DCB5A115 DCB5A230 DCB5A400 CETA12 CETA124AAA 3600VA 138VA 360VA CETAFA11 - Datasheet Archive

 

English Issue 2 Powerbrake Terminal functions DCB5A D.C. Injection Brake Unit A1 A2 N.B. The DCB5A is fully interchangeable with

 

Technical Specification English Issue 2 Powerbrake Terminal functions DCB5A D.C. Injection Brake Unit A1 A2 N.B. The DCB5A is fully interchangeable with the former DCB5. The DCB5 was identified by a light grey enclosure with a black lid. The DCB5A is all light grey. Supply } voltage _ 23 24 n.o. contact }(closed when relay is energised) }Line contactor relay _ With the increasing need for higher production rates and reduced cycle times, many electric drives benefit from reliable and accurate braking to decelerate or stop the motor. 13 14 Disc and shoe friction brakes are commonly used, but suffer from the usual mechanical disadvantage of wear and tear, risk of contamination or overheating if operated too frequently. Brake }n.o. contact relay is energised) } contactor relay (closed when 95 96 07 08 _ }n.c. contact relay is energised) (closed when Fault } relay n.o. contact }(open when relay is energised) S1 Brake initiation S2 }n.o. contact ­ close to commence brake sequence _ Electrical braking methods are virtually maintenance free and include plugging, regenerative and d.c. injection. Plugging, which involves reversing the supply to the motor, is difficult to control and imposes considerable stress on the motor windings and bearings. Regenerative braking, which uses resistive elements to absorb the kinetic energy in the motor, becomes less effective as speed reduces and does not provide a positive stop. D.C. injection braking, which offers fast, controlled deceleration down to zero speed by neutralising the rotating magnetic field in the motor, is an acceptable compromise in many applications; the stored energy is largely dissipated in the motor itself, dispensing with the need for bulky external devices. The DCB5A is a self-contained braking unit for three-phase induction motors rated up to 5,5kW (12A max.). The only external component required (in addition to the normal starter) is a contactor suitable for AC1 duty at 25A. The DCB5A provides independent adjustment of braking current/torque and time, so that the deceleration response can be optimised to suit motor and load inertia. 50/60Hz supply frequency is detected at the start of each braking cycle to ensure that the torque setting is unaffected by the local supply network. Additional flexibility is afforded by facilities for remote time setting/selection. Separate control relays for line and brake contactors ensure that motor switching occurs in an orderly sequence, with no risk of overlap on three-phase and d.c. connections. A fault relay is fitted for remote signalling and interlocking. Fault monitoring includes motor temperature (via PTC thermistors) thyristor failure and excessive braking time (brake time potentiometer disconnected). A thermal trip will auto-reset on cooling. Thyristor, braking supply or semiconductor fuse failure will cause a permanent trip which can be reset by interrupting the control supply to the DCB5A after the cause has been rectified. The DCB5A is housed in a 100mm wide plastic enclosure, furnished with three LED status indicators, for EN35 rail or surface mounting. Note that injection braking cannot operate in the event of supply failure. A risk assessment should therefore be undertaken to determine whether the application requires additional backup. D.C. injection brakes do not lock the motor in the rest position after the selected braking time has elapsed. Contact loading 10mA, 24V d.c. _ T1 T2 T3 Potentiometer connections T1 ­ T2 for internal adjustment }Linkremote adjustment connect external potentiometer For As variable resistance across T1 ­ T3 _ P1 P2 }Thermistor connections Link to disable _ L1 L2 }Network (motor) voltage }Braking current _ U V Technical specification Module supply voltage: (Must be specified) 110.120V 220. 240V +10% - 15% 380. 415V 50-60Hz 6VA N.B. Network/motor voltage is 380. 415V three-phase } _ Braking current: 40A max. for 2s 30A max . for 10s Subject to duty } Applicationscycle. See Info. _ Braking time: Adjustable 0.1-15s via integral potentiometer or 0.1-30s via 20K external potentiometer _ Indicators: Green - Power On Amber - Braking Red - Fault (see details page 2) _ Line contactor relay: Energised during normal motor operation, de-energised while braking and when motor is off. _ Brake contactor relay: Energised during braking only. See Operating sequence diagram. _ Fault relay: Normally energised, de-energised when a. Disconnected brake time potentiometer b. Motor temperature is high c. Thyristor or supply failure _ Order references Relay ratings: Control Modules: DCB5A 5.5kW 110 - 120V control DCB5A 5.5kW 220 - 240V control DCB5A 5.5kW 380 - 115V control (n.o. and n.c. contacts) Resistive load: 5A max. _ DCB5A115 DCB5A115 DCB5A230 DCB5A230 DCB5A400 DCB5A400 _ 63FE semiconductor fuse 01.000040.058 _ Brake Contactor CETA12 CETA12 CETA124AAA CETA124AAA (AAA=coil voltage e.g. 230) A.C. inductive load (B600): Make: 3600VA 3600VA D.C. inductive load (P150): Make: 138VA 138VA Break: 360VA 360VA (415V max.) _ Break: 138VA 138VA (120V max.) _ Adjustments: Braking torque (current): 10-100% rated maximum Braking time: 0.1-15s through integral or external 10k potentiometer _ N.O.+N.C. aux. contact block CETAFA11 CETAFA11 2N.O.+2N.C. aux contact block CETAFA22 CETAFA22 Ambient temperature range: -10° to+50° C C _ _ Star-Delta Timer TK5 64.240707.000 1.5 ­ 30s adjustable delay 110 ­ 415V 50/60Hz control supply Operations/h: Dependent on braking current. See technical data overleaf _ Terminal cable capacity: 1 x 4mm2 _ Enclosure rating: IP20 _ Weight: 0.6kG P1 of 4 Technical Specification English Issue 2 Applications information Operation The operating sequence is shown on the graph opposite. The d.c. braking current is injected into two motor terminals after the three-phase supply has been disconnected. The magnitude of the braking current ­ and braking torque ­ is dependent on: See Typical Wiring Diagrams opposite. Both circuits operate normally during starting and running. In the DOL circuit, the normal stop button initiates braking. As the line contactor L de-energises, isolating the motor from the threephase supply, the connection between terminals S1-S2 closes and the braking sequence commences. After 250ms (t1), the brake contact 13-14 closes, energising the brake contactor B, connecting a.c. power to L1-L2 and the motor to U-V on the DCB5A. After a further 100-120ms (t2), braking current is injected into the motor windings. When the set braking time has elapsed, contact 13-14 opens, contactor B de-energises and supply and motor are again isolated, ready for restarting. The star-delta configuration works in a similar manner, except that a stay-put brake button initiates the braking sequence. When the brake contactor B energises, the star contactor S also energises, connecting the motor windings in star for maximum braking effect. The brake command button must be reset or unlatched before the motor is restarted; if the button is released during the braking sequence, the motor will coast to a stop. a. b. The stator winding resistance of the motor and The setting of the torque control (adjustable 10 ­ 100%) In practice the braking current should be adjusted to be no more than twice the motor rated current, i.e. IB 2IN. Higher currents can cause saturation of the stator windings and lead to overheating, with no corresponding increase in braking torque. The braking time is dependent on motor and load characteristics, as well as braking current, in accordance with the following approximate formula: 0.1 x ILR2 x J x n tB = IB2 x TLR seconds where tB is the braking time ILR is locked rotor current in A IB is braking current in A TLR is locked rotor torque (Nm) J is the total moment of inertia of motor and load in kgm2 N is the motor speed in rpm Alternative braking times can be selected to compensate for varying motor speeds and/or loads by using the potentiometer terminals T1, T2 and T3 on the DCB5A: tB 1 Internal potentiometer O T1 O T2 Operating sequence -t1- -t2- -t3- -t4- MOTOR RUNNING MOTOR STOPPED O T3 tB2 External potentiometer START BUTTON OPERATED L ENERGISES STOP BUTTON OPERATED L DE-ENERGISES B ENERGISES With 10k pot, tB2 = 0.1-15s With 20K pot, tB2 = 0.1-30s The brake time setting should not be significantly longer than the actual deceleration time of the motor, since once it has stopped, continued d.c. injection merely causes unnecessary heat dissipation in the motor. INJECTION COMMENCES INJECTION CEASES RESTART B DE-ENERGISES Fault LED diagnostics The DCB5A will display the nature of a fault by the speed at which the red fault LED flashes as follows: If it is not possible to match the set and actual brake times, a zero speed detection sensor can be used to turn off the braking current by opening connections to S1-S2 on the DCB5A. Having established the required braking current and time, the permissible braking duty cycle can be determined: IB max 30A Fault LED on IB max Fault LED off 1. 15A 2. 3. 0 5% 10% Duty cycle 20% 4. Thermal fault (PTC motor thermistor) Fault LED on No electricity supply to thyristor braking circuit or blown fuse Fault LED flashing (500ms on / 500ms off) Thyristor failure Fault LED flashing (100ms on / 900ms off) Disconnected brake time potentiometer Fault LED flashing (900ms on / 100ms off) The duty cycle is the ratio of braking time to total operating time. Thus if IB is 30A for 10s, there must be an interval of 190s before the next braking command. This interval is necessary to avoid overheating in the DCB5A and the motor. P2 of 4 Technical Specification English Issue 2 Typical wiring diagrams DOL starter, 415V control, Internal tB setting B Supply F1 L1 O L2 O L3 O Isolator CF1 CF2 1O 3O 5O L L B L A1 A2 23 24 13 14 95 96 B 07 08 S1 S2 O O O O O O O O O O O O Stop/ Reset 415V LINE BRAKE POWER BRAKE FAULT FAULT TORQUE DCB5A Start L TIME Overload MTE 2O 4O 6O O O O O O O O O O O O O T1 T2 T3 P1 P2 L1 L2 U V B M 3 Star-Delta starter, 240V control, External tB setting Supply L1 L2 L3 N Isolator NL Alarm Brake CF1 1O3O5O M D B Overload A1 A2 23 24 13 14 95 96 M 2 O 4O 6 O 2 O 4 O 6 O U1 V1 W1 U2 V2 W2 230V LINE M 3 BRAKE POWER BRAKE FAULT D DCB5A Stop/Reset 95 96 07 08 S1 S2 O O O O O O O O O O O O FAULT TORQUE TIME MTE B Start O O O O O O O O O O O O 1 M T1 T2 T3 P1 P2 T L1 L2 U V 2 A2 B A1 S D A2 S A1 D S M 7 S 8 1M B F1 A2 A1 M B P3 of 4 Technical Specification English Issue 2 Installation and circuit protection Dimensions (mm) A 63A fast-acting semiconductor fuse F1 should be connected in series with DCB5A terminal L1, as shown, together with 4A HBC control circuit fuses. DCB5A Weight 0.6kG 100 Since contactor B switches off load, it can be rated for AC-1 duty at 2.5IN. Line and brake contactors should be electrically interlocked to further guard against simultaneous connection of a.c. and d.c. power. Note that the motor will coast to a stop if the DCB5A is incorrectly set (current too low, braking too short) or if d.c. injection does not occur because of a bad connection, for example. The fault relay is normally energised, with contact 95-96 closed and contact 07-08 open. If a fault occurs, the relay de-energises, opening 95-96, closing 07-08, turning off injection current and opening 13-14. The fault relay monitors presence of braking supply voltage, braking thyristor firing and motor temperature via thermistors. If the braking time potentiometer becomes disconnected or the internal potentiometer link T1 ­ T2 is not fitted, the fault relay will de-energise (trip). Interrupting the control supply when the fault has been eliminated effects a reset. 116 EN35 rail mounted 53.5 113 surface mounted O OOOOOOOOOOOO 8475 66 DCB5A MTE OOOOOOOOOOOO O 5 Motor thermistors in accordance with BS4999 BS4999 Part III, can be connected to terminals P1-P2. The fault relay will trip (deenergise) if the total thermistor resistance exceeds 2.5k approx; automatic reset occurs when the resistance drops to 750 . Alternatively, a normally closed bi-metallic thermostat can be used. To avoid inductive pick-up, thermistor wiring should be a twisted pair and/or screened cable. This cable should not be run parallel to power cables for long distances as a precaution against capacitive pickup. If temperature monitoring is not employed, terminals P1-P2 must be linked together. Power factor correction capacitors, if fitted, must be connected on the supply side of the system i.e. immediately after the isolator. Electromagnetic Compatibility It is recommended that normal good wiring practice be observed. Control cables, esp. low level cables (external time setting potentiometer, motor thermistors, heatsink thermostat etc.) should be separated from power cables by 300 mm or as far as practicable. Where proximity is unavoidable, low level cables should cross power cables at right angles. Suppressors should be fitted across contactor coils or similar inductive components. WARNING: Semiconductor devices transmit leakage current. Before installing or attempting adjustments or maintenance on DCB5A unit, starter or motor, the supply must be disconnected. Setting-up procedure 1. Because the motor winding resistance changes with temperature, adjustment of braking torque current control should be carried out while the motor is at its normal operating temperature. 2. Set brake time at maximum and brake torque at minimum (10%). 3. Start and stop the motor, with maximum anticipated load, slowly increasing the brake torque setting (clockwise) until required stopping performance is obtained. 4. Reduce the brake time setting until the brake LED indicator goes out just after the motor has stopped. Note: Violent braking should be avoided. It should not normally be necessary to exceed a midpoint setting for the torque control. The rms braking current should be checked with a moving iron ammeter connected in series with terminal U of the DCB5A; braking current must not exceed 2IN. Excessive braking duty may damage the DCB5A and/or overheat the motor. Council of European Communities Directives: The products in this publication conform to relevant EEC Directives and EN Standards. Installation and use of such products must be carried out by competent, properly trained personnel, complying with any instructions supplied by MTE. Liability for improper incorporation, assembly, use, processing, storing or handling of goods remains the sole responsibility of the individual, or company carrying out such work. This publication is for information only. Whilst every care has been taken in the preparation of this leaflet, no liability is accepted for any consequence of its use. No licence to use any patent should be assumed. All dimensions are approximate only and subject to change without notice, as are other technical features resulting from continual development and improvement. ENTRELEC-MTE LIMITED Stephenson Road Leigh-on-Sea Essex SS9 5LS Telephone +44(0) 1702 421124 Fax +44(0) 1702 510453 06 012325/ 2E/ 302 P4 of 4