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HYDRAULIC - THE LOGICAL WINCH POWER SOURCE
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The Milemarker H12 Hydraulic Winch...
... RELENTLESS PULLING POWER !
WHY HYDRAULIC?
There is no doubt that the low cost and ease of fitment make electric winches a popular choice. But they do have their limitations. A good quality winch should retrieve you and your vehicle when you get stuck. But what happens when you need longer and more regular periods of use or more power for more serious recovery work, professional and commercial use or serious winch challenge and competition use?
Attempting to improve the power or reliability of electric winches usually means spending large amounts of money on multi-battery systems with expensive control systems, all the time increasing water-sensitive complexity, which threatens reliability. The high operating speeds of electric motors and the consequent temperatures produced also compromise their lifespan when used at full capacity.
To illustrate this, a car battery is capable of providing high amounts of power for just a very few minutess, i.e. to crank an engine, or will provide low power levels for a much longer period, whilst being recharged from an alternator. Electric winches require extreme levels of power 150-600amps (2 - 6 kW). As you might realise, 6 kilowatts produces very high temperatures. These temperatures severly limit duty-cycles, the length of time which a motor can safely operate. Slow running hydraulic motors used on hydraulic winches don’t generate high temperatures. They provide enormous amounts of power for an indefinite period., that's why they are the norm in commercial and industrial applications. These slow running motors turn at around 25rpm, as opposed to electric winch motors that spin at 3,500-5,000rpm. Why the difference? The secret lies in the relative 'torque' or turning force that they each generate.
Torque versus Power - What’s the difference?
Electric motors are capable of producing high amounts of power, but the imporant figure is the torque rating. Torque (the turning force) rapidly drops off with electric motors as the load increases compared to hydraulic motor principles. This is due to the characteristics of the way they work.
Hydraulic motors are different, as the torque produced is constant. The power can be varied by the size of the pump, but the available torque figure never varies, it remains constant. The capability of any motor to turn a winch drum lies in the 'Torque' available, the 'Power' only varies the a rate at which it works.
With electric motors, the linear relationship between torque and speed is inversely proportional. It can be seen from the graph below that the torque figure for the electric motor decreases with rpm. Maximum power is halfway along the rpm vector. For every motor there is a specific Torque/Speed curve and Power curve.
SUDDENLY IT MAKES SENSE.
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There are some incidental advantages with hydraulic winches too.
Almost silent running.
Immediate stop when the switch is released, no running on.
No worries about flattening the battery.
Waterproofing. Hydraulic systems by definition have to be waterproof as the system cannot let fluid out, or air into the system. Milemarker hydraulic winches are actaully fully submersible, try that with an electric winch!
The System Choices
Described briefly below, have a look at the relevant category links for full details and prices for the 3 system types we offer.
Stage 1 - The H12 Power Steering Pump Powered System
The entry-level H12 system is driven by the vehicle's power steering pump. Although not fast, the no-load line speed in the high gear is 9 metres per minute and a loaded speed of around 1.5metres per minute. However, in a typical recovery scenario, this means only a few extra minutes of your time, which is no big deal when you consider the considerable reliability advantage. Plus you can still run your air-con, lights, wipers, heaters, and all the other electrical equipment while you are winching, and with confidence, which is more than you could do with a standard electric winch system.
If you are preparing a vehicle for remote-area expedition use reliability is everything, a mechanical failure in the UK can be sorted by calling out the AA. The same failure in the middle of the bush could be much more serious. So this system represents an excellent contingency measure for emergency or occasional but serious use.
Stage 2 - The H12 ZF74 Pump Powered System
Driven by the legendery quality of the German ZF hydraulic pump, for general off-road recovery use, this system offers unparalelled levels of relentless pulling power with a 10 feet/min line-speed even under full load. The genuine 4.7 tonne pull will get you out of anything, and completely out-perfoms electric winches.
Stage 3 - The H12 PTO (Power Take Off) System
The stage 3 system gets its power from a PTO (power take off) driven pump that attaches to the back of the LT230 transfer gearbox. With around110bhp now driving your winch rather than a 4-6hp electric motor the pulling power is phenominal. If you need almost unlimited pulling power for extreme off-roading or for commercial work then this is the system to choose. This system represents pulling potential not found among electric winches. It is also used as the driving force behind our famous Type R high-speed competition winch.
Stage 4 - The H12 Type R
for winch challenge use only
Before the development of the Type R the target line-speed was 100ft/min under load and 4.5tonne single line pull. "Type R" stands for rapid, which in comparison with electric winches is a gross understatement. With a line speed of 50 ft/min at 1000rpm, 100ft at 2000rpm and so on, how can it be compared to a battery driven winch?
Like other competition-challenge winches the H12 Type R has a big deep drum, which is crucial in preventing jamming, when the drum gets close to full and the winch is running fast.
Like any high-speed winches the Type R generates heat, but unlike an 'air-insulated' electric motor, it loses it through efficient radiation from constantly circulating fluid and an aluminium oil tank with a huge surface area to radiate the heat away.
We are currently building the content for our hydraulic winch web pages. But we do have some information on the relevant category links. In the meantime please call or email us for further details and prices.
The H12 Hydraulic Winch....... NOW YOU'RE WINCHING !
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