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When you look at fundamental differences in common electric
winches, a few important components and design characteristics stand
out. Of the differences in common winches, the motor and the gear train are the top two design
differences that will determine the quality and stamina for an intended use. The motor will vary in
motor type
and in the horsepower rating. The gear train will vary with different types of
gear systems, each with their own characteristics and benefits.
Both the motor and gear train work together resulting in the final
rating of an electric winch. Understanding these important
fundamentals will help you understand what winch you should buy
Motor Type
 Winches use two types of
DC motors, Permanent Magnet Motors and Series
Wound Motors.
All electric DC winch motors consist of one
set of coils, called an armature, inside another set of coils or a
set of permanent magnets, called the stator.
It is the job of the stator to produce a magnetic
field which will cause the rotor (or armature) to rotate when an
electric current flows through it.
Applying a voltage to the coils produces a torque in the armature,
resulting in motion. With all types of motors, the
higher the horsepower rating, the more toque and power the motor
will have. The winch rating is a combination of motor torque
and gear train gear ratio reduction. Motor horsepower has a
direct effect on both line speed & pulling power.
Permanent Magnet
Motors -
In a permanent magnet motor, the stator uses
permanent magnets and there are no field
coils.
With permanent magnet motors, the drain on
your battery tends to be less than series
wound motors, which uses field coils in the stator rather than
magnets. Permanent magnet motors are better suited for
light to medium duty winching because they tend to generate more
heat and overheat. Winching time &
load should be carefully monitored as they have the tendency to
overheat. The magnets in permanent magnet motors can loose
their field strength over time and repeated use.
Series Wound Motors - With
a series wound motor, the field coils are connected in series with the
armature coil. Series wound motors are powerful and efficient at high speed
and generate the most torque for a given current.
A series wound motor will
uses more current over a permanent magnet motor because they use
field coils to generate a magnetic field. Series wound
winches are heavier duty winches, and tend to be more expensive.
A permanent magnetic motor will pull the same as a series wound motor, at at
less of an amperage draw on the battery and charging system. However, as the
permanent magnet motor gets warmer, the
power will drop as the amperage draw will increase. The amperage draw on a series wound motor
will stay the same throughout the duty cycle.
Winch Ratings - Most winch ratings are generally limited by the maximum
amperage draw, with right around 400 being the cut-off point. Anymore than
that would most likely damage the power source or charging system. In
order to reduce the amperage usually the gear ratio will need to be increased
numerically, to relive the motor from the increasing stress, however, this will
also reduce the line speed at the same time.
Gear Train - Gear Systems and Spool Diameter
There are three common gearing systems,
planetary gear, worm gear, and spur gear. The job of the gear system
on all three types is to gear down the high speed motor
to a low speed, high torque output to turn the winch drum. The gear reduction ratio is 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.
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Planetary Gears - Planetary gears are the most common and
provide both strength and smooth operation with good
resistance to torque loads. The planetary gear systems
have efficiency 65% and have a tendency to free spool when
loaded, therefore a braking mechanism is needed.
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| Worm Gear - The worm gear has a transfer efficiency 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
mechanism, and generally a slower winching speed.
Worm drives are generally stronger and simpler than other
gear systems such as the planetary due to the lack of the need for a braking system as
well as the extreme gear reductions possible. The primary drawback of a
worm gear system is the
noticeable reduction in overall line speed, especially in a 'no load' cable
reel-up situation. Here, the planetary has an advantage.
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Spur Gear - The spur gear systems have efficiency
of 75% and like the planetary gear system, they have a tendency to free spool when loaded,
therefore a braking mechanism is needed. Only the WARN M8274 has a
spur gear due to its different design characteristics.
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Spool Diameter
The Drum diameter & Gear Ratio have a direct effect on
pulling power while affecting line speed at the same time. The width of the drum determines the inevitable loss of
pulling power as the cable spools in. As the layers on the drum increase, the
effective gear ratio drops reducing the pulling power. The narrower the drum, the quicker
the cable spools up and therefore, looses it's pulling power quicker as compared
to a wider drum.
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Typical Drum Layered Power Loss
12,000 lbs. Winch Example
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Layers Of Cable
Remaining on 3" Drum |
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Available
Pull Power |
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(Bare) 1 |
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12,000 lbs. |
| 2 |
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9,480 lbs. |
| 3 |
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7,800 lbs. |
| 4 |
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6,720 lbs. |
| 5 |
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5,760 lbs. |
| (Full) 6 |
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5,160 lbs. |
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 Winch Solenoid
What is the Solenoid?
Solenoids are electromagnetic switches. When electricity
is sent to the solenoid via the remote switch, a magnetic field forms
causing the circuit to the winch to complete and the winch motor to move
either forward or backward depending on which solenoids are activated.
Solenoid Mounting
Solenoid mounting can be a major
consideration. Winches can either have an
Integrated or Remote Solenoid pack. A remote solenoid is
externally mounted off of the winch. An integrated solenoid is
part of the winch either within a "bridge" over the cable
or mounted else where on the winch such as above the
motor. There
are benefits to both types of solenoid mounting options. With
space restrictions a remote solenoid can reduce the space require to
mount the winch itself while the solenoid can be mounted remotely
while an integrated solenoid offers
protection in a compact package.
2 or 4 Solenoids?
Some winches have two solenoids, and others have
four. Two solenoids configurations are typically found in permanent magnet motor
winches and are cheaper, less
powerful, heavier, less reliable.
Four solenoid configurations are typically found in series wound
winches and are stronger, lighter, more
reliable.
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