NC Servo Feeder Alarm Diagnosis
AL.50 is not a universal alarm definition across every servo brand. On Mitsubishi MELSERVO-JE MR-JE-_A, MR-JE-_B and MR-JE-_C amplifiers, AL.50 is Overload 1. Record the full drive model, the complete alarm display and the operating stage before checking the feeder.
What Does AL.50 Mean on a Mitsubishi MR-JE Servo Drive?
Mitsubishi Electric identifies alarm 50 as Overload 1 for the MR-JE-_A, MR-JE-_B and MR-JE-_C families. The alarm is generated when the load exceeds the amplifier’s overload-protection characteristic. The complete detail matters: the manual separates thermal-overload details during operation from details while stopped.
| Display or evidence | What it tells you | Next action |
|---|---|---|
| AL.50 on a confirmed MR-JE drive | Overload 1; the protection threshold was exceeded | Record the detail and occurrence stage before resetting |
| 50.1–50.3 | Thermal-overload detail during operation | Investigate load, wiring, brake release, encoder and stability using the exact manual |
| 50.4–50.6 | Thermal-overload detail during a stop | Check collision, servo-lock hunting, brake, wiring and the other listed drive-side causes |
| AL.50 on another brand or unknown drive | The meaning has not been established | Find the nameplate and use that manufacturer’s alarm manual |
Use the current manual for the installed hardware. The official Mitsubishi MR-JE troubleshooting manual is the source used for the MR-JE statements on this page.
AL.50 Is an Alarm Code, Not a “50% Alarm”
Searches such as “alarm 50%” can be misleading. In this context, 50 is the alarm number; it is not a statement that the motor is operating at 50% load. If load-ratio or overload-margin data are available in the drive software, record those values separately and interpret them with the manual for the exact amplifier.
Record These Facts Before Any Reset
- Hardware identity: feeder model, servo amplifier brand and full model, motor model and controller version.
- Complete display: AL.50 plus any decimal detail, controller message, time and alarm history.
- Occurrence stage: power-up, no-load jog, feed acceleration, constant feed, release, press dwell, servo-lock or stopping.
- Recent change: die, pilot pin, strip thickness, width, feed pitch, speed, guide, mounting, wiring, parameter or maintenance work.
- Material state: loaded or unloaded, clamped or released, strip tension, visible buckle, jam, burr or guide contact.
- Repeatability: whether it occurs at the same press angle, feed position, speed, die or material condition.
AL.50 Diagnostic Workflow
| Step | Question | Decision |
|---|---|---|
| 1. Confirm | Is this a Mitsubishi MR-JE drive, and what is the complete alarm detail? | If unknown, stop and obtain the correct manual. |
| 2. Classify | Did the alarm occur only with material, only in automatic mode, during release, during no-load jog or while stopped? | Choose the matching branch below. |
| 3. Isolate | Can the material path and feeder mechanism be inspected under an approved de-energized condition? | Remove obvious external resistance before drive-side work. |
| 4. Measure | What do load ratio, overload margin, wiring checks, brake state and alarm history show? | Use evidence instead of replacing components by guesswork. |
| 5. Correct | Was the actual cause removed under the released procedure? | Record the change and prepare a controlled retest. |
| 6. Verify | Does the feeder complete manual, single-feed and low-speed automatic tests without recurrence? | Release only after the acceptance result is recorded. |
If AL.50 Appears After a Die Change
A die change is one useful branch, not a universal diagnosis. Compare the new setup with the last known good job. Check the released pass line, die entrance, pilot-pin engagement, feed pitch, release command and the actual moment the feed rolls release the strip.
- Keep the press out of automatic operation and use only the approved setup mode.
- Confirm that the feeder releases before pilot correction requires the strip to move.
- Check whether the strip is still clamped while a pilot pin, stop or die feature is trying to reposition it.
- Compare the new die and job data with the previous setup; do not reuse a timing value merely because it worked on another die.
- Set feed-line height from the released installation and die data. There is no universal “3 mm lower” rule.
Feed-Line HeightA dedicated long-tail guide for feeder and die alignment.
Interface AcceptanceDocument-led verification of the feeder–press sequence.
If AL.50 Appears Only With Material Loaded
Look for resistance that is absent during no-load motion. A loaded-strip alarm can come from a pinched guide, a blocked entry, excessive upstream tension, incorrect roll pressure, strip buckling, burr contact, a die or pilot conflict, or material outside the released feeder range.
- Upstream: confirm the coil can unwind and the loop or straightener is not pulling against the feeder.
- At the rolls: inspect the strip path, roll opening, pressure setting, guide width and surface contamination.
- Downstream: inspect the die entrance, pilots, stops, guards and any point where the strip can be trapped.
If AL.50 Appears During No-Load Jog
An alarm without material narrows the search but does not prove a specific failed component. Under approved isolation, inspect the feeder for binding rolls, damaged bearings, gear interference, foreign material, a collision or another moving part that does not turn freely. On the drive side, follow the exact MR-JE detail table for motor power cable, U/V/W connection, brake release, encoder cable, effective load ratio, resonance and hardware condition.
Electrical and Servo-Drive Checks
Electrical checks belong to qualified personnel. The Mitsubishi MR-JE manual lists several possible causes; the installed machine may use only part of that hardware. Work from the wiring diagram and model-specific manual.
Power and motor wiring
Check the motor power cable and the released U/V/W connections. Record loose, damaged or incorrect connections before repair.
Brake state
If the selected motor has an electromagnetic brake, verify that it is released when motion is commanded.
Encoder path
Check the encoder cable destination, connection and damage. Do not condemn the encoder from the alarm number alone.
Load and stability
Review effective load ratio, overload margin and signs of resonance or hunting. Gain changes require the correct commissioning procedure.
Is AL.50 a Servo Motor Failure Alarm?
Not by itself. AL.50 confirms that overload protection operated on a supported MR-JE drive; it does not prove the motor, servo amplifier, encoder or electronic board has failed. Mechanical resistance, an unreleased brake, wiring, excessive load and instability are also listed diagnostic branches. Replace a motor or drive only after the prescribed checks isolate that component.
The same caution applies when an operator calls AL.50 a servo drive alarm or servo motor alarm. Those descriptions identify where the alarm is displayed, not which component failed. Preserve the code and operating conditions, then separate mechanical load, brake, wiring, encoder and drive evidence before replacing parts.
Reset, Cooling and Controlled Restart
Mitsubishi warns against repeatedly resetting overload alarms. Remove the cause, keep the system safe and allow the specified cooling period before resuming operation. The current MR-JE troubleshooting manual calls for at least 30 minutes of cooling for AL.50 before restart.
- Record the alarm and correct the proven cause.
- Confirm that guards, wiring, mechanical parts and the material path are restored.
- Confirm that the run command cannot cause an unexpected start during reset.
- Follow the amplifier and machine reset method; do not improvise a bypass.
- Test without material where the procedure permits, then single-feed with the approved material.
- Run low-speed automatic cycles and monitor recurrence, load evidence and the feeder–press sequence.
AL.50 Service Evidence to Send HENLI
| Evidence | Minimum detail | Why it matters |
|---|---|---|
| Nameplates | Feeder, amplifier and motor model photos | Prevents diagnosis against the wrong alarm manual |
| Alarm record | Full display, detail, history and time | Separates operating and stopped conditions |
| Occurrence video | Press angle, feeder rolls, strip and die entrance | Shows whether load coincides with release or pilot engagement |
| Job data | Material, width, thickness, pitch, speed and die | Identifies a change from the last known good setup |
| Checks completed | Isolation, mechanical findings, wiring, load ratio and retest | Avoids repeating unsafe or inconclusive work |
Frequently Asked Questions
Are AL50, AL.50, AL-50 and AL-050 the same?
They are common search spellings for a similar-looking alarm number, but the correct display and meaning must be confirmed from the installed drive. On supported Mitsubishi MR-JE models, the manual writes the alarm as AL. 50 and names it Overload 1.
Does AL.50 mean the servo motor is damaged?
No. It shows that overload protection operated on a supported MR-JE system. Mechanical load, brake state, wiring, encoder, resonance, amplifier and motor are separate diagnostic branches.
Can I reset AL.50 and continue production?
Do not repeatedly reset it. Record the evidence, remove the cause, follow the required cooling time and complete a controlled restart under the applicable machine and drive procedures.
Why can AL.50 appear after changing a die?
A new die can change pass line, pilot engagement or release timing. If the feeder still clamps the strip while the die is trying to reposition it, the resulting resistance can contribute to overload. Confirm this with the actual sequence instead of assuming it.
Where can I find Mitsubishi MR-JE-70A error codes?
Use the current Mitsubishi Electric MR-JE troubleshooting manual for the installed amplifier family. Confirm the complete model suffix because reset methods and supported functions can differ.
Related NC Servo Feeder Resources
Servo Feeder GuideSelection, specification and application boundaries.
NC Servo Feeder ModelsReview the HENLI product range and released configuration.
Send the Complete Alarm Evidence Before Replacing Parts
Share the feeder, amplifier and motor nameplates, full AL.50 display, job data, occurrence video and completed checks. HENLI can then compare the evidence with the supplied machine documentation.
