3-2 When the Alarm Contact is Activated 3-2 When the Alarm Contact is Activated In principle, the alarm contacts of the Regenerative Braking Unit are activated when the Braking Re- sistor is overheated by excessive regenerative energy or frequent braking. As a countermeasure, review the capacity of the Braking Resistor, model and number of Regener- ative Braking Units, as well as Inverter deceleration time. Incorrect wiring and improper receiving voltage can be also considered as a cause of an alarm. Use the flowchart to diagnose the problem: 3 Alarm contact is activated. Is the main element (IGBT) defective? (*1) YES Maintenance Operations Regenerative Braking Unit is defective.
Replace or repair the unit. NO Is the resistance higher than "connectable resistance" selected? NO YES Review the resistor selection. Are the units in parallel operation? YES NO During operation, are the operation LED indicators of all units lit? NO YES Check the wiring and DIP switch settings are correct. Does either the master or slave unit have a wire breakage? YES Replace the resistor. Review resistor selection. Is the operation LED indicator lit in any other status than Inverter deceleration (during Inverter acceleration, or in standby status)? Is the Inverter's receiving voltage outside ±10 % of the rated voltage? Correct the voltage.
NO YES YES NO NO Is the control circuit terminals correctly wired? (For single operation, this terminal need not be connected.) Be sure to wire correctly and securely. NO Is the main circuit terminals correctly wired? YES YES Be sure to wire correctly and securely. NO The Regenerative Braking Unit is defective. Replace or repair the unit. *1. For the IGBT check procedure, refer to "4-4 Checking the Main Element"(Page 4-5). 3-2