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CWP Training Seminar. Chapter: 14 Coupling between Gear Box and Motor. Purpose and Design Consumed and Provided Power (PVT, PM) Alarm and Trip Table AUTOGUARD BIBBYGUARD DESCH. Purpose and Design. Coupling breaks if the power consumed gets too high Coupling provides safety functions
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CWP Training Seminar Chapter: 14 Coupling between Gear Box and Motor Purpose and DesignConsumed and Provided Power (PVT, PM)Alarm and Trip Table AUTOGUARD BIBBYGUARD DESCH Standardseminar Jan.2001
Purpose and Design • Coupling breaks if the power consumed gets too high • Coupling provides safety functions • Standard: > ZSK 177 pneumatically operated < ZSK 177 spring actuated coupling • Standard trips: - Torque in process section too high - Axial pressure caused by product too high- Fault in coupling monitoring device - Coupling slips more than 4 revolutions in 2 minutes - Fault in coupling monitoring device- Fault in underwater pelletisation- Emergency OFF is actuated Last Update: 01.2003/by:MK<Kap>.2
2 x Mscrew_max x ns PVT max = 9'550 2x 100'000 Nm x 230 min-1 PVT max = = 4'816 KW 9550 Consumed and Provided Power (PVT, PM) • Consumed Power PVT limited by the torque rating of the screws (Mscrew): • Provided Power PM is normally based on PVT max, adding gearbox losses <=5%: PM = PVT x 1.05 • Example: ZSK 300, gearbox 261F200 (Mscrew_maxl =100,000Nm), n=230rpm PMmax = 4816 x 1.05 = 5'060 kW Last Update: 01.2003/by:MK<Kap>.3
Alarm and Trip Table Process section Gear unit Coupling Efficiency = 95 % Motor Torque at coupling [%] Absorbed power at nnom: Function / Safety feature Motor [%] Process [%] Normal extruder operation 105 105 100 Warning flashing light torque 105 105 100 Motor trip due to excessive current. Effect: Dosing off.Coupling opens and breaks power. 110 110 105 Coupling opens and breaks power. Effect: dosing off.ZSK 25-70: Motor trips; ZSK 92-380: Motor runs idle 115 = switching point 115 110 Special cases: Spring actuated friction coupling slips. Effect: Motor and dosing off. 130 = switching point 130 125 Last Update: 01.2003/by:MK<Kap>.4
AUTOGUARD – Spring-loaded Coupling Last Update: 01.2003/by:MK<Kap>.5
BIBBYGUARD - for ZSK 50 Mcc Last Update: 01.2003/by:MK<Kap>.6
DESCH – Principle of Function Speed monitor Flexible coupling Friction discs Cylinder exerting pressure Speed monitor Motor side Gearbox side Air = Torque Flow Last Update: 01.2003/by:MK<Kap>.7
DESCH - Dismantling the Friction Discs Dismantling the friction part: 1. Release the screws on the motor side and mark. 2. Push back the hub (motor side). 3. Secure coupling (friction part) before dismantling with the ring bolt 4. Close the coupling (compressed air) 5. Secure friction discs with supplied clips 6. Vent the coupling 7. Remove the screws on the gear unit side 8. Lift out the friction part with lifting gear. Last Update: 01.2003/by:MK<Kap>.8
DESCH – Determination of Pressure Setpoints Pmot[KW] MVT [%] Pmot: Motor Power (normally indicated on 0..100% Amp Display); Scale different for each machine!! MVT: Nominal Torque on screw shaft (100%=MScrew_max) 1-3: Operating Values; Determined during test runs at slowly increasing feed rates 4-5: Overpressure Setpoints (PSH, PSHH) for monitor switch;Determined by calculationResult for this case: Setpoint PSH = 3.4 bar g Setpoint PSH = 4 bar g 130 6'000 120 110 5'000 100 3 90 4'000 80 70 2 3'000 60 1 50 2'000 40 30 20 1'000 10 4 5 Air pressure [bar g] 0 1 2 3 4 5 Last Update: 01.2003/by:MK<Kap>.9
Desch – Local Control Box • Net Pressure Reducer PCV • Fine pressure reducer • Coupling ON/OFF Ctrl Valve • Local Pressure Gauge • Pressure monitor switch PSH • Quick-action venting valve Vent R R ¼" to coupling 6 A P Ø 10 mm 5 4 Monitor SP=0.2-12 bar 3 2 Air supplySP 0.5 - 6 bar 1 4-6 bar Last Update: 01.2003/by:MK<Kap>.10