© Siemens AG 2015 FLENDER Standard Couplings Fluid Couplings — FLUDEX Series General information FN series – drive via the housing 103 101 153 102 Part 2/3 of the flexible coupling Part 10 of the flexible coupling Flexible elements Part 11 Brake drum Blade wheel (outer wheel) Cover Fusible safety plug Blade wheel (inner wheel) Shaft Hub carrier (large delay chamber) Filler plug Oil locking screw - delay chamber Screw plug (oil drain) Working chamber FND 105 2/3 10 12 2/3 Damming chamber 11 11 32 101 102 103 105 106 120 153 173 163 10 12 106 120 G_MD10_EN_00118 Large delay chamber FNDB 173 32 163 FLUDEX FN series couplings have a larger delay chamber than the FV series.
The delay chamber is designed as a hub carrier (120) and is mounted on the motor shaft. The hub carrier is flange-fitted to the housing (101, 102) of the FLUDEX coupling. Output is via the blade wheel (105) and the shaft (106) to the flexible N-EUPEX coupling connecting to the gear unit or driven machine. With types FND, FNDB and FNDS the coupling can be dismounted radially without moving the coupled machines. The normally stronger motor shaft bears the weight of the hub carrier (cast version) and the main coupling. The gear unit shaft carries only the brake drum or disk and the output-side part of the flexible coupling.
At the same time, the principle of the drive- side delay chamber with the capacity for increasing torque time- dependently is retained. FN couplings have the same fields of application as FV couplings. However, they offer special advan- tages in the brake disk design because of the weight distribu- tion. Because of the larger delay chamber, FN couplings enable even softer starting than FV couplings. Torque limitation during motor starting is approx. 1.3 times T N . A further advantage of types FNDB and FNDS is the favorable weight distribution. Depending on the series selected, different starting characteristics arise during starting.
Motor torque/coupling torque Coupling torque over starting time N / 2.5 G_MD10_EN_00119a 2.5 T coupl FA.. / FG.. G_MD10_EN_00120b T T Torque 2.0 Mot T 2.0 FV.. 1.5 s = 100% - FA.. / FG.. 1.5 FN.. 1.0 s = 100% - FV. 1.0 s = 100% - FN.. 0.5 0.5 0.0 0% 50% 100% 0.0 Starting time FLUDEX series: Motor speed n 0 n 1 / 13 13/9 Siemens MD 10.1 · 2015 Series Description FA../FG.. Basic coupling without delay chamber FV.. Coupling with delay chamber FN.. Coupling with large delay chamber