User manual BENSHAW DCB3

[. . . ] Optional features include an input for zero-speed sensing by a proximity switch, and two dry contact inputs; one for independent brake operation (useful for "anti-windmilling" on large fans, for example) and another to inhibit D. C. to one minute. POWER ASSEMBLY TECHNICAL DATA Each DCB3 Brake contains SCRs which have a minimum peak inverse voltage (PIV) rating of two and one-half times the line-to-line AC voltage and a root mean square (RMS) current rating normally selected to be three times the full load continuous current to the motor. DCB3 Brakes are rated to operate at the maximum DC current with a maximum ambient temperature of 40° C at an altitude of 6, 500 feet (2, 000 meters) above sea level. Derating of one and one-half percent per degree C above 40° C and one percent for every 330 feet (100 meters) above 3, 300 feet, must be considered when applying DCB3 Brakes. 2 DCB3 SERIES INSTRUCTION MANUAL OPTIONS The P. C. [. . . ] 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 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. 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. 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. Temporarily install a DC ammeter in series with the brakes T1 lead with the "+" side away from the DCB3 Brake. The DC ammeter must be capable of reading at least 300% (500% Heavy Duty) of the motors full load ampere (FLA) rating. 2. 3. 4. 5. 6. 4 DCB3 SERIES INSTRUCTION MANUAL 7. On the DCB3 card in the DC brake, turn potentiometers "TORQUE" and "TIME" fully counterclockwise (CCW). Turn the "ZERO SPEED SENS" potentiometer fully clockwise (CW). *Adjustments: Zero Speed Sensing: max to min. [. . . ] Turn the "ZERO SPEED SENS" pot slightly further CCW and remove the connection. The unit is now ready for use. 5 DCB3 SERIES INSTRUCTION MANUAL 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 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. [. . . ]