Right angle electric drive head: This is an older generation Griffin
product. The brake capacity of this model is too small to handle most modern PC pump installations.
Right angle gas powered drive head: This is an example of the Corod GBF 5.0 series
drive head driven straight off the crank shaft of a gas motor. The motor in this case is powered by well
bore gas that is slightly processed by the green cylinder to the right. This type of installation is popular
in regions were there is no electric power or is considered a temporary condition until
electric power is installed at the well site.
Electric/hydraulic drive head site: This site photo shows the sometimes extraordinary
measures taken to make a well operational. The shed (with external fuel tank) houses an electric
generator, which generates power to turn a hydraulic pump, which ultimately operates a hydraulic motor to
turn the polished rod.
Electric/hydraulic drive head: A typical electric/hydraulic skid package (this one
is by BMW). Used because of the ability to vary the speed of the drive head, provide good torque limiting, and
excellent recoil control. Even though this type of configuration is inefficient in the fact that power is
converted many times before actually operating the well, the benefits still sometimes justify it's use.
Vertical electric drive head: A very popular configuration that is capable of meeting
most requirements. It is a simpler, lower cost solution than the right angle gear drive configuration,
with the primary drawback being the lack of high ratio drive. Producing a polished rod speed of less than
150~200 rpm becomes a problem with the vertical electric drive head. Also direct drive from a gas motor
(like the examples shown above) is impossible.
Gearbox/belt electric drive head: Grenco Inc. being the primary manufacturer of this
type of drive head. Unlike the previously mentioned right angle gear drives that utilize a ring and pinion
arrangement, this drive uses gears in the same plane. The primary advantage is the compact size and high
reduction ratio's achievable with multiple reduction stages. It is a very popular drive head with heavy oil
producers because of its low speed ability (less than 50rpm).