Problem-Solver, Series 7
A West Virginia mine required mine required a 14,000 foot belt conveyor system from a longwall face to the surface.
The customer wanted to utilize one continuous belt conveyor to eliminate all the transfer points
and to standardize on 150 horsepower motors. This meant it would require five motors to
power this particular conveyor.
Using one large drive on the head shaft would create too much belt tension,
thus the drives needed to be spaced out along the conveyor.
This multiple drive concept is called a booster conveyor. The boosters drive the main
conveyor belt by friction only. This concept is new to the U.S. coal industry and this is
one of the first installations in operation using fixed filled fluid couplings.
Because of the multiple drive configuration, our Rexnord distributor suggested using
True Torque
fluid couplings to ensure each drive would pull its intended share of the load.
Current Problems
As five separate drives were required to power the conveyor,
load sharing was very important.
Starting five drive motors across- the-line simultaneously can overload electrical load
centers and increase in-rush current to high levels.
As the longwall face moves towards
the mine entrance, the conveyor’s
power requirement drops. As the
conveyor shortens, one main drive
would be tremendously oversized.
The True Torque Solution
Falk fluid couplings can be easily balanced by adding or subtracting fluid from each coupling.
True Torque fluid couplings can be individually started because of the ability of each coupling to temporarily
operate at 100% slip. By starting one motor at a time, current draw and switchgear costs are lowered.
By employing the booster drive system equipped with Falk fluid couplings, the number of drives can be reduced
quickly as the power requirements dictate.
Implementation
The customer purchased five complete drives consisting of Falk 1110FC2 drives,
420HFD-20 fluid couplings with thermal trip switches, and 1130T10 Steelflex couplings for the low speed connection.
The fluid couplings were installed and started in sequence beginning with the head drives. The oil levels were adjusted
for each coupling to equalize loading based upon motor amperage draw.
All the drives work in unison and the user is very pleased with the simplicity and the clean, reliable performance.
Let us show you how to give your productivity a boost, by using True
Torque fluid couplings!
CONTACT YOUR REXNORD FLUID COUPLING DISTRIBUTOR FOR THE SOLUTIONS TO YOUR POWER TRANSMISSION PROBLEMS.
Form 860701
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