14.1 Introduction:
Generally, industry is using fluid coupling or soft starters for bucket elevators,
DPC and belt conveyor drives. It is observed that frequency of fluid coupling
breakdown are more due to misalignment of coupling, damage of fusible plugs
resulting in huge loss of production, hence we have started thinking that this can
be avoided by using VVVFD starter, after discussion with OEM/consultants and
convinced with our solution.
Hence we decided to go with all the conveying equipment with VVVFD Drive,
advantage and disadvantages are as below.
14.2 Conventional Method:
Following are the Major Electromechanical Hardware’s required to operate Belt
Conveyor / Deep Pan Conveyor / Bucket Elevators drive
- Mechanical Equipment
- Mechanical Fluid Coupling to sustain Starting High Torque & Smooth Start
of the Drive - Electrical Equipment
- IMCC DOL/Star Delta starter Feeder of adequate rating.
- Power Factor Improvement Capacitor Back/APFC
With the conventional system & involvement of above Hardware’s during Operation
& Process Control, Practically Experienced the Limitations & following Disadvantages
of system are as under:
- System Installation time: - Fluid coupling is taking more Installation time as
compared to direct coupling. - Mechanical Fluid coupling will have 2% to 6% slippage which result into
reduction in speed. - During operation, some time when hold back of gear box failed which resulting
a reversing movement with high speed, accelerate to a runaway condition &
cannot sustain by the fluid coupling & get blown of, which can kill or injure
personnel (fatal accident), or destroy drive train components, tear expensive
belting & chain or cause considerable other damage, as well as the massive
clean-up of material spillage than can occur. - System required periodic maintenance.
- Electrical Motor Design & Hardware’s IMCC DOL Feeder with necessary
switchgear used to start /stop the drive. - Stresses on motor winding will high because of 4-5 times starting torque
have impact on motor life.
Deep Pan Conveyor / Bucket Elevators 14. Selection of Starter & Speed Control for Belt Conveyor /
CONVEYOR / DPC /BUCKET ELEVATORS