Hello,

The coupling is to couple motor shaft with fan shaft. So, coupling will be running comparatively at higher speed. Choose the coupling type on following considerations:

1) Allowable radial and angular misalignment, in context of the values you can achieve during manufacturing and installation

2) Resistance to torsional vibration

3) Least imbalance of radial force, by coupling

4) Ease of installation and replacement

5) Price, spares parts, availability, practice for such application and preference by you and your buyer

It is not proper on my part to opine on specific type.

Ishwar G. Mulani

Author of Book: ‘Engineering Science And Application Design For Belt Conveyors’. Conveyor design basis ISO (thereby book is helpful to design conveyors as per national standards of most of the countries across world). New print Nov., 2012.

Author of Book: ‘Belt Feeder Design And Hopper Bin Silo’

Advisor / Consultant for Bulk Material Handling System & Issues.

Pune, India. Tel.: 0091 (0)20 25871916

Email: conveyor.ishwar.mulani@gmail.com

Website: www.conveyor.ishwarmulani.com ■

Originally Posted by eng.farid.ahmed

Dears,

We are going to change the coupling design for the final fan in cement plant from gear coupling to steel lamina coupling (Disc coupling). The fan characteristics are as the following;

Fan capacity = 732,400 m3/hr

Static head at inlet = 303 mmH2O

Electric motor power (AC) = 1,150 KW

Speed control (frequency converter) = Max speed 980rpm "For normal operation, speed = 750 rpm most times"

For the coupling selection steps:

1- The rated system load = (9550 * 1150) / 750 "normal speed" = 14,643 Nm

2- The service factor is about 1.5

3- Temp. factor is about 1.

4- The max. torque should be lower than the max. coupling torque, so How can we calculate the max torque for this fan like the starting torque?

5- the dynamic torque load must be lower than the coupling fatigue torque "TKW should be equal or more than TW*FF*(1.5/(FB-1)", where;

TKW = coupling fatigue torque

TW = system dynamic torque load

FF = frequency of the dynamic load

FB = service factor

So How can we calculate TW & FF for our fan?

I look forward to receiving your technical reply, please.

BR,

Farid

You need to develop a Holzer Table. Nowadays you can do this using Excel and inserting various TW's to find out the FF's. A good text on torsional vibration will provide the construction details of the table. I haven't used Holzers since 1977 ans that was for Nissan truck analyses where only 350bhp was involved. I imagine you will battle for the radial inertia of the fan since you seem to be questioning the original suppliers' data. Easier: on the bright side: coupling suppliers know their business inside out and will be sure to answer your concerns properly. I've had a coupling salesman fine tune a driveline, same day, in situ. Very impressive. ■