have used?

Thanks

Rich

[Bush65]

Thats brilliant, thanks John.

One last question i now have.

You stated that the relief valve will create heat as the fluid passes through it. How can i get around this then?

A clutch on the pump to disengauge when not in use? Or another valve i can used after the pump to return oil back to the tank withoud causing excess heat build up?

Thanks again

Rich

While you are adjusting the relief valve setting all of the flow is going through the relief valve. Don't run the pump at high rpm (to reduce the flow rate) while making the adjustment and don't hold the lever in the direction required to see the pressure that the relief valve is operating at for longer than necessary.

When the control valve returns to neutral, the flow is from the pressure port to tank and the pressure drop (thus heat generated) is low.

In normal use the relief valve should not open. Unless the load is higher than intended for some reason, then the relief valve does it's job, which is to protect the rest of the system. It does this by converting the shock/excess/damaging energy to heat energy.

It is natural for the oil to heat up because it is doing work. The amount of work is pressure times flow. The oil reservoir capacity and ability to dissipate heat should be designed for the expected heating. Reservoir volume can be increased so it takes more heat to raise the oil temperature to unacceptable levels. The reservoir can be designed tall/long and narrow to maximise the surface area of the sides, which increases heat transfer out of the reservoir and reduces the distance for heat to travel from the oil in the centre of the reservoir to the sides.

If the above passive means of controlling oil temperature aren't practical or sufficient, an oil cooler will be required. Some people have used 200/300Tdi intercoolers for additional oil storage capacity and cooling - they are not the most efficient oil coolers, but if you have one that you don't have another use for, then it may be all you need (it all depends how much hard winching you are going to do and how much time is available for cooling between winch use).

Only run the pump when it is needed for winching - otherwise you are wasting engine power, which is just heating the oil.

[Bush65]

Using your equations it would appear i have done somthing wrong or this motor isnt upto the job.

Ok, first of il calculate the max pull of the system with that motor fitted.

So, Max Motor torque 24.2DaNm x 6 (Gearbox) = 145.2 DaNm or 1452 NM

1452Nm = 12850 Inch Pounds

12850/1.75 (Winch drum radius, can anyone comfirm this? I read it had a diameter of 2.5")

= 7342.85 Lb of pull, which isnt enough!

Is it my maths thats wrong or one of the figures i have used?

Thanks

Rich

I have just now checked some Milemarker information.

The difference between the 9000, 10500 and 12000 lb rated winches seems to be the motor displacement i.e. 14 in^3 (229 cc), 17.5 in^3 (293 cc), 19.5 in^3 (319 cc). They all have 6:1 gear reduction (low speed).

Their tabulated performance results are all given for a flow rate of 3.5 US gal/min or 13.25 litre/min and system operating pressure of 1500 psi or 103.4 bar.

Now I assume their performance results have taken friction losses (bearings and gears etc.) into account they should be realistic. Never the less they are a good check against your calculations.

Because you are planning to use a different displacement motor, you should divide the Milemarker line pull values by their motor displacement than multiply that by your selected motor displacement (making sure you use same displacement units for both motors - either both in inches cubed or both in cm cubed).

Then because you are planning to use a different system pressure, divide the new line pull by the Milemarker pressure, then multiply by your system pressure (either both pressures in psi or both in bar).

Similarly to determine line speed, multiply the given line speed by the Milemarker motor displacement, then divide by your motor displacement. Then divide the new value by the Milemarker flow rate, then multiply by your flow rate.

Take for example the Milemarker 9000 lb winch with 229 cc motor operating with 13.25 l/min at 103.4 bar.

Now if you use a 100 cc motor with 60 l/min at 160 bar (use your numbers here in place of these values), then for line pull:

Divide by 229 cc, multiply by 100 cc, then divide by 103.4 bar and multiply by 160 bar. This gives a line pull conversion factor of:

(100 x 160) / (229 x 103.4) = 0.676

Then convert all of the line pull values given for the Milemarker 9000 lb winch by multiplying them by our conversion factor of 0.676.

As you can see the line pull with the smaller displacement motor is considerably less than the standard winch. You need to increase the motor displacement, system pressure or both if you need more line pull.

The Milemarker given line pull values in lbf for the 9000 lb winch on layers 1, 2, 3 & 4 are:

9000, 7300, 6200 & 5400

These convert to 6084, 4935, 4191 & 3650 lbf.

For line speed, you will multiply by 229 cc, divide by 100 cc, then divide by 13.25 l/min and multiply by 60 l/min. This gives a line speed conversion factor of:

(229 cc x 60 l/min) / (100 cc x 13.25 l/min) = 10.37

Then convert all of the line speed values given for the Milemarker 9000 lb winch by multiplying them by our conversion factor of 10.37.

The Milemarker given line speed values in feet/min for the 9000 lb winch on layers 1, 2, 3 & 4 are:

6.16, 7.48, 8.8 & 10.5

These convert to 63.88, 77.57, 91.26 & 108.88 feet/min.

The Milemarker has a 2.5" (63.5 mm) diameter drum so you radius of 1.25" is correct, but you need the radius to the centre of the rope on the particular layer. So add half the rope diameter to the drum radius for the 1st rope layer. Then add rope diameter for successive rope layers.

Edit: The use of the previous formulae and procedures given are correct, the above takes advantage of published data as a check or short cut.

[carl hurst]

Welcome to the forum.

I suggest you PM Saley, he's on this forum, he manafactures and competes with his own designed hydraulic competition winches, which are superb and very reasonably priced.

He's the man.

As the man says,

Save your money and get one of these, you wont regret it,plus john (saley) will advise and even supply you all the kit you need, tried and tested system that works and no complcated math needed,

I was involved in the prototype's and these where born becouse the milemarker was not up to competition standards in any form,

They are the best hydraulic competition winch you can get, period.

Carl.

[Forcierer]

I suggest you PM Saley, he's on this forum, he manafactures and competes with his own designed hydraulic competition winches, which are superb and very reasonably priced.

He's the man.

I tried so. No response. Is Saley still active in this forum?

[yella 90]

I tried so. No response. Is Saley still active in this forum?

he's spending most of his time in the workshop at the mo trying to get his new toy ready for the xtc

[Milemarker Type S]

I have to agree that the Saley winch is a cracking bit of kit- though my Milemarker is none to shy now...

[steve b]

Thats fairly quick ! I take it you have upgraded your pump to a cat 2 crank driven ?

What sort of flow at the pump , 60litres/min?

Cheers

Steveb

[Milemarker Type S]

Yes- I finally did what i have been banging on about for years! It is a direct drive 26cc/rev group 2 pump- no chains or belts!! It just sits on an engine mounted cradle with a rubber coupling and dog clutch- leaving about 30mm clearance from the radiator. Flow wise (ignoring losses) I should get 65 l/min at 2500rpm which is the max quoted for the pump. I don't have a rev counter at the moment but even revving hard there was no cavitation at the pump.

The system needs a few tweeks- and I need to learn how to use it to best effect.

[pitmole]

Er last time I checked half of 2.5 was 1.25!

[portal pete]

Hi Rich

what engine will you be running? 60cc+ is way to big and you wont be able to power it unless you've got some serious hp. On the mitsimog we run a 32cc pump belt driven of the crank geared down 1.7:1. With the saley winch and type R 100cc motor this works very well. The typr R 100cc moter has a max 750rpm, if you were to use a 32cc pump direct driven you could only rev to 2000rpm before reaching the maximum motor rpm.

Rob

[Bush65]

Er last time I checked half of 2.5 was 1.25!

Thanks - I didn't check that very well

Since I can't go back and edit my earlier post to correct it, I have tried here (below)- correction in colour red.

Using your equations it would appear i have done somthing wrong or this motor isnt upto the job.

Ok, first of il calculate the max pull of the system with that motor fitted.

So, Max Motor torque 24.2DaNm x 6 (Gearbox) = 145.2 DaNm or 1452 NM

1452Nm = 12850 Inch Pounds

12850/1.75 (Winch drum radius, can anyone comfirm this? I read it had a diameter of 2.5")

= 7342.85 Lb of pull, which isnt enough!

Is it my maths thats wrong or one of the figures i have used?

Thanks

Rich

...

The Milemarker has a 2.5" (63.5 mm) diameter drum so you radius of 1.75" is correct should be 1.25", but you need the radius to the centre of the rope on the particular layer. So add half the rope diameter to the drum radius for the 1st rope layer. Then add rope diameter for successive rope layers.

...

[Milemarker Type S]

What pressure are you running your system at Rob?

I currently have my PRV set to 180 bar (2600 psi) with a 100cc/rev EPRM motor (which should give 25 DaMn at this pressure) and the winch definitely feels like it is not pulling as hard as it used to when I ran the standard Milemarker motor at 120 bar. The above calcs with the correct 1.25 (0.5 x 2.5 inches) suggests it should be pulling 10620 lbs (4.6 Tons) at the first layer...

[portal pete]

What pressure are you running your system at Rob?

I currently have my PRV set to 180 bar (2600 psi) with a 100cc/rev EPRM motor (which should give 25 DaMn at this pressure) and the winch definitely feels like it is not pulling as hard as it used to when I ran the standard Milemarker motor at 120 bar. The above calcs with the correct 1.25 (0.5 x 2.5 inches) suggests it should be pulling 10620 lbs (4.6 Tons) at the first layer...

Its set at 210bar, my drums are 450mm wide so always pulling on the lower layers which helps. Will your system take any more pressure?

Rob

[Milemarker Type S]

Hi Rob- thanks for the response. The the limiting factor at the moment is the pump- It is only rated at 180bar for intermittent use, hence the current prv setting, and 190 peak- I intend to wind it the prv up to 190 bar and see how I get on. I would think that the pump ratings given would have to be slightly conservative to allow for a reasonable service life in continous use?- anyone know what is most likley to happen if the peak pressure is exceeded??

If it is still not pulling hard enough I will have to source a higher pressure group 2 pump- motor can handle up to 225 bar peak. I take it you are running a group 3 pump?- I did not have enough room for a group 3 clutch and pump unfortunately...

The other option is to use a 125cc MPRM motor which gives higher torque but would obviously loose some of the speed- not the preferred option.

Also can anyone confirm my calculated 4.6 ton pull at the drum?

[Bush65]

Hi Rob- thanks for the response. The the limiting factor at the moment is the pump- It is only rated at 180bar for intermittent use, hence the current prv setting, and 190 peak- I intend to wind it the prv up to 190 bar and see how I get on. I would think that the pump ratings given would have to be slightly conservative to allow for a reasonable service life in continous use?- anyone know what is most likley to happen if the peak pressure is exceeded??

If it is still not pulling hard enough I will have to source a higher pressure group 2 pump- motor can handle up to 225 bar peak. I take it you are running a group 3 pump?- I did not have enough room for a group 3 clutch and pump unfortunately...

The other option is to use a 125cc MPRM motor which gives higher torque but would obviously loose some of the speed- not the preferred option.

Also can anyone confirm my calculated 4.6 ton pull at the drum?

My pump a Parker Gresen CP16-100C-23-S has a displacement of 32.1 cc/rev, max speed 3300 rpm and max pressure 3000 psi (207 bar). Delivery is approx 60 l/min at 1900 rpm, 75 l/min at 2350 rpm, 95 l/min at 3000 rpm, 106 l/min at 3300 rpm.

The Group 2 and Group 3 classification is no very universal, and I have not been able to find what is specified, and so I have no idea where my pump fits in this scheme.

A 100 cc/rev motor at 180 bar, produces a theoretical (assuming no friction loss) torque of:

Tmotor = 100 cc/rev x 180 bar / 62.8 = 286.6 Nm

Taking Milemarker gear reduction as 6:1, then theoretical (assuming no friction loss) torque of:

Tdrum = Tmotor x 6 i.e. 286.6 x 6 = 1719.7 Nm

Taking drum diameter as 63 mm, and rope diameter as 10mm, give radius of 1st layer of rope as:

R1 = (63 mm + 10 mm) / 2 = 36.5 mm

Then rope pull Prope is Tdrum / R1 i.e. Prope = 1719.7 Nm / 36.5 mm = 47.11 kN

Now 47.11 Kn /9.81 m/s^2 = 4802 kg or 4.8 tonne.

If you take frictional losses in motor and winch into account, then I think your 4.6 tonne rope pull is still optimistic. Probably 4.5 tonne is more likely.

[Milemarker Type S]

Excellent- thank you John- much appreciated. So winding the system pressure up to 190 bar would give me a theoretical 5 ton pull on the first layer of rope.

Though you now lead me to some confusion as to why it felt like my winch was not pulling that hard on Saturday???- The pump was definitely making the 180 bar pressure- I have a gauge in the cab and could hear the prv in the valve opening. Either the pulls were simply harder than I thought or something else is wrong somewhere?- the only thing I can think of is the overcentre valve which is fitted direct to the motor (It is a dual one- yes I know I only needed a single one!!)- I have never adjusted it from the setting it came with- could this be causing an issue? If so what do I adjust it to?

Si

[Bush65]

There will be pressure drop across the overcentre valve, i.e. the pressure at the valve outlet/motor inlet will be lower than the pressure at the valve inlet. How much pressure drop will depend on the valve design/manufacture. It also is a function of fluid flow rate, and would be greater if the actual flow rate is close to the rated flow for the valve. Overcentre valves have a range of pilot ratio, which is selected for the intended use. Pressure drop might change with different pilot ratio for some designs/manufacturers. It is possible that a dual overcentre valve would have a higher pressure drop, because of more complex internal flow paths.

I doubt pressure drop will be affected by the valve pressure setting.

The overcentre valve should be adjusted so that it will hold the maximum expected load when winching stops. I.e. not open to allow flow from the winch motor under the maximum expected rope load. I see no advantage in setting the valve excessively high.

Sorry I can't be more specific as these things are dependent on the actual overcentre valve used, the pilot ratio, load, etc.

[Bush65]

What pressure are you running your system at Rob?

I currently have my PRV set to 180 bar (2600 psi) with a 100cc/rev EPRM motor (which should give 25 DaMn at this pressure) and the winch definitely feels like it is not pulling as hard as it used to when I ran the standard Milemarker motor at 120 bar. The above calcs with the correct 1.25 (0.5 x 2.5 inches) suggests it should be pulling 10620 lbs (4.6 Tons) at the first layer...

Comparing expected rope pull with different motor displacement and system pressure combination is a relatively simple exercise.

I don't know what size motor was standard on your Milemarker winch.

The 10500 lb, Milemarker I have came with a Danfoss DH315 motor. This motor has a displacement of 306 cc/min.

Say we want to know what pressure to use with a 100 cc/min motor to achieve the same rope pull as a 300 cc/min motor at 90 bar. We know rope pull is proportional to motor torque, and motor torque is proportional to displacement x pressure.

Now we want new motor torque to equal old motor torque.

Then P new x disp new = P old x disp old

i.e. Pnew = Pold x disold / dispnew

i.e. Pnew = 90 x 300 / 100

therefore Pnew = 270 bar

What this shows is if the new motor is 1/3 the displacement of the old, then the pressure needs to be 3 times as much. If the new motor was 1/2, the pressure required would be 2 times.