|
|
Winch Essentials
Of all the different properties of a given winch, the line pull
rating is the most important. It is the maximum static load the winch
can exert on the cable. This will be achieved on the first wrap of the
cable on the drum. For every successive wrap of cable on the drum the
winch's torque decreases 12%. This must be taken into account when
selecting a winch for your 4X4.
The line pull, line speed, and current draw (applicable only to an
Electric Winch; a Hydraulic winch does not have this problem) indicates
when a weight of X lbs is pulled, it will be pulled at Y ft/min using Z
amps. These numbers vary widely from winch to winch. They should be an
important consideration in a winch purchase. It is best to ask an
experienced winch owner to determine what is best for you.
Weight is an indicator of the constuction of the winch. Winches must
be very STRONG. Too little weight means too little metal used in the
construction. Too much weight could mean that your front end will sag. A
benefit of the Hydraulic winch is that it does weigh less.
| Q. How do I select a winch for my truck? |
| A. The most important thing to consider when selecting
a winch is whether it is capable of pulling 1.5 times the gross
vehicle weight (GVW) of your vehicle (don't forget to take into
account that 12% drop in pulling power for every extra wrap of
cable on the drum - a 9000lb winch has a line pull of approx.
7000lbs on the third wrap). GVW is the real world weight of your
vehicle, i.e. fully loaded. So fill up your gas tank, load up all
those off-road goodies, tools, hi-lift jacks, people and go get
your vehicle weighed. |
| Q. What do the different winch gear systems mean and what
difference will they make when I'm operating them? |
| A. There are three common gearing systems, worm gear,
spur gear and planetary gear. They all do the same job, gear down
the high speed motor to a low speed high torque winch drum. The
gear reduction ratio is by how much the motor's output revolutions
are reduced for the spindle. The greater the reduction, the more
revolutions the motor has to turn for one spindle revolution and
the less the motor has to work for that revolution. The difference
in the gearing systems is mainly in their transfer efficiency.
The worm gear has a transfer effiency of 35-40%. This causes
the winch to be self-braking even under heavy loads, but this
means the unit will need a clutch mechanism for free spooling.
Worm gears offer the most reduction, very high reliability,
built-in braking mechnism, and generally a slower winching speed.
The spur and planetary gear systems have efficiencies of 75%
and 65% respectively. This means they have a tendency to free
spool when loaded, therefore a braking mechanism is needed.
Planatary gears are the most common and provide both strength and
smooth operation with good resistance to torque loads. |
| Q. I've noticed while looking through the manufacturer's
catalogs that there are different types of electric motors. What
is the difference between series wound motors and permanent magnet
motors? Is one better than the other? |
| A. An electric motor basically has two major parts, the
stator and the rotor (or armature). It is the job of the stator to
produce a magnetic field which will cause the rotor to rotate when
an electric current flows through it.
In a permanent magnet motor, the stator uses permanent magnets.
This means the current drain on the battery is lower than series
wound motors (which uses field coils in the stator). Permanent
magnet motors are good for light and medium duty winches, but
winching time and load has to be carefully monitored as they tend
to overheat. Series wound motors are used in heavier duty winches,
but tend to cost more. |
| Q. Will my electrical system cope with the extra load of an
electrical winch? |
| A. For most pulls, yes. There a lot of people out there
with one battery, stock alternator, and a winch. Keep in mind
though that running a winch is the equivalent to moving your truck
on the starter motor, there is a tremendous draw. Most electric
winches draw around 400 amps at full load which is far more than
even a high output alternator will produce. Stock alternators
typically produce 40-90 amps at peak output and the battery will
keep up for only so long. Because of this, many people install
high output alternators and dual battery systems to support an
electric winch.
When shopping for a high output alternators, remember to
consider alternator output at idle, these figures can differ
wildly, especially on older models. Regardless of what alternator
you have, it is a good idea to keep up the RPMs while you are
winching if possible. Most alternators have peak outputs near
cruising RPMS. Also, keep you truck running after winching to give
your battery time to recover.
Upgrading the battery or going to a dual battery system is also
a good idea. The more cold cranking amps your battery (or
batteries) produces, the longer you can pull without your engine
running. An electronic battery management system is also a good
idea to issolate the batteries.
After you have got power to the winch you will need to get it
back to the battery. Ensure your grounding system is capable and
all connections are clean, this is where most systems waste power.
The best grounding systems will use large diameter cables (such as
welding cables), the battery negative post connects to the engine
block, the alternator ground connects to the engine (usually
through its case) and then the frame is connected to the engine
using a grounding strap. The best bet is to connect the a ground
directly from the winch to the battery. |
| Q. I want to be able to winch from either the front or the
back of my truck, are the receiver mounted winches any good?
|
| A. Receiver mounted winches are very useful, but
remember their static pull load is limited by the receiver they
fit into. For a class III hitch that is 5000lbs. Because of this,
receiver mounted winches are not really suitable for full sized
trucks. |
| Q. When I buy my winch, what comes with it, and what else
do I need to start using it? |
| A. Most winches come with nothing, but some places do a
deal which includes the remote cable control and fairlead hawser.
You will also need the mounting kit for your vehicle. I strongly
recommend you buy the winch manufacturers kit. It has been
designed for that winch and vehicle with all safety aspects
considered. Home made winch mounts are disasters looking for a
place to happen.
Your winch will now work, but it is limited to straight line
pulls between two vehicles. The addition of the following items
will greatly increase your winch's usefulness - Tree saver straps
(never wrap a cable directly round a tree, you will kill the tree
and kink your cable), a couple of clevis pins, snatch blocks, a
choke chain and of course thick leather gloves.
Attach tow hooks to the frame on all four corners of your
vehicle. |
| Q. What safety equipment will I need? |
| A. You just need your leather gloves and common sense.
Never handle the cable with bare hands, a frayed cable can cut
skin to the bone. The most common winch accident is getting your
fingers caught in the cable as the last of it winds onto the drum.
Always use the remote control cable when winching, and keep every
one out of range of the cable . |
| Q. What other safety considerations are there? |
| A. Be aware that a broken winch cable can have enough
force in its whiplash to cut through a truck's roof and
windshield. Imagine what would happen if the cable met a person. A
cable that hits a small tree will tear the tree down. A cable that
hits a large tree can wrap tightly around a tree so a person
behind the tree is not necessarily safe. Solid objects such as
hooks and snatch blocks will fly through anything, including a
truck's hood, if a cable breaks. People should stand well out of
range of the cable and never in line with the cable. Furthermore,
if a cable breaks, the truck being winched may roll downhill, so
never stand downhill of any vehicle being winched. |
| Q. Is it common to break a winch cable? Should I carry a
spare? |
| A. No to both questions. A properly maintained cable is
very reliable (see question about maintenance) and carrying a
spare will only increase the risk of damaging it. Winch cable is
aircraft grade cable and has a breaking strain of 32,000lbs - much
higher than the capacity of the winch.
It is much more common for for snatch blocks and anchor points
to break because they were poorly rigged up. It is a good idea to
drape a heavy cloth jacket over the cable to limit the whiplash if
something snaps. If someone has to steer the vehicle being
winched, then raise the hood for extra protection. Ensure all
anchor points are firm. |
| Q. Is my winch maintenance free? |
| A. Although many people seem to think the answer to
this one is yes, the answer is really no! I have met a number of
people in the mountains stuck, with a winch that won't work. A
little care and preventative maintenance would have ensured its
reliability.
Your winch should be maintained on a regular basis. Lubricate
all required points, inspect all mounts, pulleys, straps and
clevis pins, check they are not damaged, or showing signs of
fatigue, and are free of moisture. Inspect your remote control
lead and electrical system for damage and chaffed insulation. Make
sure all terminals are corrosion free and tight. After each trip
unspool the cable. Check for kinks and frayed strands (damaged
cables should be replaced). Lubricate cable with a chain and cable
lubricant (normal grease will collect dirt) and wind back onto
drum. |
| Q. What does using a snatch block achieve? |
| A. Basically it doubles your available pulling power
(in fact it's an increase of 85% after safety considerations). It
will also allow you to perform pulls at an angle to your truck.
People are rarely considerate enough to get stuck straight in
front of you. |
| Q. When I double up the winch line using the snatch block,
where should I attach the return line. |
| A. If the snatch block is attached to another vehicle,
which you are trying to free, then the return line should be
connected to a third vehicle or tree, to spread the load.
If the snatch block is anchored to a tree and you are trying to
free yourself, then the return line should be hooked onto your
vehicle's frame. DO NOT hook it back on to the winch mount as this
will effectively double the load on the mounting plate. |
| Q. What is the best way of anchoring my vehicle when I'm
trying to winch another vehicle out of trouble? |
| A. Anchor your vehicle to another vehicle or any other
fixed object using your tow strap, tree saver, choker chain etc.
The one thing to remember is attach the anchor strap to your
vehicle at the same end as your winch, otherwise you may stretch
your vehicle's frame. Often, simply hitting the brakes will be
sufficient to hold your vehicle in place. |
Electric vs. Hydraulic vs. PTO
Just when everyone thought the electric vs. PTO winch war was over,
along comes the hydraulic winch. There are still pockets of resistence,
but generally, electric winches have won out over the PTO winch. Enter
the hydraulic winches and another set of advantages and disadvantages.
The PTO (Power Take Off) winch is driven by a small drive shaft that
is driven by a PTO adapter that bolts to the transmission or transfer
case. Only certain transmissions and transfer cases have PTO ports (e.g.
T-18, SM-465, Dana 18, ...). Most electric and hydraulic winches have
only one speed, but with a transfer case PTO port, shifting gears can be
used to change line speed, torque, and direction. Transmission PTO ports
drive off the counter shaft, so they work in one direction and have one
speed that can be varied by engine RPM. Since engine power drives the
PTO winch, your engine must be working to operate a PTO winch. This is
probably the biggest disadvantage of the PTO winch since your engine
isn't likely to be running for long when your truck is upside down or
under water in a raging river. Not long enough to run out the cable
anyway.
The electric winch does not require the engine to be running to work,
which is it's biggest advantage. The big argument against the electric
winch in the past was it would drain you battery and there was no way
your alternator could provide sufficient power for a long pull. The
automotive industry has made great improvements in alternator and
battery technology over the past years which has given the advantage to
the electric winch. Batteries have more power and alternators have
higher outputs. An electric winch might even work if your truck
is upsidedown or under water.
Some of the advantages of the hydraulic winch are pulling power, pull
duration, and weight. The hydraulic winch runs off your existing power
steering pump. There is no need to upgrade alternator of battery for the
winch, but you may consider upgrading your power steering pump. If you
don't have power steering, convert now, regardless of what winch you
get. A hydraulic winch should be able to pull harder and longer than a
electric winch with out over heating. Hydraulic winches are also much
lighter than electric winches, putting less strain on your front axle
and front springs.
Hydraulic winches suffer from the same disadvantage as the PTO winch,
neither works when the engine isn't running. The hydraulic winches I've
seen have a real slow line speed, this could an advantage under some
circumstances, but generally this is a disadvantage. There is a two
speed model, but the high speed is not for use under load. Another
disadvantage I've heard from people with hydraulic winches is the
reduced ability to steer and winch at the same time.
ContributorsSome of the information on this page was originally
prepared by Steve Williams in June 1993 as part of the Off-Road Mailing
list FAQ. Some text has been modified and added by Terry Howe and others
no doubt. |