User manual BENSHAW DCB3

[. . . ] brake and allowing the motor to be restarted. A "Time" adjustment limits the maximum time that the D. C. The stopping brake torque adjustment enables smooth motor deceleration to zero speed providing controlled stopping times. This adjustment procedure reduces hazards associated with coasting machinery, overhauling loads, etc. [. . . ] It drops out when the motor is started, it stays out when the motor power is removed and during braking, and it energizes when the motor stops or the brake time is over. Since the zero speed sensing circuit needs voltage at the motor to detect rotation, the motor may still be turning when the relay is energized if the brake current stops while the motor is still turning. Because the prox switch option makes the "Zero Speed" LED pulse with each switch transition as the motor comes to a stop, the contacts will chatter. Therfore, these two features should not be used together. 3 DCB3 SERIES INSTRUCTION MANUAL CONNECTION PROCEDURES FOR DC INJECTION BRAKING WARNING ! Equipment is at line voltage when AC power is connected. Pressing "STOP" push-button does not remove AC mains potential. All phases must be disconnected before it is safe to touch motor terminals or control equipment parts. REMOVE AC POWER 1. Connect two phases of the power input from the motor starter to terminals L1 and L2. Wire should be sized according to the motor current. Wire sizing may be determined by consulting local and/or NEC recommendations. Connect three phases of the starter output to the motor to terminals T1, T2 and T3. Be sure they are connected between the motor overload and the motor. T1 should be on the same phase as L1, and T2 should be on the same phase as L2. Open the control connection to the coil of the motor starter and connect DC brake terminals 7 and 8 in series with the coil of the motor starter. It may be desired for motor protection, that the starter overload, if tripped, should inhibit the DC brake. To do this, a set of N/O overload contacts should be connected to terminals 16 and 17 on the DC brake PC board. If the overload does not have a set of N/O contacts available, use a pilot relay circuit. If desired, the optional dry contact inputs for independent brake and/or brake inhibit 5 can be connected. Connecting a normally-open contact to terminals 14 and 15 will allow independent D. C. brake operation whenever the motor isn't running and the contact is closed. Connecting a normally-open dry contact to terminals 16 and 17 will allow braking to be inhibited whenever the contact is closed. NOTE these inputs are for dry contact connection only. Do not connect any control voltages, either AC or DC, to these inputs or erratic operation and equipment damage could result. The DC current through the motor must be measured to properly adjust its level. [. . . ] Pressing "STOP" push-button does not remove AC mains potential. All phases must be disconnected before it is safe to touch motor terminals or control equipment parts. REMOVE AC POWER USING POWER FACTOR CAPACITORS Power factor correction capacitors can be used in conjunction with the DCB3 Brake; however, the capacitors must be added ahead of the brake and never between the brake and the motor. If the capacitors are installed between the brake and the motor, serious damage to the brake and/or the motor may result. INDUCTION MOTOR TEMPERATURE MEASUREMENT The motor's stator winding temperature rise can be determined by recording the winding resistance at room temperature before operation and after the motor has reached running temperature at full load. Using a digital ohmmeter capable of reading milliohms, calculate the stator winding temperature rise by using the following formula: Temperature Rise: T= (RF/R)-1) (234. 5 + t) (Degrees C) RF = Resistance in ohms of final temperature measurement R = Resistance at beginning of test t = Room temperature at beginning of test PREVENTATIVE MAINTENANCE The components of the DCB3 Brake will not deteriorate with use; however, some routine inspection and maintenance is suggested. [. . . ]