hello group looking for techno commercial comparison between VFD and mechanical fluid coupling.

Hi Salim,

Do you have a specific application in mind?

Advantages of VFD include:-
soft starting capability
Better power factor performance
higher system efficiency
Lower life time maintenance costs
Better performance with line side disturbance
Better availability

Advantages of FC include:-
Lower first cost
claimed better reliability
Footprint

AC VFD Is very use full for your application, Its save Power & better power factor & if you use good quality drive with filter its also help in maintain harmonics low. you can use passive filter if there is more distance.

Comparison about AC 4 quadrant drives and hydraulic couplers application for downhill conveyors.
1. Energy saving
4Q drives boast perfect energy saving goal, can reach high power factor up to1, with energy feedback functions,regen energy can be returned to main supply,low heat loss of 1%.
Hydrolic couplers feature low energy saving effect, will waste 75% of energy at low speed.
2. Start performance
4Q drives with low harmonic,no harmonic pollution on main supply,low start current of 50% rated current,full process of start controllable,start point and ramp time settable
Hydrolic couplers are not able to improve start performance, its start current up to 5~7 times of rated current that cause big shock on main supply and motors
3. Installation
Simple and easy to drives,only connect by cables
Hydrolic couplers are installed between motors and load,motors needed to move, occupy large space
4. Safety
On failure of drive,motor can run in bypass way
On failure of hydralic couplers,motors will stop for repairing of coulplers
5. Running precision
4Q drives can realize acurate adjustment of speed that is suject to output frequnecy.speed can remain constant when load changes.
Hydrolic couplers with low precision, speed is controled by oil qty and load. Speed changes with load.
6. Maintaining cost
Low cost for 4Q drives, no need of consumption material
Hydrolic couplers need regular relacement of oil