Applicable Systems
AC500
AC590
ACS580
ACS880
Symptoms
The ABB IRC5 robot controller displays alarm 37109, indicating brake release failure. One or more axis brakes failed to release when commanded, preventing safe robot motion.
Possible Causes
- Brake contactor K42 or K43 faulty or not energizing
- Brake power supply fuse blown or power wiring damaged
- K44 contactor (brake monitoring) defective
- Brake coil in the motor shorted or open circuit
Troubleshooting Steps
- Step 1: Check contactor K42 and K43 coil energization and contact operation
Contactors must energize when brake release is commanded; listen for clicking sound - Step 2: Measure 24VDC brake voltage at K42 and K43 contactor outputs
Voltage must be 24VDC when brake release is commanded; if absent, check upstream power supply - Step 3: Test K44 contactor for proper operation
K44 monitors brake release; if faulty, it may prevent the brake release sequence - Step 4: Measure brake coil resistance at motor junction box
Coil resistance should match specification; open or shorted coil requires motor service
How to Reset
To reset: 1) Fix the brake circuit fault. 2) Execute a brake test from the teach pendant. 3) If the brake passes the test, the alarm can be cleared. Caution: Never attempt to move the robot manually when brakes are not functioning - the arm may fall causing injury or equipment damage.
Frequently Asked Questions
- Q: What voltage is required for ABB robot brakes?
ABB IRC5 axis brakes typically operate on 24VDC. The voltage must be present at the brake coil when the brake release command is active.
- Q: Can I move the robot if alarm 37109 is active?
No. The robot cannot be moved in automatic mode when brake release fails. In manual mode, the brakes must be manually released using the brake release tool, but this should only be done for maintenance purposes with proper safety precautions.
Source: ABB IRC5 Operating Manual - Trouble Shooting, Document 3HAC020738-001, Alarm Code 37109
Category: Robot