Delta ASDA-B2 Servo Fault AL083 Excessive Current

Is your Delta ASDA-B2 servo drive showing AL083? Learn the causes of excessive current, from UVW cable shorts to analog interference, and how to fix them.

 

The Delta ASDA-B2 series is a staple in precision automation, but like any high-performance electronic system, it has strict safety limits. If your drive trips with AL083, it is reporting that the output current to the motor has exceeded its safe operating threshold.

Unlike a general overcurrent trip, AL083 often specifically points to issues in the power delivery path (the UVW cables) or signal corruption. This is a protective "hard stop" designed to prevent your drive’s internal transistors from failing. Here is a human-made guide to identifying the cause and getting your machine back into production.

Common Causes of AL083

When the ASDA-B2 detects an abnormal current spike, it is usually due to one of three main factors:

• UVW Cable Issues: Physical damage or short-circuiting in the motor power leads.
• Incorrect Wiring: The sequence of the phases (U, V, W) is swapped or one phase is missing.
• Analog Signal Interference: Electrical "noise" on the control lines is tricking the drive into outputting erratic power bursts.

Step-by-Step Troubleshooting Guide

1. Inspect the Motor Power Cable (UVW)

Most excessive current faults are found in the "copper." In environments with moving parts or vibration, cables take a beating.

• Check for Damage: Inspect the entire length of the UVW cable. Look for nicks, abrasions, or spots where the outer jacket is worn through.
• Check AWG Rating: Ensure the wire gauge (AWG) is appropriate for the drive’s power rating. Undersized wires can overheat and cause impedance changes.
• Exposed Conductors: Check the connectors at both the drive end and the motor end. A single "whisker" of copper wire touching the metal chassis will trigger AL083 instantly.

2. Verify Wiring Sequence and Phase Integrity

If you recently performed maintenance or moved the motor, your wiring might be out of sync.

• Sequence Check: Verify that the terminals on the drive labeled U, V, and W go to the corresponding U, V, and W pins on the motor. If these are swapped, the motor will vibrate or draw massive current without spinning correctly.
• Phase Loss: Check for a "lack of phase." Use a multimeter to ensure all three lines have continuity. If one phase is disconnected, the drive will over-compensate on the other two, leading to an AL083 trip.

3. Check for Analog Signal Interference

If the electrical wiring is perfect, the "ghost in the machine" might be interference. If your analog ground is tied to the wrong place, it can create a feedback loop that causes current spikes.

• Grounding Logic: Ensure the GND (Ground) of your analog signal is not misconnected to the power ground or other signal lines.
• Shielding: Verify that your analog control cables are shielded and that the shield is grounded at one end only (typically the drive end) to prevent ground loops.

The Remedy: How to Fix AL083

1. Replace Damaged Cables: If you find any evidence of worn insulation or exposed metal, do not attempt to patch it with electrical tape. Replace the UVW cable with a new, high-quality shielded motor cable.
2. Conduct Wiring Again: Refer to Chapter 3 of your Delta ASDA-B2 User Manual. Follow the wiring diagrams strictly to ensure the U, V, and W connections are correctly phased.
3. Isolate Analog Grounds: Separate your analog signal grounds from high-voltage grounds. Using a dedicated signal isolator can also help if your environment is extremely noisy.

Summary Checklist

Checkpoint	Action
UVW Continuity	Measure resistance between U-V, V-W, and W-U. Values should be balanced.
Insulation Test	Check resistance from U, V, and W to the Ground/Earth. Should be "Open."
Terminals	Ensure all screw terminals are tightened to the correct torque.
Analog GND	Ensure it is not bridged with common 24V or power grounds.