The gate drive board (which controls the IGBTs) often contains the current feedback circuitry. Damage from moisture, dust, or vibration can cause short circuits or open traces that manifest as A910.
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In the world of high-precision motion control, the Yaskawa error code A.910 is a specific warning signal used primarily in Sigma-5 and Sigma-7 series servo drives.
While it may seem urgent, A.910 is technically a warning (minor fault) rather than a hard alarm. It serves as a preemptive notification that the system is approaching an overload condition. Ignoring this warning typically leads to a full system shutdown via A.710 (Instantaneous Overload) or A.720 (Continuous Overload) alarms. What Does Error Code A.910 Mean?
The A.910 error signifies an Overload Warning. By default, Yaskawa drives trigger this warning when the system reaches 20% of the time required to hit a critical overload alarm threshold. It is a safety feature designed to protect the servomotor from overheating or mechanical damage by giving operators time to adjust the load or duty cycle before a shutdown occurs. Primary Causes of A.910
Several factors can trigger this warning, ranging from mechanical fatigue to improper parameter configuration:
Excessive Mechanical Load: The most common cause is a load that exceeds the motor's rated torque capacity due to mechanical binding or increased friction in the system.
Aggressive Duty Cycles: High-frequency acceleration and deceleration or operating at peak torque for extended periods can build up heat faster than the motor can dissipate it.
Improper Parameter Settings: The threshold for this warning is controlled by parameter Pn52B (Overload Warning Level). If this is set too low (e.g., 10–20%), the warning may appear prematurely during normal operation.
Wiring or Feedback Issues: Faulty contact in the motor or encoder cables can cause the drive to "misread" the torque requirements.
Capacity Mismatch: If the SERVOPACK and servomotor capacities are not properly matched, the drive may struggle to maintain current levels, triggering an early warning. Troubleshooting & Remediation Steps
To resolve an A.910 error and prevent it from escalating to a hard stop, follow these diagnostic steps: Yaskawa.eu.com Σ-7C SERVOPACK - Troubleshooting Manual
The monotone whine of the Yaskawa Sigma-7 servo amplifier was the only sound in the entire packaging line. It was a sound that Elias, the lead robotics technician, usually found comforting—a mechanical heartbeat. But today, the heartbeat had flatlined.
Elias stared at the HMI screen. The conveyor belt was frozen. The robotic arm, usually a blur of yellow metal and precision, hung limp over a pallet of boxed goods. The operators stood back, arms crossed, looking at Elias with the weary expectation of people who knew the shift was about to get much longer.
In the center of the control panel, the tiny seven-segment LED display on the drive blinked a steady, accusing red. yaskawa error code a910
A910.
Elias felt a knot tighten in his stomach. He didn't even need to pull out his phone to check the manual; he knew this one. It was the bogeyman of Yaskawa error codes. The white whale.
"Overload," Elias muttered, wiping grease from his hands with a rag.
"Overload?" asked Sarah, the shift supervisor. "But the arm isn't moving. How can it be overloaded if it’s standing still?"
"That’s the tricky part, Sarah," Elias said, popping the cover off the servo drive cabinet. "A910 isn't just 'I'm carrying too much weight.' It’s 'I'm working too hard to do absolutely nothing.'"
He connected his laptop to the drive’s USB port, firing up the SigmaWin+ software. He needed to see the trace data. The code A910 meant the motor was drawing excessive current for a prolonged period, or the drive estimated that the thermal capacity of the motor was exceeded.
But Elias knew the robot. It was a load-and-unload bot. It barely lifted fifty pounds. It shouldn't be overheating.
He looked at the status monitor. The command speed was zero. The torque reference, however, was spiking at 140%.
"It's fighting a ghost," Elias whispered.
"What?" Sarah leaned in.
"Look at this," Elias pointed to the digital waveform on his screen. "The motor is trying to move, but something is physically locking it in place. The drive is dumping current into the windings to try and overcome the resistance, but it can't, so it trips the overload protection before the motor burns out."
"Brakes?" Sarah suggested. "Maybe the brake didn't release?"
"That was my first guess," Elias said. "But if the brake was stuck, we’d hear it groan or smell burning friction material. This is silent."
Elias walked over to the robot base. The mechanical brake unit was encased in a housing behind the motor. He put his ear close. Nothing. He reached out to nudge the arm manually—it was rock solid. The servo lock was engaged, holding the position with an iron grip. The gate drive board (which controls the IGBTs)
He went back to the laptop. He disabled the servo lock (Servo Off) and switched the drive to JOG mode. "I'm going to try to jog it forward, one millimeter. Just a tick. Stand clear."
He hit the button. Click. The drive faulted out immediately. A910 reappeared instantly.
"Instant overload," Elias scratched his chin. "That’s not a mechanical jam. A mechanical jam would let it build up torque for a second or two before tripping. This is happening instantly."
He looked back at the motor cables. They were thick, black, industrial things, running from the drive to the motor. He traced the line with his eyes. It looked fine. No cuts, no burns.
But then, he saw it. A faint shimmer in the air near the cable tray.
"Elias, what are you looking at?" Sarah asked, seeing him squint.
"Sparks," Elias said. "Or... the memory of sparks."
He knelt down by the cable tray. During the last maintenance cycle, a zip tie had been pulled too tight around the main power cable (the UVW phases). Over months of the robot's repetitive twisting motion, that sharp plastic edge had slowly sawed its way through the insulation.
Elias gently touched the cable. It was hot. Not warm—hot.
He pulled out his multimeter. He checked the resistance between the U and V phases at the motor disconnect.
Zero.
"A dead short," Elias sighed. "Sarah, we found the ghost."
The cable had worn through, shorting two of the three power phases together
The Yaskawa A.910 error code is a common Overload Warning typically found on Sigma-series servo drives, such as the Sigma-7, Sigma-5, and Sigma-3. It serves as a pre-alarm notification that the motor or drive is operating near its thermal limit, allowing operators to intervene before a full shutdown (like an A.710 or A.720 fault) occurs. Understanding the A.910 Alarm Need the full list of Yaskawa error codes
Unlike a hard "Fault," the A.910 is classified as a Warning. This means the motor will generally continue to run, but the drive’s digital operator will flash the code to indicate that the operation has exceeded the overload protection characteristics. Primary Causes and Remedies Potential Cause Recommended Remedy Mechanical Obstruction
Check the machine for jams, excessive friction, or worn bearings that increase the physical load on the motor. Wiring Issues
Verify that the servomotor and encoder cables are correctly wired and that there are no faulty contacts or loose connections. Operational Overload
Reduce the operation speed, lower the cycle frequency, or decrease the overall load applied to the motor. High Ambient Temp
Ensure the SERVOPACK panel temperature is below 55°C. Check cooling fans and ventilation filters for clogs. Parameter Settings
Check parameter Pn52B (Overload Warning Level). If it is set too low for your application, it may trigger the warning prematurely. Troubleshooting Steps
Monitor Current Consumption: Use the drive's monitor mode (e.g., Un002 for torque reference) to see if the motor is consistently drawing current near its rated limit.
Clear the Warning: If the cause is temporary, you can often clear the warning by cycling the power or using a "Warning Reset" command via the digital operator or SigmaWin+ software.
Check Hardware Integrity: If the warning persists even with no load, the internal current detection circuit of the SERVOPACK may be faulty, requiring a replacement of the drive unit.
For robotic applications specifically using the FS100 controller, a similar code (0910) may indicate a CPU Error, typically requiring a controller restart or hardware inspection.
If after performing Steps 1-5 you still see error code A910, you likely have a physical component failure. The repair requires:
In many cases, the cost of repair (especially for drives under 7.5kW) approaches the cost of a new drive. Yaskawa’s flat-rate repair service or an authorized repair center (e.g., Drives Warehouse, Radwell, or Yaskawa direct) is the recommended route for hardware failure.
Do not confuse A910 with these similar codes:
| Error Code | Name | Key Difference | | :--- | :--- | :--- | | A900 | Main Circuit Overvoltage | DC bus voltage too high (often decel issues) | | A915 | Control Power Undervoltage | Internal 24V/12V logic supply failure | | A910 | Main Circuit Undervoltage | DC bus too low | | UV1 (fault) | Main Circuit Undervoltage (V1000) | Same as A910 but shown as fault, not alarm | | UV3 (fault) | Soft-Charge Circuit Fault | Specific failure of the inrush relay |
If you see A910 repeatedly during deceleration, you actually might have an overvoltage (A900) problem that is causing the DC bus to oscillate and undershoot.