Fluid Coupling Torque For Overlands
Originally Posted by Himanshu
Assume a trough belt conveyor is driven by a Constant Fill Fluid Coupling with 3 phase AC Induction motor. Is the torque supplied by this driving system to the driven conveyor system dependent on the load requirement of the conveyor (loaded conveyor / empty conveyor) ? How can the torque transmitted be formulated during static calculations of belt conveyor?
Thanks in advance......
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Unfortunately, you cannot make a simple paper and pencil calculation unless you only need the peak value.
The fluid coupling is a pump which transmits torque as a function of its relative speeds between impeller (drive input) and runner (reducer). Drive motor side (impeller) will typically come up to speed within about 2 seconds, while reducer (runner on conveyor belt side) will accelerate as a function of its resistance, coupling fill level and functional control of delay fill chamber into working circuit, coupling internal configuration (mfg. differences and model differences), fluid temperature and viscosity properties,.... There are formulae that describe this phenomena, which utilize the secretive Lambda performance curve (torque vs. speed or slip rpm).
There are methods to extract this information from physical testing, which is quite complicated.
In a nutshell, there is simple calculation method I am aware of, having designed many hundreds with fluid couplings, measured coupling actions in the field and at various mfg. factories, including large failures created by fluid couplings. ■
Correction - Fluid Coupling Calculation Vs Conveyor Acceelrati…
The last sentence of my reply has a bad typo:
"In a nutshell, there is simple calculation method" should read "In a nutshell, there is NO simple calculation method"
Sorry. ■
Another Point Missed- Fluid Coupling Performance
As I mentioned in the 1st reply, the conveyor will accelerate (decelerate) as a function of conveyor resistance. Resistance comes in many varieties:
1. Load = empty, full, or partial loadings
2. Rolling resistance = empty, full, partial loading of inclines and/or declines
3. Ambient temperature affecting rubber rheology and idler drag
4. Belt construction of top and bottom cover thickness, fabric or steel cord construction of various types, and rubber rheology of covers
5. Belt speed
6. Cross-sectional loading of belt width
7. ....... ■
Proposal For A First
Dear Himanshu,
perhaps following approach could meet some first requirements for your calculation / answer your questions:
A Constant fill fluid coupling is a Torque Transmiting Element, based on rotation of mechanical parts and a transmission by a hydraulic fluid. So the load requirement of the conveyor must be met by the electric motor, under consideration of the transmission characteristics of the flc. 2 phases of operation are to be distinguished:
1) non - steady running (acceleration / deceleration)
2) steady running
in phase 1), the inertial forces are to be considered (acceleration of mech. parts & fluid --> attributable inertia of coupling), together with the toque / time characteristics, pls. refer Mr. Nordells reply & reputable coupling mfgr. catalogues which give very good information on principles & design requirements. This input must be used to design the drive system for nonsteady (dynamical) system states.
in phase 2), the coupling transmits the torque from drive to conv. drive pulley with a loss, attributable to the slip within the hydraulic system. This slip / loss is to be considered for the design of the drive system for steady (quasistatical) system state --> Margin on installed power.
Kind regards
R. ■
Re: Torque Transmitted By Fluid Coupling
Originally Posted by HimanshuAssume a trough belt conveyor is driven by a Constant Fill Fluid Coupling with 3 phase AC Induction motor. Is the torque supplied by this driving system to the driven conveyor system dependent on the load requirement of the conveyor (loaded conveyor / empty conveyor) ? How can the torque transmitted be formulated during static calculations of belt conveyor?
Thanks in advance......
Dear Mr.Himanshu,
The fluid coupling design definitely depends on the maximum load ( TPH ) required by the conveyor to be moved. Fluid coupling manufacturers need "absorbed power" by the motor. A particular model of fluid coupling can be fixed for a range of motor KW. The oil capacity will be different for each coupling depends on that absorbed power. These need to be known from the fluid coupling manufacturers. Fluid couplings are being replaced by Variable Speed Drives.
Regards, ■
Torque Transmitted by Fluid Coupling
Dear experts,
Assume a trough belt conveyor is driven by a Constant Fill Fluid Coupling with 3 phase AC Induction motor. Is the torque supplied by this driving system to the driven conveyor system dependent on the load requirement of the conveyor (loaded conveyor / empty conveyor) ? How can the torque transmitted be formulated during static calculations of belt conveyor?
Thanks in advance...... ■